REVIEW
RENAL
ARTERY
ARTICLE
ANEURYSM
Polyaneurysmal Lesion of Kidney JULES
CHARRON,
RAYMOND
M.D.
BÉLANGER,
RENÉ VAUCLAIR,
M.D.
CLAUDE
M.D.
LEGER,
M.D.
ARAM RAZAVI, M.D. From the Departments of Urology, Radiology, and Pathology, Notre-Dame Hospital, Montreal, Quebec, Canada
_ ._ _
..__ __.
ABSTRACT - A case of innumerable renal artey aneurysms of probable congenital orrq tt i : I- ,ported. NO other lesion could be found in any other abdominal organ studied. We think it IIUI~ e as no similar case could be found in the medical làterature. Except fm right flank malaise, th(? Ijut ent was otherwise asymptomatic. The radiologie diagnostic methods are discussed, stressing tilP (lij ‘ewntial diagnosis of calci&ations in the area of the kidney. The management of renal aneurysnly i,>c ixussed in regard to the nephrectomy. - __. _.. - _._--.
Renal artery aneurysms are being discovered with increasing frequency but remain an uncommon pathologie entity. Since the first published case by Rouppe in 1770, as cited by Kyle,l many authors have periodically tabulated the cases reported in the medical literature.‘-’ In 1966 Kylel collected 304 cases, Glass and Uson4 added 20 more, and Tcherdakoff and Milliez5 28. It would now appear to have become a frequent occurrence to those who investigate arterial hypertension, according to Rousseau et al. * The radiologie refinements of angiography have given US a more realistic incidence and a better understanding of its implications.6 The incidence of renal artery aneurysms, based on autopsy studies, shows an average incidence of 0.01 per cent (Kment, 5 aneurysms in 41,437 autopsies; Howard et al., 1 case in 13,525 autopsies; and Sperling, 2 cases in 33,810 autopsies’). Similar figures were reported by Von Ronneng and Abeshouse.2 A report by Smith and Hinman,rO based on admissions at a University Hospital, shows an incidence of 1 in 8,000. However, the radiologie incidence is much higher, with Edsman” reporting a 0.73 per cent
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occurrence on renal arteriographies ;:III Z Tcherdakoffet a1.6 1.32 per cent. Acconlin: o Rousseau et al. 8 this differente of occurxen~ e is because many aneurysms, visible on artg ography can be overlooked on simple a latomic examination. The rate of frequency, site of occurre ice, and nature of the aneurysms can be smn tnlrized as follows: renal artery aneurysm represer ts 1 per cent of al1 aneurysms,’ age incidence ranges from one monthl’ to eighty-two years;r3,14 50 per cent of the cases have been discovered in the fifth decade;l 17 per cent are intrarenaltO 20 per cent bilatera14 and 30 per cent multiple;4*“,‘3 :he main trunk or first biiùrcation of a primaiy 1 ranch of the renal artery is the site of occurrence in 50 per cent of the cases;15 only 25 per ce:it of the aneurysms are calcified; and, accoiding to Vaughn, intrarenal aneurysms calcify less frequently than others. 5 Aneurysms are of two types: false arleurysms which are not limited by a normal cornI,onent of the arterial wall, and true aneurysms which are walled by diseased arterial tissue. The fermer are usually of traumatic origin, and the lnter are
1
congenital or acquired. Poutasse3 contends the lesions are caused by arteriosclerosis or fibromuscular disease of the artery. Good size saccular aneurysms of renal artery may be found in association with fibroplasia of the media. 16-‘* However, other conditions such as infection and periarteritis nodosa may also be responsible.lg The congenital lesions are said to occur because of a defective media of the arterial wall.’ Halpern and Currarino2’ reviewed 3 cases associated with the vascular lesions of neurofibromatosis. The clinical signs of renal aneurysms are few, nonspecific, and vary according to the size and type of the lesion. True aneurysm of smal1 size can be completely silent, whereas false aneurysm or large true aneurysm give rise to a dull flank pain. Abeshouse2 states that the pain may be colicky in nature followed with gastrointestinal derangements. Hematuria, microscopic or gross, is a frequent occurrence and reflects some kind of vascular injury with parenchymal infarction. Auscultation of the abdomen may reveal a bruit in 10 per cent of cases according to Ky1e.l This may represent a more pathognomonic sign.14 The association of arterial hypertension with renal aneurysm causes a certain degree of controversy. Glass and Uson4 make it “the most frequent physical finding observed” in 20 cases (75 per cent). Kylel reports it present in no more than 15 per cent of cases studied. Speculation as to the role of the aneurysm itself as the cause of the hypertension suggests two etiologic types. One type is the result of associated renal disease (arteriosclerosis, nephritis, periarteriosa nodosa). In another group of younger patients, the arterial hypertension appears to be in direct relation to the aneurysm, with complete cure by early nephrectomy. Our case has some unusual characteristics. The aneurysms are innumerable, both on the renal pedicle and on the finer arterial divisions. The other kidney is entirely normal, free of any vascular defect, as wel1 as the abdominal organs studied. This young patient did not have arterial hypertension. These lesions are thought to be of congenital origin. Case Report A twenty-four-year-old white woman was admitted to the hospital because of a painful mass in the right loin. The history dated back to one year when the patient began complaining of occasional lancinating low intensity pain in the right dorsolumbar area. Changes in position did
2
not affect the character of the pain; however, it appeared to increase when the patient was tired. She consulted her family physician who discovered a right flank mass, which was painless on palpation and freely movable. The patient was referred to US for further investigation and treatment. Her only other complaint was episodes of unexplained fever and progressive asthenia. Past history was unremarkable. Physical examination revealed a well-developed young lady of medium stature and apparent good health. Head and neck examinations were normal (including fundi). Cardiopulmonary examination revealed an apical grade I systolic murmur disappearing in the left lateral position. The arterial blood pressure taken repeatedly was in the vicinity of 100/70 mm. Hg. The abdomen appeared to be normal, but palpation revealed a 15-cm. mass in the right hypochondrium, slightly irregularmobile, and painless, extending to the midline anteriorly. Auscultation of this area revealed a murmur occupying al1 the systolic as wel1 as the beginning of the diastolic contraction of the heart. The biochemical profile yielded normal values. Urinalyses were consistently normal, as wel1 as the phenolsulfonphthalein clearance and blood creatinine. The intravenous pyelogram was interesting. Plain film of the abdomen revealed two calcific shadows projecting in the hilar and neighboring structure of the right kidney (Fig. 1A). The largest shadow consisted of a round formation with calcified contours of 5 cm. in diameter and 1 mm. or less in thickness. It was interrupted at the top portion where irregular and amorphous calcifications were seen (Fig. 1B). It had the appearance of a broken egg shell. The second calcification was 1 cm. in diameter, situated higher up in the right kidney. It was nonhomogeneous and irregular at the periphery (Fig. 1A). The bipolar dimension of the right kidney was 14 cm. and the left organ 10 cm. NO osseous erosion of the adjacent lumbar vertebra was seen. After intravenous injection of radiopaque media, the hilar mass appeared to be opacified (Fig. 1C). It pushed the renal pelvis downward while the upper caliceal system was dilated and displaced upward (Fig. 1D). The probable vascular origin of these lesions was confirmed by abdominal angiography, using the Seldinger technique of cannulating the right common femoral artery for right renal selective arteriography and lefi common femoral artery to obtain aortography.
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FIGURE 1. (A)Abdomen: broken egg-shell calcijìcation in hilar region of right kidney (5 cm. in diameter) (arrows); smaller (1 cm. in diameter) irregular dense calcifìcation (arrow). (B) Close-up uiew: area of interruption of classic ring calcijìcation (arrows). (C) Intravenous pyelogram (one-minute film): aneurysm appears to be already dense from possible accumulation of contrast medium. (Dj Intravenous pyelogram: displacement and indentation of pelvic cavity of right kidney by aneurysm with obstructive dilatation of upper group of calyces.
FIGURE 2. (A and B) Aortography, arterial phase: integrity of other vascular structures including splenic artery showing easily recognizable kinking by alternated stereoscopic anteropostertor views. (Films at oneand-a-half seconds; stereoscopic view at two seconds after injection.)
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3
~‘hc~e show;cd innumerable aneurysms of the right renal artery and its tributaries including most of the kidney parenchyma. With aortograpIl?,, no other aneurysm could be seen in any other abdominal organ studied by alternated stereoscopic views (Fig. 2A and B). The selective right renal arteriography using 15 cc. diatrizoate meglumine and sodium (Renografin-76) provided details of the vascular pathologie condition. The right renal artery had a diameter of 1.1 cm. with a 5-cm. saccular aneurysm. The secondary divisions were the site of multiple aneurysms varying in size from a few millimeters to 2 cm. in diameter (Fig. 3A). The test injection for selective arteriography, recorded on videotape, revealed a marked and prolonged turbulente of the contrast medium in the largest of the aneurysms. Further injection recorded on cinefilm allowed US to review the dynamics.
Xumerous lesions were noted on the interlobar as wel1 as the arcuate arteries. Many interlobar arteries were slightly increased in diameter (Fig. 3B). The nephrogram of the upper part of thc right kidney was late and not as dense as the rest of the kidney, suggesting the upper arteriat branch as the site of origin of the largest lesion (Fig. 3C). There was no evidente of early venous return. At the end of the aortography, the right renal vein was opacified and measured 3 cm. in diameter (Fig. 3D). Because of the clinical symptoms and the extent of the disease, surgical treatment was since the patient was so planned. However, young, the procedure was to be conservative partial nephrectomy. Through a right paramedian incision, the right kidney and pedicle were explored. The extent of the parenchymal lesions became more evident. and precluded any attempt at a conservative procedure (Fig. 4A). No portion of the kidne!.
FIGURE 4. (A) Surgical specimen showing size of vessels; arrows point to some aneurysms. specimen; note large aneurysm compressing renal pelvis.
could be salvaged, and a simple nephrectomy was carried out. The size of the renal pedicle can be appreciated in Figure 4A. The renal vein was the size of a normal vena cava (Fig. 4B). The patient had a succes&1 recovery and was discharged from the hospita1 on the eighth postoperative day. She was seen one year later at follow-up and has remained completely asymptomatic. Comment Comments can be made on three aspects of renal artery aneurysms; namely, the radiologie studies necessary for diagnosis, the pathologie considerations of the cause, and the clinical management of such patients. Radiologie
remarks
The present case incites one to study the aneurysmal calcifications by defining it and establishing its variants in the differential diagnosis on
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(B) Removed
the plain film of the abdomen, and to observe the usual relations of the renal aneurysms with the renal sinus and the upper urinary tract cavities. The essential role of angiography should be stressed as wel1 as certain angiologic aspects of renal aneurysm. Other pathologie conditions have common traits with our present case and wil1 be established. By studying the calcifications on the aneurysmal wall, we find that as early as 1917, Key and Akerlundzl pointed out the occurrence of ringshaped calcification of typical appearance in renal arterial aneurysm on a plain film of the kidney. Later, various authors described more thoroughly these characteristic calcifications7*13,‘4.22 which apply mostly to true aneurysm since they are rarely present in false aneurysm.‘,6,7 However, occasionally false aneurysm wil1 manifest itself as a mottled, variegated, or punctate region of calcification.13 The frequency of the
5
calcification of the aneurysmal wal1 is mentioned by many authors and is extremely variable: 60 per cent, l3 50 per cent, 4,7 50 per cent of extraparenchymal aneurysm,13 33 to 50 per cent,12,23 over 25 per cent1 36 per cent, 24 27 per centZ 20 per cent5 and 10 per cent6 Calcifications of such lesions have been described in children eight years oldz6 and even six-and-one-half years old. 7 The calcification is the opaque image of the calcified aneurysmal sac. It is oval or circular in shape with a radiolucent center representing the lumen of the aneurysmal vessel. This may be completely opacified at arteriography depending on whether or not it contains a thrombus. The calcification is usually fine with well-defined contours. A calcified aneurysm which is partially thrombosed wil1 consequently be only partially opacified on arteriography. r’ A completely thrombosed aneurysm with calcified wal1 and radiolucent center on plain film may be confirmed only by angiography, in which case no contrast medium wil1 appear in the lumen.‘,27,28 Pictures may represent peripheral infarcts with scarring and retraction. 27 The classic aneurysmal calcification has many names. Perusal of the literature wil1 yield such terms as: ringlike, l2 shell-like, l2 or ring-shapedcalcification, 11a21 calcified ring appearance, 6 classic ring calcification fine wreath or ringlike, vascular type of calcification,14 semicircular, r1 “signet ring,” or “broken-wreath” calcification, 1 calcific shadow incompletely circular, egg shell in configuration, r3 “image en coquille d’oeuf brisé”2g “aspect en anneau brisé,“* “image en anneau brisé,“6 calcification en anneau brisé5 (broken ring), characteristic signet-ring or halo-shaped calcification,“‘and calcified, broken, wreathlike density.31 The signet-ring or broken-wreath calcification is, according to Kyle, ’ diagnostic of atherosclerotic extrarenal artery aneurysm. These calcifications have important characteristics. Usually, there is an interrupted area representing the point of origin of the artery. 5,7~14,26,2gOne must remember that the calcification may only be partial, in which case it is said to be an opaque fingernail print marking.7 The absente of interruption in a calcified ring raises other possible diagnoses. Progression in size of circular calcification between two consecutive radiographies may suggest aneurysm. Berneike and Pollock3’ have observed such a case over a two-year period. Differential diagnosis must be made with the following possibilities: renal calculus, 7~13ureteral
mesenteric nodes,4~7*1’4,14~‘H calculus, l3 calcified biliary stones, 7~19~14,2gadrenal cysts,33,3” pheochromocytoma (calcification in a fibrotic wal1 of’:1 cystic area within the tumor35 and calcification in a fibrotic wal1 of a tumor nodule35), calcified arteriosclerotic plaques in a tortuous renal 01’ splenic artery, 7 hematomas, 7*13*14,27,36perirenal of lumbar verteabscesses, l3 osteochondroma bra ‘,r3~14 intraperitoneal hydatid cysts, 7 renal hydatid cysts often accompanied by smaller ringlike calcified daughter cysts, 13,27congenital multicystic kidney, 37 and renal hamartoma. 3* One must also consider the possibihty of calcified aneurysm of other neighboring arteries such as the splenic, hepatic, pancreatic, or mesenteric arteries. 7 However, the most likely differential diagnosis is made with: benign simple renal cysts,“g renal cel1 carcinoma (calcified fibrous pseudocapsule surrounding several renal cel1 carcinoinas) 12*3g,40tuberculeus or nonspecific calcified lipogranuloma with abscesses, 7~14,3gsclerosiug fibrotic calcified pseudocapsule, renal cortical adenoma, renal cortical adenoma with hemorrhage and necrosis,41 cystic renal adenoma with degenerative changes and intramural calcificution, and congenital or acquired arteriovenous fistula. 7,27,42 Simple renal cysts or renal cel1 carcinotna should be forernost in our differential diagnosis because of their more common occurrencc. Daniel et al. 3g in a review of 2,709 cases of renal masses found that 1 to 2 per cent of simple cvsts and 10 per cent of renal cel1 carcinomas contained roentgenographically visible calcium. While peripheral egg-shell calcifications withoutcalciurn in the mass was usually associated with benign simple cysts, the risk of malignant disease was stil1 about 20 per cent. The site of annular calcium in the renal area is very important; hilar deposits suggest aneurysm whereas peripheral sites occur more frequently with tumoral lesions. Rarely aneurysmal calcific shadow wil1 project over the renal substance. 13*43 The incidence of calcification in renal artery aneurysm appeared to decrease in relation to the proximity of the aneurysm to the 80 per cent kidney substance. 4 Approximately of the renal artery aneurysms are extrarenal. ‘O While calcification in renal aneurysm is common. intrarenal aneurysms calcify less frequently than extrarenal aneurysms. *3 Intravenous pyelogram is essential to localize calcifications adequately. The collecting system is frequently compressed, displaced with image of indentation.12,44*45 If the compression is at the
classic signs of usual renal artery aneurysms. Aneurysms of peripheral arteries are rare and are present in periarteritis nodosa, angiitis of drug abuse, and rarely in malignant hypertension with necrotizing arteritis. 47 In this latter disease there are luminal irregularities and “pruning of the vascular bed” and disparity in the size of the centra1 and peripheral vessels.48 The vascular pattern of periarteritis nodosa and angiitis of drug abuse are indistinguishable roentgenographically, and in most instances the aneurysms when present range from 1 to 5 mm. in diameter. 47Despite the peripheral microaneurysms in our case, the size and situation of the aneurysms militate against the possibilities of angiitis of drug abuse or periarteritis nodosa. However, smal1 saccular aneurysm may be found at the bifurcation of the renal artery in the latter disease.12 In these cases of angiitis, the aneurysms are usually scattered and involve the interlobar, arcuate, and even interlobular arteries. 19*47~49-51 Moreover, other radiologie signs may be observed, and scattered areas ofnecrotizing arteritis may be present. The contour of the interlobar arteries may be irregular and a diminution in number may be apparent. The renal cortex is and Main aneuysm (1); satellite aneuysw irregular. 47 Scarring from thromboses FIGURE 6. (2 and 3). infarctions may be observed.19 Leary and Utz13 illustrated the angiographic pattern of a case with multiple intrarenal aneurysms, probably lobar and hilar veins. Microscopic examination congenital, in a boy thirteen years of age. of the walls of the aneurysms showed anticipated In our case, in spite of the radiologie identichanges: calcification and fibrosis of the wal1 fication of peripheral microaneurysms and a leading to a dissociation of the elastic and muscucertain degree of dilatation of the interlobar lar structures and atheromatous deposits at the arteries, we believe the patient had a congenital leve1 of the intima. polyaneurysmal dysplasia of the arterial bed of The congenital nature of the aneurysms was the right kidney. demonstrated by many findings: (1) At the leve1 of the aneurysmal dilatations, the atheromatous deposits were sharply limited to the dilated porPathologie jìndings tion of the artery. The elastic and muscular strucThe kidney weighed 200 Gm. The renal artery tures of the wal1 were interrupted as wel1 and was cannulated and injected under pressure with modified in an abrupt fashion at a junction spot a normal saline solution. An aneurysmal, saccular easily localized between the normal arterial wal1 dilatation 5 cm. in diameter was demonstrated on and that of the aneurysm, this contrary to prothe primary renal artery (Fig. 6). Satellite aneugressive changes of the arterial wal1 in proximity rysms corresponding to the previous radiologie of the aneurysm of atheromatous nature. description were observed at the hilar branches (2) The microscopic study demonstrated of the renal artery. These aneurysms were lined many unsuspected lesions of the arteries on gross with atheromatous deposits, while their walls examination and situated in the hilus area. These showed calcified plaques. were zones of muscular thinning and abrupt interruption of the elastic membranes, especially the Serial sections did not otherwise demonstrate internal one, accompanied secondarily by fibrosis evidente of anomalies of the venous wal1 or the and atheromatosis of the intima (Fig. 7A). In excretory ducts, although the proximal portion of brief these lesions represented aneurysms in the the ureter was slightly dilated. Also a significant state of formation. degree of dilatation was observed in the inter-
8
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/ JANUARY 1975 / VOLUME V, NUMBER 1
Aneurysm size varies from 1 to 2 cm. but rnay reach 10 to 12 cm. in diameter.’ Segmental ischemia of the kidney may also occur.‘I In some instances the local circulation peripheral to an aneurysm may be markedly reduced and the peripheral vasculature sparse. 23
FIGURE 5. Kidney specimen injected with radiopaque media shoting multiple aneurysms, microaneurysm of interlobular artery (arrow), and dilated interlobar artery (double arrowi.
pyeloureteral junction, hydronephrosis may ensue.7,16 Morin et a1.46 reported a case of unilateral cortical necrosis with the contralateral kidney bearing a calcified renal artery aneurysm with partial obstruction of the ureter. Often the kidney with the aneurysm may be smaller and even atrophic, but it may also be slightly larger than the contralateral organ.’ Angiography even though it affects a selected group of patients yields a frequency of 0.73 per cent,” 1.07 per cent,’ and 1.32 per cent6 of demonstrable renal artery aneurysms. Selective arteriography is the procedure of choice to diagnose and localize an aneurysm. Visibly calcified aneurysms on plain roentgenograms are no real indication of the total number of aneurysms in any given patientZ4 Other ipsilateral noncalcified aneurysms may be discovered. The aneurysms are usually saccular, and 60 to 70 per cent are located in the main renal artery or its bifurcation, or in a primary branch. l3 Aneurysms involving the smaller arterial branches, that is intrarenal, are uncommon.r4 Only 17 per cent of al1 reported cases of renal aneurysms were intrarenal.‘O Kyle in 1968l reported 20 such cases excluding microaneurysms of periarteriosa nodosa.
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Aneurysm may cause an incomplete and sometimes delayed filling of distal vessels as wel1 as prolonged retention of contrast material.“” Aortography cannot be omitted despite knowledge gained by selective renal arteriography because nearly half the cases of aneurysms are present bilaterally and sometimes in other organs as well. l2 They have been reported in the splenie. hepatic, gastroduodenal, superior mesenteric. and renal arteries” and sometimes multiply in some of these arteries.’ One case was reported in a one-month-old baby. l2 Congenital intrarenal aneurysms are usually saccular or fusiform, with or without calcification. Of the 50 reported cases of true intraparenchymal renal artery aneurysms, one-third were considered congenital in origin, one-third resulted from atherosclerosis, and one-third were associated with polyarteritis.‘” We believe that our case is radiologically compatible with a eongenital polyaneurysmal dysplasia of the kidney affecting only one organ of the abdomen. One has the classic shell-like calcification. Another has a calcified thrombosis in a secondary division of the renal artery, hut without the radiolucent center; the selective renal arteriography could not confirm the presence of circulating opaque material in the center of the calcified formation It could represent a calcified completely thrombosed aneurysm. The exaggerated size of the diseased kidney can be explained by the increased blood capacity of these aneurysms. There is an ischemic area in the upper pole resulting from important turbulente in the mam aneurysm thus delaying the filling of distal branches. The turbulente was recorded on cinefilm. It is probable that al1 the other aneurysms in the kidney are part of the same pathologie aneurysmal process. None of the arteries showed radiologie changes compatible with angiitis. By injecting the removed specimen with contrast material, it was possible to demonstrate the numerous aneurysms including peripheral microaneurysms (Fig. 5). Multiple smal1 kidney aneurysms usually occur in periarteritis nodosa or necrotizing angiitis associated with drug abuse. The differential diagnosis with these conditions was established by
FIGURE 7. (A) Wal1 of main aneuysm (1); hilar branches of renal artey (2); thinned out zone of arterial wal1 with interruption of internal and external elastic membranes (3); and jibrosis of intima (4) (Weigert x60). (B) lnterlobar artey: (1) parietal thinning with interruption of internal elastic membrane (Weigert x60).
(3) Certain interlobar arteries had otherwise presented parietal modifications not accompanied with fibrous reactions or atheromatous changes of the intima. These modifications were characterized by zones of muscular thinning or interrupted intemal elastic membranes, or both these phenomena (Fig. 7B). The latter lesions probably represented the pathologie basis of future aneurysmal dilatation. Management
The obvious decision is one of surgical intervention or of passive observation, considering the clinical complaints and the possible complications. The role of a renal aneurysm in arterial hypertension is difficult to assess. Some clinics specializing in arterial hypertension find a high inci(1.32 per cent), but dence of renal aneurysms they may represent a complication of the initial vascular disease, the arteriosclerosis with arterial hypertension causing the formation of aneurysms.6 However, as stated, thrombosis of an aneurysm can cause renal ischemia with resulting hypertension. However, the most important reason for surgical treatment is the danger of spontaneous rupture. The type and nature of the aneurysm, however, influences the frequency of rupture. McKiel, Graf, and Callahan in 196615 collected 32 cases of aneurysmal ruptures in the literature, 27 resulting in death. Al1 were cases of noncalcified lesion. Pregnancy is also a favoring condition to rupture. l Viville and others state that 90 per cent of the ruptures occurred in hyper-
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tensive patients. 5 Young patients, according to Gérard, are more likely to progress to eventual rupture;5 the same is true of symptomatic aneurysms. False intrarenal aneurysms are especially susceptible to spontaneous rupture. l” Ippolito and Le Veenz found that 25 per cent of al1 noncalcified aneurysms wil1 rupture, with a mortahty rate of 85 per cent. It becomes obvious that most aneurysms require surgical treatment, exceptions being smal1 (less than 1.5 cm.), solitary, calcified, asymptomatic, or extraparenchymal lesions in the normotensive middle-aged or older patient.3,‘5 Patel, Cormier, and Arthur53 go further by considering the possibility of conservative surgical intervention, making it clear that if the aneurysm, only, can be removed, it should be. The type of surgical procedure has evolved toward more conservative techniques. Atkinson54 considered nephrectomy as the choice procedure with a 6 per cent mortality rate as compared with 53 per cent in conservative procedures. However, as reconstructive procedures become more sophisticated, the mortality becomes more acceptable. Partial nephrectomy is preferred to total nephrectomy whenever feasible. Excision of saccular aneurysms with an arterial wal1 repair is the procedure’of choice if the lesion is on the pedicle. Fusiform aneurysms on the main trunk can be resected with an end to end reanastomosis. Other complications warrant surgical intervention and may include pain, persistent hematuria, infarction, and erosion of surrounding structures.
9
1656 Est. Montreal
133,
Sherbrooke
Quebec, (DR.
Canada
CHARRON)
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Med.
report of 2 cases and review of the literature, Urol. Cutan. Rev. 55: 451 (1951). POUTASSE, E. F.: Renal artery aneurysms: their natura1 history and surgery, J. Urol. 95: 297 (1966). GLASS, P. M., and USON, A. C.: Aneurysms of the renal artery: a study of 20 cases, ibid. 98: 285 (1967). TCHERDAKOFF, P., and MILLIEZ, P.: Anévrismes de l’artère rénale: rapport préliminaire à propos de 28 cas, Ann. Cardiol. Angeiol. (Paris) 17: 111 (1968). TCHERDAKOFF, P., et nl. : Anévrisme de I’artère rénale chez les malades hypertendus, 42 cas, Presse Med.
7.
Can.
21.
causing hypertension in neurofìbromatosis, N. Eng]. J. Med. 273: 248 (1965). (:.‘! KEY, E., and AKERLUND, A., cited hy Edsman.
-33.
Radiology
Clin. Radiol.
24: 468 (1973).
80: 786 (1963).
34.
PALITRJNSKAS. A. J.. CHKISTESSEX, \V. H., ~I.AHRISON, J. H.. and SOSMAN. M. C.: Calcified adrenal cysts. Am. J. Roentgenol. Radium Ther. Nuc]. hled 82: 853 (1959). 35. GRAINGER, R. Cc., L~oun, C. A., and WILI,IAMS, J. J.: Egg-shell calcification: a sign of pheochromocytorna, Clin. Radio]. 18: 282 i1967). 36. THOMPSON, C. J.. and CI_XP, 0. S.: Perplexingqstrc masses 37.
38.
39.
40.
41.
42.
43.
near the kidney.
J. Urol.
89: 370 !lQ63).
KYAW. Ll. bf.: The radiological diagnosis ofcongenital multicystic kidney. “Radiological triad.” Clin. Radiol. 25: 45 (1974). ETTIN(;ER, A., and EI~KIN, 41.: Value of plain film in renal mass lesions (tumours and cysts). Radioloq. 62: 372 (1954). DANIEL.. mT. W.~ JR.. c’t (11.: Calcified renal mass~s A review of ten years experience at the Mayo Clinic. ibid. 103: 503 (1972). KIKKAWA, K.. and LASER. E. C.: “Ring-like” o, “rim-like” calcification in renal cel1 carcinoma, Am. J. Roentgenol. Radium Ther. Xucl. Med. 107: 734 (1969). C4NYON, A. II., ZANON, B., JR., and KARKAS, B. CG.. Cystic calcification in the kidney. Its occurrencp in malignant renal tumors, ibid. 84: 837 (1960). LACKNER, H., WALKER, W. C., and TILLACK, T. ‘12’. Calcified intrarenal arteriovenous fistula with spontaneous rupture: a case report, J. Urol. 97: 997 (19671. V~ITGHAN, T. J.. BARRY. W. F., JR., JEFFORDS, D. I,.. and JOHNSRUDE. 1. S.: Kenal artery aneurysms and hypertension, Radiology 99: 287 (1971).
44. LAMARQUE, J. L., et al. : Les pseudo-tumeurs rénales. Etiologies et aspects radiologiques, Ann. Radiol. 15: 841 (1972). 45. BROWN, R. FLOCKS, R. in the renal Nucl. Med.
C., JONES, M. C., JR., BOLDUS, R., and H.: Lesions causing radiolucent defects pelvis, Am. J. Roentgenol. Radium. Ther. 119: 770 (1973).
46. MORIN, Y., et al. : Nécrose corticde unilatérale avec sténose de l’uretère et anévrisme sacciforme de I’artère du côté du rein protégé. Une observation, Nouv. Presse Med. 2: 635 (1973). 47. HALPERN, M., and CITRON, B. P.: Necrotizing angiitis associated with drug abuse, Am. J. Roentgenol. Radium Ther. Nucl. Med. 111: 663 (1971). 48. HALPERN, M.: Angiography in chronic renal disease and renal failure. Malignant hypertension, Radiol. Clin. North Am. 10: 467 (1972).
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49. HERSCHMAN,A., BLUM, R., and LEE, Y. C.: Angiography findings in polyarteritis nodosa, Radiology 94: 147 (1970). 50. CAPPS, J. H., and KLEIN, R. M.: Polyarteritis nodosa as a cause of perirenal and retroperitoneal hemorrhage, ibid. 94: 143 (1970). 51. LEMIEUX, G., MIRANDA, J., DAGENAIS, Y. M., and FONTAINE, A. : Importante de l’angiographie rénale dans le diagnostic de la polyartérite noueuse, Union Med. Can. 102: 1064 (1973). 52. EDWARDS, J. E.: Acquired Diseases of the Heart and Great Vessels, Philadelphia, W. B. Saunders Co. 1961, vol. 3, p. 1264. 53. PATEL, J., CORMIER, J. M., and ARTHUR, E.: Remarques sur les anévrysmes de l’artére rénale, Presse Med. 74: 1021 (1966). 54. ATKINSON, R. L.: Aneurysm of the renal artery, J. Urol. 72: 117 (1954).
11
RENAL
ARTERY
ARTICLE
ANEURYSM
Polyaneurysmal Lesion of Kidney JULES
CHARRON,
RAYMOND
M.D.
BÉLANGER,
RENÉ VAUCLAIR,
M.D.
CLAUDE
M.D.
LEGER,
M.D.
ARAM RAZAVI, M.D. From the Departments of Urology, Radiology, and Pathology, Notre-Dame Hospital, Montreal, Quebec, Canada
_ ._ _
..__ __.
ABSTRACT - A case of innumerable renal artey aneurysms of probable congenital orrq tt i : I- ,ported. NO other lesion could be found in any other abdominal organ studied. We think it IIUI~ e as no similar case could be found in the medical làterature. Except fm right flank malaise, th(? Ijut ent was otherwise asymptomatic. The radiologie diagnostic methods are discussed, stressing tilP (lij ‘ewntial diagnosis of calci&ations in the area of the kidney. The management of renal aneurysnly i,>c ixussed in regard to the nephrectomy. - __. _.. - _._--.
Renal artery aneurysms are being discovered with increasing frequency but remain an uncommon pathologie entity. Since the first published case by Rouppe in 1770, as cited by Kyle,l many authors have periodically tabulated the cases reported in the medical literature.‘-’ In 1966 Kylel collected 304 cases, Glass and Uson4 added 20 more, and Tcherdakoff and Milliez5 28. It would now appear to have become a frequent occurrence to those who investigate arterial hypertension, according to Rousseau et al. * The radiologie refinements of angiography have given US a more realistic incidence and a better understanding of its implications.6 The incidence of renal artery aneurysms, based on autopsy studies, shows an average incidence of 0.01 per cent (Kment, 5 aneurysms in 41,437 autopsies; Howard et al., 1 case in 13,525 autopsies; and Sperling, 2 cases in 33,810 autopsies’). Similar figures were reported by Von Ronneng and Abeshouse.2 A report by Smith and Hinman,rO based on admissions at a University Hospital, shows an incidence of 1 in 8,000. However, the radiologie incidence is much higher, with Edsman” reporting a 0.73 per cent
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/ JANUARY 1975 / VOLUME V, NUMBER 1
occurrence on renal arteriographies ;:III Z Tcherdakoffet a1.6 1.32 per cent. Acconlin: o Rousseau et al. 8 this differente of occurxen~ e is because many aneurysms, visible on artg ography can be overlooked on simple a latomic examination. The rate of frequency, site of occurre ice, and nature of the aneurysms can be smn tnlrized as follows: renal artery aneurysm represer ts 1 per cent of al1 aneurysms,’ age incidence ranges from one monthl’ to eighty-two years;r3,14 50 per cent of the cases have been discovered in the fifth decade;l 17 per cent are intrarenaltO 20 per cent bilatera14 and 30 per cent multiple;4*“,‘3 :he main trunk or first biiùrcation of a primaiy 1 ranch of the renal artery is the site of occurrence in 50 per cent of the cases;15 only 25 per ce:it of the aneurysms are calcified; and, accoiding to Vaughn, intrarenal aneurysms calcify less frequently than others. 5 Aneurysms are of two types: false arleurysms which are not limited by a normal cornI,onent of the arterial wall, and true aneurysms which are walled by diseased arterial tissue. The fermer are usually of traumatic origin, and the lnter are
1
congenital or acquired. Poutasse3 contends the lesions are caused by arteriosclerosis or fibromuscular disease of the artery. Good size saccular aneurysms of renal artery may be found in association with fibroplasia of the media. 16-‘* However, other conditions such as infection and periarteritis nodosa may also be responsible.lg The congenital lesions are said to occur because of a defective media of the arterial wall.’ Halpern and Currarino2’ reviewed 3 cases associated with the vascular lesions of neurofibromatosis. The clinical signs of renal aneurysms are few, nonspecific, and vary according to the size and type of the lesion. True aneurysm of smal1 size can be completely silent, whereas false aneurysm or large true aneurysm give rise to a dull flank pain. Abeshouse2 states that the pain may be colicky in nature followed with gastrointestinal derangements. Hematuria, microscopic or gross, is a frequent occurrence and reflects some kind of vascular injury with parenchymal infarction. Auscultation of the abdomen may reveal a bruit in 10 per cent of cases according to Ky1e.l This may represent a more pathognomonic sign.14 The association of arterial hypertension with renal aneurysm causes a certain degree of controversy. Glass and Uson4 make it “the most frequent physical finding observed” in 20 cases (75 per cent). Kylel reports it present in no more than 15 per cent of cases studied. Speculation as to the role of the aneurysm itself as the cause of the hypertension suggests two etiologic types. One type is the result of associated renal disease (arteriosclerosis, nephritis, periarteriosa nodosa). In another group of younger patients, the arterial hypertension appears to be in direct relation to the aneurysm, with complete cure by early nephrectomy. Our case has some unusual characteristics. The aneurysms are innumerable, both on the renal pedicle and on the finer arterial divisions. The other kidney is entirely normal, free of any vascular defect, as wel1 as the abdominal organs studied. This young patient did not have arterial hypertension. These lesions are thought to be of congenital origin. Case Report A twenty-four-year-old white woman was admitted to the hospital because of a painful mass in the right loin. The history dated back to one year when the patient began complaining of occasional lancinating low intensity pain in the right dorsolumbar area. Changes in position did
2
not affect the character of the pain; however, it appeared to increase when the patient was tired. She consulted her family physician who discovered a right flank mass, which was painless on palpation and freely movable. The patient was referred to US for further investigation and treatment. Her only other complaint was episodes of unexplained fever and progressive asthenia. Past history was unremarkable. Physical examination revealed a well-developed young lady of medium stature and apparent good health. Head and neck examinations were normal (including fundi). Cardiopulmonary examination revealed an apical grade I systolic murmur disappearing in the left lateral position. The arterial blood pressure taken repeatedly was in the vicinity of 100/70 mm. Hg. The abdomen appeared to be normal, but palpation revealed a 15-cm. mass in the right hypochondrium, slightly irregularmobile, and painless, extending to the midline anteriorly. Auscultation of this area revealed a murmur occupying al1 the systolic as wel1 as the beginning of the diastolic contraction of the heart. The biochemical profile yielded normal values. Urinalyses were consistently normal, as wel1 as the phenolsulfonphthalein clearance and blood creatinine. The intravenous pyelogram was interesting. Plain film of the abdomen revealed two calcific shadows projecting in the hilar and neighboring structure of the right kidney (Fig. 1A). The largest shadow consisted of a round formation with calcified contours of 5 cm. in diameter and 1 mm. or less in thickness. It was interrupted at the top portion where irregular and amorphous calcifications were seen (Fig. 1B). It had the appearance of a broken egg shell. The second calcification was 1 cm. in diameter, situated higher up in the right kidney. It was nonhomogeneous and irregular at the periphery (Fig. 1A). The bipolar dimension of the right kidney was 14 cm. and the left organ 10 cm. NO osseous erosion of the adjacent lumbar vertebra was seen. After intravenous injection of radiopaque media, the hilar mass appeared to be opacified (Fig. 1C). It pushed the renal pelvis downward while the upper caliceal system was dilated and displaced upward (Fig. 1D). The probable vascular origin of these lesions was confirmed by abdominal angiography, using the Seldinger technique of cannulating the right common femoral artery for right renal selective arteriography and lefi common femoral artery to obtain aortography.
CHOLOC:k
!
JAKUARY 1975 / VOLUME V, NUMBEH 1
FIGURE 1. (A)Abdomen: broken egg-shell calcijìcation in hilar region of right kidney (5 cm. in diameter) (arrows); smaller (1 cm. in diameter) irregular dense calcifìcation (arrow). (B) Close-up uiew: area of interruption of classic ring calcijìcation (arrows). (C) Intravenous pyelogram (one-minute film): aneurysm appears to be already dense from possible accumulation of contrast medium. (Dj Intravenous pyelogram: displacement and indentation of pelvic cavity of right kidney by aneurysm with obstructive dilatation of upper group of calyces.
FIGURE 2. (A and B) Aortography, arterial phase: integrity of other vascular structures including splenic artery showing easily recognizable kinking by alternated stereoscopic anteropostertor views. (Films at oneand-a-half seconds; stereoscopic view at two seconds after injection.)
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/ JANUARY1975 / VOLUMEV,NUMBERl
3
~‘hc~e show;cd innumerable aneurysms of the right renal artery and its tributaries including most of the kidney parenchyma. With aortograpIl?,, no other aneurysm could be seen in any other abdominal organ studied by alternated stereoscopic views (Fig. 2A and B). The selective right renal arteriography using 15 cc. diatrizoate meglumine and sodium (Renografin-76) provided details of the vascular pathologie condition. The right renal artery had a diameter of 1.1 cm. with a 5-cm. saccular aneurysm. The secondary divisions were the site of multiple aneurysms varying in size from a few millimeters to 2 cm. in diameter (Fig. 3A). The test injection for selective arteriography, recorded on videotape, revealed a marked and prolonged turbulente of the contrast medium in the largest of the aneurysms. Further injection recorded on cinefilm allowed US to review the dynamics.
Xumerous lesions were noted on the interlobar as wel1 as the arcuate arteries. Many interlobar arteries were slightly increased in diameter (Fig. 3B). The nephrogram of the upper part of thc right kidney was late and not as dense as the rest of the kidney, suggesting the upper arteriat branch as the site of origin of the largest lesion (Fig. 3C). There was no evidente of early venous return. At the end of the aortography, the right renal vein was opacified and measured 3 cm. in diameter (Fig. 3D). Because of the clinical symptoms and the extent of the disease, surgical treatment was since the patient was so planned. However, young, the procedure was to be conservative partial nephrectomy. Through a right paramedian incision, the right kidney and pedicle were explored. The extent of the parenchymal lesions became more evident. and precluded any attempt at a conservative procedure (Fig. 4A). No portion of the kidne!.
FIGURE 4. (A) Surgical specimen showing size of vessels; arrows point to some aneurysms. specimen; note large aneurysm compressing renal pelvis.
could be salvaged, and a simple nephrectomy was carried out. The size of the renal pedicle can be appreciated in Figure 4A. The renal vein was the size of a normal vena cava (Fig. 4B). The patient had a succes&1 recovery and was discharged from the hospita1 on the eighth postoperative day. She was seen one year later at follow-up and has remained completely asymptomatic. Comment Comments can be made on three aspects of renal artery aneurysms; namely, the radiologie studies necessary for diagnosis, the pathologie considerations of the cause, and the clinical management of such patients. Radiologie
remarks
The present case incites one to study the aneurysmal calcifications by defining it and establishing its variants in the differential diagnosis on
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/ JANUARY 1975 / VOLUME V, NUMBER 1
(B) Removed
the plain film of the abdomen, and to observe the usual relations of the renal aneurysms with the renal sinus and the upper urinary tract cavities. The essential role of angiography should be stressed as wel1 as certain angiologic aspects of renal aneurysm. Other pathologie conditions have common traits with our present case and wil1 be established. By studying the calcifications on the aneurysmal wall, we find that as early as 1917, Key and Akerlundzl pointed out the occurrence of ringshaped calcification of typical appearance in renal arterial aneurysm on a plain film of the kidney. Later, various authors described more thoroughly these characteristic calcifications7*13,‘4.22 which apply mostly to true aneurysm since they are rarely present in false aneurysm.‘,6,7 However, occasionally false aneurysm wil1 manifest itself as a mottled, variegated, or punctate region of calcification.13 The frequency of the
5
calcification of the aneurysmal wal1 is mentioned by many authors and is extremely variable: 60 per cent, l3 50 per cent, 4,7 50 per cent of extraparenchymal aneurysm,13 33 to 50 per cent,12,23 over 25 per cent1 36 per cent, 24 27 per centZ 20 per cent5 and 10 per cent6 Calcifications of such lesions have been described in children eight years oldz6 and even six-and-one-half years old. 7 The calcification is the opaque image of the calcified aneurysmal sac. It is oval or circular in shape with a radiolucent center representing the lumen of the aneurysmal vessel. This may be completely opacified at arteriography depending on whether or not it contains a thrombus. The calcification is usually fine with well-defined contours. A calcified aneurysm which is partially thrombosed wil1 consequently be only partially opacified on arteriography. r’ A completely thrombosed aneurysm with calcified wal1 and radiolucent center on plain film may be confirmed only by angiography, in which case no contrast medium wil1 appear in the lumen.‘,27,28 Pictures may represent peripheral infarcts with scarring and retraction. 27 The classic aneurysmal calcification has many names. Perusal of the literature wil1 yield such terms as: ringlike, l2 shell-like, l2 or ring-shapedcalcification, 11a21 calcified ring appearance, 6 classic ring calcification fine wreath or ringlike, vascular type of calcification,14 semicircular, r1 “signet ring,” or “broken-wreath” calcification, 1 calcific shadow incompletely circular, egg shell in configuration, r3 “image en coquille d’oeuf brisé”2g “aspect en anneau brisé,“* “image en anneau brisé,“6 calcification en anneau brisé5 (broken ring), characteristic signet-ring or halo-shaped calcification,“‘and calcified, broken, wreathlike density.31 The signet-ring or broken-wreath calcification is, according to Kyle, ’ diagnostic of atherosclerotic extrarenal artery aneurysm. These calcifications have important characteristics. Usually, there is an interrupted area representing the point of origin of the artery. 5,7~14,26,2gOne must remember that the calcification may only be partial, in which case it is said to be an opaque fingernail print marking.7 The absente of interruption in a calcified ring raises other possible diagnoses. Progression in size of circular calcification between two consecutive radiographies may suggest aneurysm. Berneike and Pollock3’ have observed such a case over a two-year period. Differential diagnosis must be made with the following possibilities: renal calculus, 7~13ureteral
mesenteric nodes,4~7*1’4,14~‘H calculus, l3 calcified biliary stones, 7~19~14,2gadrenal cysts,33,3” pheochromocytoma (calcification in a fibrotic wal1 of’:1 cystic area within the tumor35 and calcification in a fibrotic wal1 of a tumor nodule35), calcified arteriosclerotic plaques in a tortuous renal 01’ splenic artery, 7 hematomas, 7*13*14,27,36perirenal of lumbar verteabscesses, l3 osteochondroma bra ‘,r3~14 intraperitoneal hydatid cysts, 7 renal hydatid cysts often accompanied by smaller ringlike calcified daughter cysts, 13,27congenital multicystic kidney, 37 and renal hamartoma. 3* One must also consider the possibihty of calcified aneurysm of other neighboring arteries such as the splenic, hepatic, pancreatic, or mesenteric arteries. 7 However, the most likely differential diagnosis is made with: benign simple renal cysts,“g renal cel1 carcinoma (calcified fibrous pseudocapsule surrounding several renal cel1 carcinoinas) 12*3g,40tuberculeus or nonspecific calcified lipogranuloma with abscesses, 7~14,3gsclerosiug fibrotic calcified pseudocapsule, renal cortical adenoma, renal cortical adenoma with hemorrhage and necrosis,41 cystic renal adenoma with degenerative changes and intramural calcificution, and congenital or acquired arteriovenous fistula. 7,27,42 Simple renal cysts or renal cel1 carcinotna should be forernost in our differential diagnosis because of their more common occurrencc. Daniel et al. 3g in a review of 2,709 cases of renal masses found that 1 to 2 per cent of simple cvsts and 10 per cent of renal cel1 carcinomas contained roentgenographically visible calcium. While peripheral egg-shell calcifications withoutcalciurn in the mass was usually associated with benign simple cysts, the risk of malignant disease was stil1 about 20 per cent. The site of annular calcium in the renal area is very important; hilar deposits suggest aneurysm whereas peripheral sites occur more frequently with tumoral lesions. Rarely aneurysmal calcific shadow wil1 project over the renal substance. 13*43 The incidence of calcification in renal artery aneurysm appeared to decrease in relation to the proximity of the aneurysm to the 80 per cent kidney substance. 4 Approximately of the renal artery aneurysms are extrarenal. ‘O While calcification in renal aneurysm is common. intrarenal aneurysms calcify less frequently than extrarenal aneurysms. *3 Intravenous pyelogram is essential to localize calcifications adequately. The collecting system is frequently compressed, displaced with image of indentation.12,44*45 If the compression is at the
classic signs of usual renal artery aneurysms. Aneurysms of peripheral arteries are rare and are present in periarteritis nodosa, angiitis of drug abuse, and rarely in malignant hypertension with necrotizing arteritis. 47 In this latter disease there are luminal irregularities and “pruning of the vascular bed” and disparity in the size of the centra1 and peripheral vessels.48 The vascular pattern of periarteritis nodosa and angiitis of drug abuse are indistinguishable roentgenographically, and in most instances the aneurysms when present range from 1 to 5 mm. in diameter. 47Despite the peripheral microaneurysms in our case, the size and situation of the aneurysms militate against the possibilities of angiitis of drug abuse or periarteritis nodosa. However, smal1 saccular aneurysm may be found at the bifurcation of the renal artery in the latter disease.12 In these cases of angiitis, the aneurysms are usually scattered and involve the interlobar, arcuate, and even interlobular arteries. 19*47~49-51 Moreover, other radiologie signs may be observed, and scattered areas ofnecrotizing arteritis may be present. The contour of the interlobar arteries may be irregular and a diminution in number may be apparent. The renal cortex is and Main aneuysm (1); satellite aneuysw irregular. 47 Scarring from thromboses FIGURE 6. (2 and 3). infarctions may be observed.19 Leary and Utz13 illustrated the angiographic pattern of a case with multiple intrarenal aneurysms, probably lobar and hilar veins. Microscopic examination congenital, in a boy thirteen years of age. of the walls of the aneurysms showed anticipated In our case, in spite of the radiologie identichanges: calcification and fibrosis of the wal1 fication of peripheral microaneurysms and a leading to a dissociation of the elastic and muscucertain degree of dilatation of the interlobar lar structures and atheromatous deposits at the arteries, we believe the patient had a congenital leve1 of the intima. polyaneurysmal dysplasia of the arterial bed of The congenital nature of the aneurysms was the right kidney. demonstrated by many findings: (1) At the leve1 of the aneurysmal dilatations, the atheromatous deposits were sharply limited to the dilated porPathologie jìndings tion of the artery. The elastic and muscular strucThe kidney weighed 200 Gm. The renal artery tures of the wal1 were interrupted as wel1 and was cannulated and injected under pressure with modified in an abrupt fashion at a junction spot a normal saline solution. An aneurysmal, saccular easily localized between the normal arterial wal1 dilatation 5 cm. in diameter was demonstrated on and that of the aneurysm, this contrary to prothe primary renal artery (Fig. 6). Satellite aneugressive changes of the arterial wal1 in proximity rysms corresponding to the previous radiologie of the aneurysm of atheromatous nature. description were observed at the hilar branches (2) The microscopic study demonstrated of the renal artery. These aneurysms were lined many unsuspected lesions of the arteries on gross with atheromatous deposits, while their walls examination and situated in the hilus area. These showed calcified plaques. were zones of muscular thinning and abrupt interruption of the elastic membranes, especially the Serial sections did not otherwise demonstrate internal one, accompanied secondarily by fibrosis evidente of anomalies of the venous wal1 or the and atheromatosis of the intima (Fig. 7A). In excretory ducts, although the proximal portion of brief these lesions represented aneurysms in the the ureter was slightly dilated. Also a significant state of formation. degree of dilatation was observed in the inter-
8
UROLOGY
/ JANUARY 1975 / VOLUME V, NUMBER 1
Aneurysm size varies from 1 to 2 cm. but rnay reach 10 to 12 cm. in diameter.’ Segmental ischemia of the kidney may also occur.‘I In some instances the local circulation peripheral to an aneurysm may be markedly reduced and the peripheral vasculature sparse. 23
FIGURE 5. Kidney specimen injected with radiopaque media shoting multiple aneurysms, microaneurysm of interlobular artery (arrow), and dilated interlobar artery (double arrowi.
pyeloureteral junction, hydronephrosis may ensue.7,16 Morin et a1.46 reported a case of unilateral cortical necrosis with the contralateral kidney bearing a calcified renal artery aneurysm with partial obstruction of the ureter. Often the kidney with the aneurysm may be smaller and even atrophic, but it may also be slightly larger than the contralateral organ.’ Angiography even though it affects a selected group of patients yields a frequency of 0.73 per cent,” 1.07 per cent,’ and 1.32 per cent6 of demonstrable renal artery aneurysms. Selective arteriography is the procedure of choice to diagnose and localize an aneurysm. Visibly calcified aneurysms on plain roentgenograms are no real indication of the total number of aneurysms in any given patientZ4 Other ipsilateral noncalcified aneurysms may be discovered. The aneurysms are usually saccular, and 60 to 70 per cent are located in the main renal artery or its bifurcation, or in a primary branch. l3 Aneurysms involving the smaller arterial branches, that is intrarenal, are uncommon.r4 Only 17 per cent of al1 reported cases of renal aneurysms were intrarenal.‘O Kyle in 1968l reported 20 such cases excluding microaneurysms of periarteriosa nodosa.
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/ JANUARY 1975 / VOLUME V, NUMBERl
Aneurysm may cause an incomplete and sometimes delayed filling of distal vessels as wel1 as prolonged retention of contrast material.“” Aortography cannot be omitted despite knowledge gained by selective renal arteriography because nearly half the cases of aneurysms are present bilaterally and sometimes in other organs as well. l2 They have been reported in the splenie. hepatic, gastroduodenal, superior mesenteric. and renal arteries” and sometimes multiply in some of these arteries.’ One case was reported in a one-month-old baby. l2 Congenital intrarenal aneurysms are usually saccular or fusiform, with or without calcification. Of the 50 reported cases of true intraparenchymal renal artery aneurysms, one-third were considered congenital in origin, one-third resulted from atherosclerosis, and one-third were associated with polyarteritis.‘” We believe that our case is radiologically compatible with a eongenital polyaneurysmal dysplasia of the kidney affecting only one organ of the abdomen. One has the classic shell-like calcification. Another has a calcified thrombosis in a secondary division of the renal artery, hut without the radiolucent center; the selective renal arteriography could not confirm the presence of circulating opaque material in the center of the calcified formation It could represent a calcified completely thrombosed aneurysm. The exaggerated size of the diseased kidney can be explained by the increased blood capacity of these aneurysms. There is an ischemic area in the upper pole resulting from important turbulente in the mam aneurysm thus delaying the filling of distal branches. The turbulente was recorded on cinefilm. It is probable that al1 the other aneurysms in the kidney are part of the same pathologie aneurysmal process. None of the arteries showed radiologie changes compatible with angiitis. By injecting the removed specimen with contrast material, it was possible to demonstrate the numerous aneurysms including peripheral microaneurysms (Fig. 5). Multiple smal1 kidney aneurysms usually occur in periarteritis nodosa or necrotizing angiitis associated with drug abuse. The differential diagnosis with these conditions was established by
FIGURE 7. (A) Wal1 of main aneuysm (1); hilar branches of renal artey (2); thinned out zone of arterial wal1 with interruption of internal and external elastic membranes (3); and jibrosis of intima (4) (Weigert x60). (B) lnterlobar artey: (1) parietal thinning with interruption of internal elastic membrane (Weigert x60).
(3) Certain interlobar arteries had otherwise presented parietal modifications not accompanied with fibrous reactions or atheromatous changes of the intima. These modifications were characterized by zones of muscular thinning or interrupted intemal elastic membranes, or both these phenomena (Fig. 7B). The latter lesions probably represented the pathologie basis of future aneurysmal dilatation. Management
The obvious decision is one of surgical intervention or of passive observation, considering the clinical complaints and the possible complications. The role of a renal aneurysm in arterial hypertension is difficult to assess. Some clinics specializing in arterial hypertension find a high inci(1.32 per cent), but dence of renal aneurysms they may represent a complication of the initial vascular disease, the arteriosclerosis with arterial hypertension causing the formation of aneurysms.6 However, as stated, thrombosis of an aneurysm can cause renal ischemia with resulting hypertension. However, the most important reason for surgical treatment is the danger of spontaneous rupture. The type and nature of the aneurysm, however, influences the frequency of rupture. McKiel, Graf, and Callahan in 196615 collected 32 cases of aneurysmal ruptures in the literature, 27 resulting in death. Al1 were cases of noncalcified lesion. Pregnancy is also a favoring condition to rupture. l Viville and others state that 90 per cent of the ruptures occurred in hyper-
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/ JANUARY 1975 / VOLUMEV,
NUMBERl
tensive patients. 5 Young patients, according to Gérard, are more likely to progress to eventual rupture;5 the same is true of symptomatic aneurysms. False intrarenal aneurysms are especially susceptible to spontaneous rupture. l” Ippolito and Le Veenz found that 25 per cent of al1 noncalcified aneurysms wil1 rupture, with a mortahty rate of 85 per cent. It becomes obvious that most aneurysms require surgical treatment, exceptions being smal1 (less than 1.5 cm.), solitary, calcified, asymptomatic, or extraparenchymal lesions in the normotensive middle-aged or older patient.3,‘5 Patel, Cormier, and Arthur53 go further by considering the possibility of conservative surgical intervention, making it clear that if the aneurysm, only, can be removed, it should be. The type of surgical procedure has evolved toward more conservative techniques. Atkinson54 considered nephrectomy as the choice procedure with a 6 per cent mortality rate as compared with 53 per cent in conservative procedures. However, as reconstructive procedures become more sophisticated, the mortality becomes more acceptable. Partial nephrectomy is preferred to total nephrectomy whenever feasible. Excision of saccular aneurysms with an arterial wal1 repair is the procedure’of choice if the lesion is on the pedicle. Fusiform aneurysms on the main trunk can be resected with an end to end reanastomosis. Other complications warrant surgical intervention and may include pain, persistent hematuria, infarction, and erosion of surrounding structures.
9
1656 Est. Montreal
133,
Sherbrooke
Quebec, (DR.
Canada
CHARRON)
References 1. KYLE, V. ,U.: Renal artery aneurysms, Assoc. J. 98: 815 (1968). 2. ABESHOUSE, B. S.: Renal aneurysms,
3. 4. 5.
6.
9.
10. 11.
12. 13.
14. 15.
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17.
18.
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