©
197'?
T\e 'Nilliams & Vlilkins
PREOPERATIVE DIAGNOSIS
RENAL ANGIOMYOLIPOIVIA
MICHAEL BARON, ELLIOT LEITER AND HERBERT BRENDLER From the Department of Urology, Mount Sinai Medical Center, New York, New York
ABSTRACT
Six cases of renal angiornyoliporna are reviewed. In 5 of these 6 cases a characteristic radiolucent fat sign was present overlying the renal mass. In 10 cases of hypernephroma selected only on the basis of a tissue diagnosis and the availability of a pre-injection scout film this sign was not present. The recent literature is reviewed on the radiographic diagnosis of angiomyolipoma. We conclude that angiography is not reliable in the differentiation of angiomyolipoma from hypernephroma. However, demonstration of a radiolucency on the pre-injection scout film is virtually pathognomonic of angiomyolipoma. Tomographic cuts without contrast injection may increase diagnostic accuracy. CASE REPORTS
Recently, considerable attention has been focused on the difficulties encountered in the diagnosis of renal angiomyolipomas. Retrospective review of pre-injection scout films from 2 recent cases at this institution prompted us to study our
Case 1. An excretory urogram (IVP) of a 66-year-old woman with recurrent cystitis revealed a right renal cyst. In March 1975 the patient suffered fever, nausea and vomiting, as well
Fm. 1. Case 1. A, IVP demonstrates right renal mass (arrows). B, pre-injection scout film demonstrates radiolucency overlying renal mass (arrows).
series of renal angiomyolipomas. The 2 patients reported on were believed to have had a hypernephroma preoperatively but pathologic examination of the excised kidney revealed angiomyolipoma in each case. Review of the pre-injection scout film after the surgical procedure and pathologic diagnosis showed a previously unappreciated radiolucency overlying the mass. This fact prompted a review of the literature to determine how often one can expect to find a radiolucent density on a flat film with angiomyolipoma and whether this finding was ever seen with hypernephroma. Accepted for publication September 3, 1976.
as right hip and right lower quadrant pain. An IVP again revealed a large right renal mass (fig. I, A). Angiography and venacavography suggested hypernephroma but nephrectomy revealed angiomyolipoma. Review of the pre-injection scout film revealed irregular areas of radiolucency not corresponding to bowel gas patterns overlying the mass (fig. 1, B). Case 2. A 76-year-old white man presented with symptoms of benign prostatic hypertrophy. An IVP (fig. 2, A) and selective renal angiography (fig. 2, B) revealed an avascular upper pole mass. Although the possibility of an avascular hypernephroma was considered preoperatively nephrectomy revealed angiomyolipoma. On postoperative review of the pre-injection 701
702
BARON, LEITER AND BRENDLER
Fm. 2. Case 2. A, IVP demonstrates right renal mass (arrows). B, selective renal angiogram demonstrates a vascular right renal mass Review of pre-injection scout films done in 16 cases of renal masses* Diagnosis Pt. Preop. BR LU
AL HM JF VE MF JL MH VK AC ML MB KD
NK OB
Angiomyolipoma Hypernephroma Angiomyolipoma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma
Postop. Angiomyolipoma Angiomyolipoma Angiomyolipoma Angiomyolipoma Angiomyolipoma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma
Radiolucency on Scout Film Yes Not available Yes Yes Yes Yes No No No No No No No No No No
* All patients except A. L. were subjected to nephrectomy.
Fm. 3. Case 2. Pre-injection scout film demonstrates radiolucency within right renal mass (open arrows).
scout film an irregular area of radiolucency not corresponding to bowel gas patterns was seen overlying the mass (fig. 3). METHOD AND RESULTS
Ten cases of hypernephroma selected on the basis of tissue diagnosis alone and in which a pre-injection scout film was
available were examined for radiolucency on the pre-injection film. The flat plates in our 6 most recent angiomyolipomas were reviewed likewise. These results are summarized in the table. In 5 of 6 cases of angiomyolipomas the pre-injection scout films were available. In 4 of these 5 cases radiolucencies not corresponding to bowel gas patterns overlying the mass were noted on the pre-injection scout films. In 1 of the 5 cases radiolucency was present over the mass and a previous nephrectomy for angiomyolipoma in the opposite kidney supported the clinical diagnosis of angiomyolipoma. In none of the cases of hypernephroma was a radiolucency found overlying the mass. DISCUSSION
Renal angiomyolipoma was first described in 1880 by Bourneville and Brissard. 1 The gross appearance, benign behavior and clinical presentation of the growth have been de-
scribed, In_ 1966 Crosett first described the ance of ill-defined radiot:ranslucent areas of fat in cases of angiomyolipoma associated with tuberous sclerosis, 2 However, in the 2 largest reviews of this lesion (comprising 182 angiomyolipomas) 3 ' "the diagnosis was not made preoperatively in a single case, Vl!hile numerous cases have been reported in which conservative management, such as open renal biopsy, wedge resection or partial nephrectomy, or no surgical intervention was done, in none of them was the method of preoperative diagnosis stated," The angiographic appearance of an angiomyolipoma has been reported extensively, In fact, some investigators have stated that renal angiography is the single most helpful diagnostic test in this condition, n The so-called characteristic multiple arterial aneurysms, the whorled "onion-peel" appearance seen during the venous phase, and a sharp margination and confusing semi-response to epinephrine have been submitted as diagnostic for angiomyolipoma, However, most investigators have found these pathognomonic diagnostic angiographic findings to be unreliable, Not only are they absent in many patients with pathologically proved angiomyolipoma but even in the presence of all of these findings the kidney has been found on occasion to contain a hypernephroma,', 8 In fact, Owman takes an opposite stand and states that a malignant diagnosis cannot be excluded angiographically and that a correct preoperative diagnosis can be made only when the lesion is suspected and the appearance of radio lucent fat areas on a plain roentgen examination are demonstrated, 9 The radiolucent fat sign was first discussed by Windholz with reference to a retroperitoneal lipoma, 10 Khilnani and Wolf believe that the roentgen features of renal lipomas are sufficiently clear cut to warrant a correct preoperative diagnosis in almost all cases of angiomyolipoma, 11 However, in our review of the literature we were able to find only 4 cases in which the author had a suspicion preoperatively that the mass was an angiomyolipoma on the basis of radiolucency on the scout film and then confirmed their diagnostic impressions by open renal biopsy, 12- " Becker and associates state that in their small series, even in retrospect, the finding ofradiolucency on the scout film is present in only 9 per cent of the patients, I(; The presence of a radiolucent fat sign is, of course, dependent upon the amount of fat contained within the hamartoma, Therefore, it may be absent in many patients, When minimal amounts of fat are present the radiolucencies may not be appreciated on a flat film but may become evident with tomography, Therefore, it must be supposed that pre-injection tomographic cuts might increase the frequency vvith which such radiolucencies within a mass would be demonstrated, It is safe to assume that in the 2 cases presented herein nephrectomy might have been avoided if tomographic cuts had been obtained without contrast injection, A logical extension of this would be that preoperative ,,-A,~A=-A~'A" without contrast ,n,ePAhn,n should be a part Of the LU,CUSHU:OLJ,l, evaluation of all cases of renal mass lesions, Our rd-rOQrns,+,mo studies that radiolucency on a scout film is a common finding angiomyolipomas and a most uncommon finding with malignant renal lesions, There will be circumstances in which nephrectomy is indicated in the management of angiomyolipoma but more conservative therapy, such as open renal biopsy, frozen section and partial nephrectomy, will often suffice if this condition is suspected initially, Tomographic cuts without contrast injection in all
c.ases of Qa1,:n,o,-1-'°,,; renal rnass lesions lead to a l_TIOre frequent diagnosis of ~'''"'"',rn'"' UH ,-,---M·•-A vve believe that the least µuwt,,u,ceu obtained in the diagnostic study ofrenal masses, the pre-injection scout film of the IVP or the arteriogram, may be the least appreciated and possibly the most significant study obtained, SUMMARY
Angiomyolipomas have been diagnosed preoperatively on rare occasions, Consequently, many patients with this benign tumor undergo unnecessary nephrectomy, We have reviewed a series of patients with angiomyolipomas and hypemephromas, All 5 patients with angiomyolipomas in whom a preinjection scout film was available demonstrated a characteristic radiolucent fat sign on the scout film, whereas this finding was never seen in patients with hypernephromas, The preinjection scout film should be reviewed for this pathognomonic feature in all patients with renal masses, Nephrotomography without contrast injection is recommended as a basic study in the diagnostic evaluation of all cases of renal masses, If present, angiomyolipoma can be suspected preoperatively and a renal biopsy should be obtained, thereby facilitating parenchymal conserving procedures when indicated, REFERENCES
L Long, W, W,, Jr, and Lynch, K, M,, Jr,: Angiolipomas: a case report, J, UroL, 106: 177, 197L 2, Crosett, AD,, Jr,: Roentgenographic findings in the renal lesion of tuberous sclerosis, Amer, J, Roentgen,, 98: 739, 1966, 3, Farrow, G, M,, Harrison, E, G,, Jr,, Utz, D, C, and Jones, D, R: Renal angiomyolipoma, A clinicopathologic study of 32 cases, Cancer, 22: 564, 1968, 4, Vasko, J, S,, Brockman, S, IC and Bomar, R L,, Renal angiorny-
olipoma: a rare case of spontaneous massive retroperitoneal hemorrhage, Ann, Surg,, 161: 577, 1965, 5, Hajdu, S, L and Foote, F, W,, Jr,: Angiomyolipoma of the kidney: report of 27 cases and review of the literature, J, UroL, 102: 396, 1968, 6, Ma, I'vL KG, and Chan, KW,: Renal angiomyolipoma-report of 5 cases, Brit, J, UroL, 46: 481, 1974, 7, Brendler, ff, Maguire, J, W, and Mitty, H, A,: Angiographic characteristics of renal hamartoma, BriL J, UroL, 43: 674, 197L 8, Siibiger, M, L, and Peterson, C, C,, Jr,: Renal angiomyolipoma: its distinctive angiographic characteristics, J, UroL, 106: 363, 1971, 9, Owman, T,: Renal angiomyolipoma versus renal carcinoma, Is
an angiographic differential diagnosis possible? Fortschr, Geb, Roentgenstr, Nuklearmed,, 121: 315, 1974. 10, Windholz, F,: Roentgen diagnosis of retroperitoneal liporna, Amer, J, Roentgen,, 56: 594, 1946. l L Khilnani, M. T, and 1Nolf, B, S,: Hamartolipoma of the kidney; clinical and roentgen features, Amer, J, Roentgen,, 86: 830, 196L
Adelman, B, P,: gen,, 95: 13, Hendricks, K 12,
of the kidney, Amer, J, Roent-
1973,
14, McCullough, D, L, Renal hamartoma, Current rmwFnt~ nosis and surgical management, Urology, 4: 235, 15, McCullough, D, L,, Scott, R, Jr, and Seybold, H, M,: Renal angiomyolipoma (hamartoma): review of the literature and report of 7 cases, J, UroL, 105: 32, 197L 16, Becker, J, A,, Kinkhabwala, M,, Pollack, H, and Bosniak, !\IL: Angiomyolipoma (hamartoma) of the kidney, An angiographic review, Acta RadioL, Diagn,, 14: 561, 1973,
197'?
T\e 'Nilliams & Vlilkins
PREOPERATIVE DIAGNOSIS
RENAL ANGIOMYOLIPOIVIA
MICHAEL BARON, ELLIOT LEITER AND HERBERT BRENDLER From the Department of Urology, Mount Sinai Medical Center, New York, New York
ABSTRACT
Six cases of renal angiornyoliporna are reviewed. In 5 of these 6 cases a characteristic radiolucent fat sign was present overlying the renal mass. In 10 cases of hypernephroma selected only on the basis of a tissue diagnosis and the availability of a pre-injection scout film this sign was not present. The recent literature is reviewed on the radiographic diagnosis of angiomyolipoma. We conclude that angiography is not reliable in the differentiation of angiomyolipoma from hypernephroma. However, demonstration of a radiolucency on the pre-injection scout film is virtually pathognomonic of angiomyolipoma. Tomographic cuts without contrast injection may increase diagnostic accuracy. CASE REPORTS
Recently, considerable attention has been focused on the difficulties encountered in the diagnosis of renal angiomyolipomas. Retrospective review of pre-injection scout films from 2 recent cases at this institution prompted us to study our
Case 1. An excretory urogram (IVP) of a 66-year-old woman with recurrent cystitis revealed a right renal cyst. In March 1975 the patient suffered fever, nausea and vomiting, as well
Fm. 1. Case 1. A, IVP demonstrates right renal mass (arrows). B, pre-injection scout film demonstrates radiolucency overlying renal mass (arrows).
series of renal angiomyolipomas. The 2 patients reported on were believed to have had a hypernephroma preoperatively but pathologic examination of the excised kidney revealed angiomyolipoma in each case. Review of the pre-injection scout film after the surgical procedure and pathologic diagnosis showed a previously unappreciated radiolucency overlying the mass. This fact prompted a review of the literature to determine how often one can expect to find a radiolucent density on a flat film with angiomyolipoma and whether this finding was ever seen with hypernephroma. Accepted for publication September 3, 1976.
as right hip and right lower quadrant pain. An IVP again revealed a large right renal mass (fig. I, A). Angiography and venacavography suggested hypernephroma but nephrectomy revealed angiomyolipoma. Review of the pre-injection scout film revealed irregular areas of radiolucency not corresponding to bowel gas patterns overlying the mass (fig. 1, B). Case 2. A 76-year-old white man presented with symptoms of benign prostatic hypertrophy. An IVP (fig. 2, A) and selective renal angiography (fig. 2, B) revealed an avascular upper pole mass. Although the possibility of an avascular hypernephroma was considered preoperatively nephrectomy revealed angiomyolipoma. On postoperative review of the pre-injection 701
702
BARON, LEITER AND BRENDLER
Fm. 2. Case 2. A, IVP demonstrates right renal mass (arrows). B, selective renal angiogram demonstrates a vascular right renal mass Review of pre-injection scout films done in 16 cases of renal masses* Diagnosis Pt. Preop. BR LU
AL HM JF VE MF JL MH VK AC ML MB KD
NK OB
Angiomyolipoma Hypernephroma Angiomyolipoma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma
Postop. Angiomyolipoma Angiomyolipoma Angiomyolipoma Angiomyolipoma Angiomyolipoma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma Hypernephroma
Radiolucency on Scout Film Yes Not available Yes Yes Yes Yes No No No No No No No No No No
* All patients except A. L. were subjected to nephrectomy.
Fm. 3. Case 2. Pre-injection scout film demonstrates radiolucency within right renal mass (open arrows).
scout film an irregular area of radiolucency not corresponding to bowel gas patterns was seen overlying the mass (fig. 3). METHOD AND RESULTS
Ten cases of hypernephroma selected on the basis of tissue diagnosis alone and in which a pre-injection scout film was
available were examined for radiolucency on the pre-injection film. The flat plates in our 6 most recent angiomyolipomas were reviewed likewise. These results are summarized in the table. In 5 of 6 cases of angiomyolipomas the pre-injection scout films were available. In 4 of these 5 cases radiolucencies not corresponding to bowel gas patterns overlying the mass were noted on the pre-injection scout films. In 1 of the 5 cases radiolucency was present over the mass and a previous nephrectomy for angiomyolipoma in the opposite kidney supported the clinical diagnosis of angiomyolipoma. In none of the cases of hypernephroma was a radiolucency found overlying the mass. DISCUSSION
Renal angiomyolipoma was first described in 1880 by Bourneville and Brissard. 1 The gross appearance, benign behavior and clinical presentation of the growth have been de-
scribed, In_ 1966 Crosett first described the ance of ill-defined radiot:ranslucent areas of fat in cases of angiomyolipoma associated with tuberous sclerosis, 2 However, in the 2 largest reviews of this lesion (comprising 182 angiomyolipomas) 3 ' "the diagnosis was not made preoperatively in a single case, Vl!hile numerous cases have been reported in which conservative management, such as open renal biopsy, wedge resection or partial nephrectomy, or no surgical intervention was done, in none of them was the method of preoperative diagnosis stated," The angiographic appearance of an angiomyolipoma has been reported extensively, In fact, some investigators have stated that renal angiography is the single most helpful diagnostic test in this condition, n The so-called characteristic multiple arterial aneurysms, the whorled "onion-peel" appearance seen during the venous phase, and a sharp margination and confusing semi-response to epinephrine have been submitted as diagnostic for angiomyolipoma, However, most investigators have found these pathognomonic diagnostic angiographic findings to be unreliable, Not only are they absent in many patients with pathologically proved angiomyolipoma but even in the presence of all of these findings the kidney has been found on occasion to contain a hypernephroma,', 8 In fact, Owman takes an opposite stand and states that a malignant diagnosis cannot be excluded angiographically and that a correct preoperative diagnosis can be made only when the lesion is suspected and the appearance of radio lucent fat areas on a plain roentgen examination are demonstrated, 9 The radiolucent fat sign was first discussed by Windholz with reference to a retroperitoneal lipoma, 10 Khilnani and Wolf believe that the roentgen features of renal lipomas are sufficiently clear cut to warrant a correct preoperative diagnosis in almost all cases of angiomyolipoma, 11 However, in our review of the literature we were able to find only 4 cases in which the author had a suspicion preoperatively that the mass was an angiomyolipoma on the basis of radiolucency on the scout film and then confirmed their diagnostic impressions by open renal biopsy, 12- " Becker and associates state that in their small series, even in retrospect, the finding ofradiolucency on the scout film is present in only 9 per cent of the patients, I(; The presence of a radiolucent fat sign is, of course, dependent upon the amount of fat contained within the hamartoma, Therefore, it may be absent in many patients, When minimal amounts of fat are present the radiolucencies may not be appreciated on a flat film but may become evident with tomography, Therefore, it must be supposed that pre-injection tomographic cuts might increase the frequency vvith which such radiolucencies within a mass would be demonstrated, It is safe to assume that in the 2 cases presented herein nephrectomy might have been avoided if tomographic cuts had been obtained without contrast injection, A logical extension of this would be that preoperative ,,-A,~A=-A~'A" without contrast ,n,ePAhn,n should be a part Of the LU,CUSHU:OLJ,l, evaluation of all cases of renal mass lesions, Our rd-rOQrns,+,mo studies that radiolucency on a scout film is a common finding angiomyolipomas and a most uncommon finding with malignant renal lesions, There will be circumstances in which nephrectomy is indicated in the management of angiomyolipoma but more conservative therapy, such as open renal biopsy, frozen section and partial nephrectomy, will often suffice if this condition is suspected initially, Tomographic cuts without contrast injection in all
c.ases of Qa1,:n,o,-1-'°,,; renal rnass lesions lead to a l_TIOre frequent diagnosis of ~'''"'"',rn'"' UH ,-,---M·•-A vve believe that the least µuwt,,u,ceu obtained in the diagnostic study ofrenal masses, the pre-injection scout film of the IVP or the arteriogram, may be the least appreciated and possibly the most significant study obtained, SUMMARY
Angiomyolipomas have been diagnosed preoperatively on rare occasions, Consequently, many patients with this benign tumor undergo unnecessary nephrectomy, We have reviewed a series of patients with angiomyolipomas and hypemephromas, All 5 patients with angiomyolipomas in whom a preinjection scout film was available demonstrated a characteristic radiolucent fat sign on the scout film, whereas this finding was never seen in patients with hypernephromas, The preinjection scout film should be reviewed for this pathognomonic feature in all patients with renal masses, Nephrotomography without contrast injection is recommended as a basic study in the diagnostic evaluation of all cases of renal masses, If present, angiomyolipoma can be suspected preoperatively and a renal biopsy should be obtained, thereby facilitating parenchymal conserving procedures when indicated, REFERENCES
L Long, W, W,, Jr, and Lynch, K, M,, Jr,: Angiolipomas: a case report, J, UroL, 106: 177, 197L 2, Crosett, AD,, Jr,: Roentgenographic findings in the renal lesion of tuberous sclerosis, Amer, J, Roentgen,, 98: 739, 1966, 3, Farrow, G, M,, Harrison, E, G,, Jr,, Utz, D, C, and Jones, D, R: Renal angiomyolipoma, A clinicopathologic study of 32 cases, Cancer, 22: 564, 1968, 4, Vasko, J, S,, Brockman, S, IC and Bomar, R L,, Renal angiorny-
olipoma: a rare case of spontaneous massive retroperitoneal hemorrhage, Ann, Surg,, 161: 577, 1965, 5, Hajdu, S, L and Foote, F, W,, Jr,: Angiomyolipoma of the kidney: report of 27 cases and review of the literature, J, UroL, 102: 396, 1968, 6, Ma, I'vL KG, and Chan, KW,: Renal angiomyolipoma-report of 5 cases, Brit, J, UroL, 46: 481, 1974, 7, Brendler, ff, Maguire, J, W, and Mitty, H, A,: Angiographic characteristics of renal hamartoma, BriL J, UroL, 43: 674, 197L 8, Siibiger, M, L, and Peterson, C, C,, Jr,: Renal angiomyolipoma: its distinctive angiographic characteristics, J, UroL, 106: 363, 1971, 9, Owman, T,: Renal angiomyolipoma versus renal carcinoma, Is
an angiographic differential diagnosis possible? Fortschr, Geb, Roentgenstr, Nuklearmed,, 121: 315, 1974. 10, Windholz, F,: Roentgen diagnosis of retroperitoneal liporna, Amer, J, Roentgen,, 56: 594, 1946. l L Khilnani, M. T, and 1Nolf, B, S,: Hamartolipoma of the kidney; clinical and roentgen features, Amer, J, Roentgen,, 86: 830, 196L
Adelman, B, P,: gen,, 95: 13, Hendricks, K 12,
of the kidney, Amer, J, Roent-
1973,
14, McCullough, D, L, Renal hamartoma, Current rmwFnt~ nosis and surgical management, Urology, 4: 235, 15, McCullough, D, L,, Scott, R, Jr, and Seybold, H, M,: Renal angiomyolipoma (hamartoma): review of the literature and report of 7 cases, J, UroL, 105: 32, 197L 16, Becker, J, A,, Kinkhabwala, M,, Pollack, H, and Bosniak, !\IL: Angiomyolipoma (hamartoma) of the kidney, An angiographic review, Acta RadioL, Diagn,, 14: 561, 1973,
