Intralobar Pulmonary Sequestration With Special Emphasis on Bronchial Communication 1 Mutsumasa Takahashi, M.D., Masato Ohno, M.D., Keikichi Mihara, M.D., Keiichi Matsuura, M.D., and Akinobu Sumiyoshi, M.D.
The radiologic and pathologic features of eight cases of intralobar pulmonary sequestration are reported. Special attention was given the communication between the cystic areasand the normal bronchial tree. Inthree of five surgical specimens, probing revealed such communications. Microscopically, the transition from the normal bronchus to the cysts revealed no inflammation to suggest fistulous communication secondary to infection. The possibility of preexisting congenital bronchocystic communications within the pulmonary sequestrations wastherefore suggested. INDEX TERMS:
Aorta, abnormalities • Lungs, abnormalities • Lungs, cysts
Radiology 114:543-549, March 1975
NTRALOBAR PULMONARY sequestration is a congenital disease characterized by nonfunctioning lung tissue having anomalous blood supply stemming from the systemic circulation (5, 7, 8, 10, 11). It is suspected on such roentgen findings as recurrent pulmonary infiltration and multiple cystic changes in the basal segments of the lower lobes. The diagnosis is confirmed by demonstrating an abnormal artery arising from the aorta or its branches and supplying the involved segment. The relationship of the normal bronchial tree to the cystic areas within the sequestration has not been described in detail. It has been reported that no connection exists between the normal bronchus and the multiple cysts of the sequestration, and bronchography is therefore expected to show failure of opaque material to enter the lesion (1). The occasional communication between the bronchi and the cystic lesions has been attributed to fistulae secondary to recurrent infections (5,
7, 8, 13). A review of our intralobar pulmonary sequestration material suggests, on the contrary, that the frequent
presence of air in the cystic lesion and an occasional communication between the bronchus and the lesion shown bronchographically can be attributed to a.congenital preexisting communication between the bronchus and the sequestration even though recurrent pulmonary infection may also play an etiologic role at times. MATERIAL AND METHODS
This report is of eight cases of intralobar pulmonary sequestration seen in our hospitals over a five-year period (TABLE I; Figs. 1-16). In all, angiography was performed to clarify abnormal findings on the chest radiographs. There were four patients of each sex, with ages ranging from five to 57 years. All but one had recurrent pulmonary infections: in CASE V a round lesion was seen on routine chest radiographs. Five patients underwent lobectomy. The radiographs of the 8 patients were reviewed in
Table I: Summary of Clinical and Radiologic Findings Age and Sex
Plain Chest Radiography and Tomography
Multiple cysts with fluid levels Multiple cysts
Multiple cysts Multiple cysts with fluid levels A round mass Multiple cysts with fluid levels Diffuse infiltration with cavities Multiple cysts with infiltration and fluid levels
...---Abnorrnal Artery---. Size Origin No. (mm)
Displacement and filling of cysts Displacement and filling of cysts Displacement Displacement and filling of cysts Displacement Displacement
Celiac a. Celiac a.
Displacement" Displacement and filling of cysts
Yes No No Yes
Abd. aorta Abd. aorta
Pulrn. vein and IVC Not shown Pulm. vein
Pulm. vein Pulm. vein
1 From the Department of Radiology (M. T.), Akita University School of Medicine, Akita, Japan, andthe Departments of Radiology (M. O.~ K. M., K. M.)andPathology (A. S.), Kyushu University School of Medicine, Fukuoka, Japan. Accepted for publication in September 1974. ah
MUTSUMASA TAKAHASHI AND OTHERS
Figs. 1-3 . CASE I. A 17-year-old Japanese youth withcomplaints of recurrent pulmonary infection in the rightlowerlobe since theage of ten years. Fig. 1. A posteroanterior radiograph of the chest shows a multicystic lesion with several air-fluid levels in the posterior basal segment of the right lowerlobe.
Fig. 2. A lateral bronchogram shows a segmental bronchus to the posterior basal segment with minimal dilatation and irregularity. At least two cysts have been filled from " normal" bronchi measuring 3 mm and 5 mm in diameter. These bronchi seem to communicate directly and uninterruptedly withthe multicysticlesion. Theremaining bronchi are displaced from the sequestration. Fig. 3. Selective angiogram. An abnormal artery. 7 mm in diameter, arises from the abdominal aorta slightly above the celiacaxis. enters the lesion via the diaphragm, and supplies a fine arterial network to the cysts. The pulmonary artery is filled by small communicating arterial networks andbranches spread within the pulmonary lesion. Venous drainage was via the pulmonary veins. detail. Surgical specimens were obtained, and small elastic catheters were used to probe the normal bronchi and openings in the cyst walls to demonstrate communications. Microscopic studies were made of the transitional zones between normal bronchi and cystic areas.
RESULTS The radiologic findings are summarized in TABLE I. Plain Radiographs with Laminagrams: In six of the eight patients there were multicystic lesions in the posterior or medial basal portions of the lower lobes, with air-fluid levels in the cysts of four. In the fifth case, there was a diffuse infiltrate of a lower lobe with several cavities. Another patient's lesion appeared as an ovoid tumor 5 cm in diameter in the basal segment of the left
lower lobe. Sequestration was present on the left in five patients; on the right in three. In only one did plain radiographs show an abnormal artery entering the lesion via the diaphragm. Bronchograms: In every instance, bronchi adjacent to the sequestrations were displaced by the latter in an arcuate fashion . In four of seven cases multiple cysts were filled with contrast medium. In two of these four the bronchi were approximately 5 mm in diameter and entered the cysts directly, showing to good advantage the communications between cysts and bronchi. In the other two patients, the communications were not observed, even though the cysts were filled with contrast material. Angiograms: In each of the eight patients , angiogra-
INTRALOBAR PULMONARY SEQUESTRA nON
Figs. 4-5. CASE I (Cont.). Fig. 4. A bronchogram of the surgical specimen shows filling of the cystic lesions directly from branches of the distal segmental bronchi. Multiple cysts within the lesion are interconnected by small channels or small intervening cysts. Multiple small bronchi were within the muiticystic lesion which was devoid of contents . The margin of the cystic lesion was not defined, and the transition between the sequestration and the normal lung was smooth. Fig. 5. Cut surface of a surgical specimen . A probe in the "normal" bronchus leads to a small cyst which, in turn, is connected with the largest cyst via a small channel. The abnormal artery penetrated the sequestration and distributed small branches to the cyst walls.
phy showed an abnormal artery entering the sequestration. These abnormal arteries arose from the abdominal and the thoracic aortas in three cases each, and from the celiac axis in two. There was one abnormal artery apiece, except in one instance in which three abnormal arteries arose from the thoracic aorta. The arteries ranged from 3 to 12 mm in diameter . Venous drainage was via the pulmonary vein in 6 patients; via the pulmonary vein and inferior vena cava in one, and not shown in one . Pathologic Observations: In three of five surgical specimens studied macroscopically, it was possible to locate the sequestrated lesions by tracing the normal bronchus. This indicated communications between the bronchi and the cysts . Usually, there were small openings in each cyst, some of which could be traced to the normal bronchus by probing with the aforesaid elastic catheter. Microscopic examination of the bronchocystic communication showed no evidence of a fistulous tract secondary to inflammatory change . The columnar and ciliated epithelium resting on the basement membrane
was continuous throughout the bronchial mucosa, the communication, and the cyst wall, as were the mucous glands in the mucosa, which remained intact. Also, the smooth-muscle fibers in the bronchus were continuous with those of the communication and the cyst. There was no marked acute inflammatory change or granulation tissue formation in the mucosa or submucosa of the communicating channel. CASE REPORTS
Reports of three typical cases are combined with the legends of Figures 1-16. DISCUSSION
Several reports describe opacification of the cystic areas on bronchography. Zelefsky (13) cited four reported cases wherein bronchography demonstrated filling of the cystic areas and added two similar cases. Kohler (5) also reported two such cases. Furthermore, the cystic areas in the pulmonary sequestration always
MUTSUMASA TAKAHASHI AND OTHERS
Fig. 6. CAse I (Cont.). Microscopic examination of the bronchocystic communication . X 35 The ciliated epithelium, basement membrane, and smooth-muscle layer are continuous from the "normal" bronchus to the cyst. The mucous glands are relatively normal. There was minimal fibrosis, but active inflammation was not seen adjacent to the bronchocystic communication . The arteries within the lesion possessed the structure of the elastic artery with intimal sclerosis, suggesting a systemic artery . C, cyst; B, bronchial branch .
contain air, presenting as multicystic pulmonary abnormalities. However, there has been no real explanation for the presence of air within the lesion or for the occasional bronchographic showing of filling of cystic spaces with contrast medium. Some authors believe that the communication between bronchi and cystic areas was the result of associated inflammation (8, 10, 13). Culiner and Wall (3) explained the presence of air in the sequestration by collateral interalveolar ventilation. In Pryce's series of eight cases (8) there were two with apparent congenital communications, but detailed pathologic evaluation was not included. Pulmonary sequestration with bronchial communication was even considered a separate clinical entity (5, 11). Because the inflammation frequently associated with this pulmonary lesion may induce a systemic blood supply, some authors questioned the existence of intrapul-
Figs . 7-11. CAse IV. were within normal limits.
A 5-year-old Japanese girl with a history of repeated episodes of pulmonary infection since birth. Laboratory data
Fig . 7. A posteroanterior radiograph of the chest demonstrates a multicystic lesion in the right lower lobe medially. with thin cyst walls. The largest cyst was 5 em in diameter. The lateral view showed the lesion posteriorly, in the posterior basal and medial basal segments of the right lower lobe. Several air-fluid levels are seen within the cysts. Fig . 8.
Anteroposterior bronchography reveals filling of several cysts. Most segmental bronchi are displaced laterally by the lesion. Continued on fof/owing page
INTRALOBAR PULMONARY SEQUESTRATION
monary sequestration as a specific disease entity (4). However, chronic or recurrent pulmonary infection usually receives its blood supply from the bronchial or intercostal arteries instead of from abnormally enlarged arteries from the aorta . Furthermore. pulmonary sequestration has been reported without associated infection (2,3). Although inflammation within the lesion may be noted in most cases, several of our findings suggest that the bronchocystic communications may be explained on the basis of a developmental anomaly. Pathologic examination of our cases showed the normal bronchus and the cyst in the lesion to be covered continuously with the ciliated epithelium. In addition, the basement membrane and bronchial smooth-muscle layers were continuous from the bronchus to the cyst. The mucous glands of the bronchus were present to the junction between the cyst and bronchus. There was no acute inflammation or marked granulation tissue formation in the bronchocystic junction. These observations strongly suggest a congenital preexisting communication between the cyst and the normal bronchus. Patients with pulmonary sequestration seek medical attention for repeated infections , such as recurrent pneumonia or lung abscesses. A ready explanation for recurrent infection is offered by the presence of a communication between the normal bronchus and the lesion (6). In the absence of a commun ication between the normal bronchus and the sequestration, infection can be explained only on the basis of local continuity from
Fig. 9. CASE IV (Cont.). Fig. 9. A thoracoabdominal aortogram in the anteroposterior projection shows an abnormal artery, 8 mm in diameter, arising from the proximal portion of the abdominal aorta, 2 to 3 cm above the celiac artery origin.!t enters the sequestration via the diaphragm . courses superiorly and to the right, enters the right lower lobe, and then branches into numerous small , tortuous vessels . Venous drainage was to the pulmonary vein .
the adjacent pulmonary tissue or by hematogenous spread . Infection via the normal bronchial tree can explain the pathogenesis of this inflammation better than
Figs. 10-11 . CASEIV (Cont.). Fig. 10. Cut surface of the surgical specimen. The lesion was in the medial basal segment of the right lower lobe and consisted of multiple cysts and gelatinous material. The posterior basal segment was intact. There was normal lung tissue within the lesion, and the transition from the sequestrated area to the normal lung tissue was gradual. Multiple small bronchi were also within the lesion . Probing of the bronchi of the medial basal segment revealed a communication between the cysts and the "normal " bronchi. Small openings on the inner surface of the cysts were traced to the adjoining cysts and "normal " bronchi. Fig. 11. A microscopic section of the transition from the " normal" bronchus to the cyst reveals that the ciliated epithelium, the basement membrane, and the smooth-muscle layer are continuous between the bronchi and the cysts . X 35 There was no definite acute inflammation or granulation tissue within the wall of the bronchocystic communication. The abnormal artery was of elastic type with intimal sclerosis, suggesting a systemic artery. C, cyst ; B, bronchial branch.
MUTSUMASA TAKAHASHI AND OTHERS
Figs. 12-15. CASE VIII. A 39-year-old woman was admitted for recurrent pneumonia in the left lower lobe . Physical examination disclosed moist rales over the left lower thorax posteriorly. The laboratory data were unremarkable. Fig. 12. A posteroanterior chest radiograph shows a diffuse infiltrate with a round configuration in the posterior aspect of the left lower lobe and a sm' radiolucency with an air-fluid level in the superior aspect of the lesion. Fig. 13. The lateral view of the chest demonstrates the lesion in the posterior basal segment. There is a cyst with an air-fluid Jevel. Chest films between episodes of infection revealed a multi cystic lesion . Tomography showed a similar appearance with an air-fluid level. Legend continued on following page
INTRALOBAR PULMONARY SEQUESTRATION
can contiguous or hematogenous spread, in view of the fact that the majority of pulmonary sequestrations show some form of infection . Our evidence is contrary to the previous concept that pulmonary sequestration is a pulmonary and arterial malformation with secondary bronchial changes (5, 7, 8, 11), for it indicates that this disease entity is a bronchial; pulmonary, and arterial malformation associated with occasional congenital communication between the cystic areas and the normal bronchi. More detailed investigations on a large number of cases are required for further elucidation of the pathogenesis of this disease. Department of Radiology Akita University School of Medicine Akita, Japan
REFERENCES 1. Bruwer AJ, Clagett OT, McDonald J: Intralobar bronchopulmonary sequestration . Am J RoentgenoI71:751 -761 , May 1954 2. Cooley JC: Intralobar bronchopulmonary sequestration: a report of three cases. Dis Chest 42:95-99, Jul 1962 3. Culiner MM, Wall CA : Collateral ventilation in "intralobar pulmonary sequestration": report of a case. Dis Chest 47:118-122, Jan 1965 4. Gebauer PW, Mason CB: Intralobar pulmonary sequestration associated with anomalous pulmonary vessels: a nonentity. Dis Chest 35:282-288, Mar 1959 5. Kohler R: Pulmonary sequestration . Acta Radiol [Diag] 8: 337-353,JuI1969 6. Marks C, Wiener SN, Reydman M: Pulmonary sequestration. Chest 61:255-257, Mar 1972 7. Pryce DM: Lower accessory pulmonary artery with intralobar sequestration of lung: a report of seven cases . J Pathol Bacteriol 58: 457-467,Jul 1946 8. Pryce OM, Sellors TH, Blair LG: Intralobar sequestration of lung associated with an abnormal pulmonary artery. Br J Surg 35: 18-29.Ju\ 1947 9. Saegesser F, Besson A: Extralobar and intralobar pulmonary sequestration of the upper and lower lobes: report of eleven cases including one case of the scimitar syndrome . Chest 63:69-73, Jan 1973 10. Simopoulos AP, Rosenblum OJ, Mazumdar H, et ai: intralobar bronchopulmonary sequestration in children: diagnosis by intrathoracic aortography. Am J Dis Child 97:796-804, Jun 1959
Fig. 16. CASE VIII (cont.). Cut surface of the surgical specimen. The lesion was in the posterior basal segment of the left lower lobe. Multiple cystic lesions in the sequestration were inter- : connected by small communicating channels or intervening cysts. Small segmental bronchial branches led to the cystic areas. Some of the cysts contained gelatinous material. One of the bronchial branches (2 small arrows) can be traced to the cyst (large arrow) . Microscopically, the communication between the bronchus and cyst showed continuous mucosa and submucosa with a normal-appearing ciliated epithelium , basement membrane, and smooth-muscle layer. There was no acute inflammation. 11. Spencer H: Pathology of the Lung. New York, Macmillan; Oxford , England, Pergamon, 1962 12. Takahashi M, Kawanami H, Nakagawa E, et al: Roentgen diagnosis of pulmonary sequestration. Rinsho Hosha 13:1020-1030, Dec 1968 13. Zelefsky MN, Janis M, Bernstein R, et al: Intralobar bronchopulmonary sequestration with bronchial communication. Chest 59:266-270, Mar 1971
Fig. 14. Lateral bronchography demonstrated direct filling of the largest cyst via a normal-appearing branch of the posterior basal segmental bronchus. There appeared to be direct communication between the cyst and the "normal" bronchus. The remaining bronchial branches were displaced laterally by the lesion. Fig. 15. A selective angiogram of the abnormal artery, 7 mm in its greatest diameter, shows that it arises directly from the distal portion of the thoracic aorta at the level of the eleventh thoracic vertebra and it distr ibutes numerous small branches to the left lower lobe lesion. There was filling of the pulmonary arterial branches via minute collateral arteries. Drainage was to the pulmonary vein.