Intraabdominal

Pulmonary Sequestration

By M.D. Black, J. Bass, D.J. Martin, Ottawa, Ontario l A left upper quadrant fetal abdominal mass was detected at 24 weeks gestation. The mass was again confirmed in a postnatal ultrasound. Pathological analysis of the excised mass demonstrated an intraabdominal lung sequestration with Stocker type II congenital cystic adenomatoid malformation (CCAM). The sonographic characteristic of these lesions are those of a homogeneous echogenic mass with variable shape passing through or arising from the diaphragm. Surgical excision is recommended because of the uncertainty of the preoperative diagnosis and the possibility of malignant changes in CCAM. Copyright o 1991 by W.B. Saunders Company INDEX WORDS: chopulmonary

Pulmonary sequestration, foregut malformations.

extralobar;

bron-

P

ULMONARY sequestration, a rare congenital abnormality, has an estimated incidence of 0.15% to 1.7% in the general population.’ First described by Rokitansky and Rektorzik in 1861 as accessory pulmonary lobes, they were renamed by Pryce in 1964 and known since as pulmonary sequestrations.* However, it was Gerle et al, in 1968, who proposed the term “bronchopulmonary foregut malformation”” for the wide spectrum of anomalies, including this case report of extralobar intraabdominal lung sequestration. CASE

REPORT

A left upper quadrant fetal abdominal mass was found at 24 weeks gestation in a 2%year-old primigravida on a routine obstetrical ultrasound. Fetal growth remained normal and the mass continued to grow proportionately with the patient. Although pediatric surgical consultation was not requested, concerns of “rupturing the mass” during vaginal delivery resulted in elective cesarean section once fetal viability was determined. A postnatal abdominal ultrasound demonstrated an homogeneous pearshaped echogenic mass extending from beneath the diaphragmatic crus into the left paravertebral region and into the left upper quadrant of the abdomen. It measured approximately 3 x 4 x 3 cm (Fig 1) and was separate from the left adrenal gland, kidney, liver, and spleen. An upper gastrointestinal barium study failed to demonstrate any communications with the gastrointestinal tract, Computed tomography scan demonstrated the mass but did not provide additional information. A laparotomy was performed during the first week of life and a “pink’ mass resembling lung tissue was found just below the diaphragm anterior to the pancreas, posterior to the stomach and the left lobe of liver. It was separate from the spleen and left adrenal gland. Venous drainage occurred via the left gastric vein as well as to the dorsum of the pancreas. The main arterial supply was from the abdominal aorta. The left hemidiaphragm was normal. The mass was excised without difficulty and the patient was discharged home after an uneventful postoperative course. The pathological examination of the mass was that of a sequestered extralobar lung segment containing diffuse cystic spaces Journatoffediatric

Surgery,

Vol26,

No 12 (December),

1991: pp 1381-1383

and B.F. Carpenter

consistent malformation

with

Stocker Type II congenital (CCAM) (Fig 2).

cystic

adenomatoid

DISCUSSION

Although there are multiple embryologic theories capable of explaining the occurrence of complex congenital fistulae involving the tracheobronchial tree and upper gastrointestinal tract, no single theory proposed can account for all the recognized abnormalities that have been reported. It appears that malformation of the embryonic foregut is responsible for a wide spectrum of abnormalities, including pulmonary sequestration. Uncomplicated pulmonary sequestrations may theoretically result from ectopic pulmonary budding,4,’ fetal pulmonary infections6 as well as primary pulmonary vascular anomalies.’ The usual location for such abnormalities is in the thorax; intraabdominal occurrences have rarely been described.‘,’ It is possible that a pulmonary bud that traverses the diaphragmatic defect prior to embryologic closure will remain in close proximity to the diaphragm,’ as illustrated in the case presented. In a previous, similar case in this institution, the sequestered lobe was found embedded in the right hemidiaphragm (Saucy P: Personal communication, 1989). Extralobar intrathoracic sequestrations may be discovered incidentally during repair of a congenital diaphragmatic defect, while investigating other congenital abnormalities, or on chest roentgenogram performed for other medical reasons. Associated congenital anomalies are frequent (occurring in approximately 50%) and may be lethal in nature.“‘.” Although complex bronchopulmonary foregut anomalies with persistent fistula between the respiratory and gastrointestinal systems may result in infection and mediastinal shift from cystic overinflation and tension, such serious complications are unlikely in true extralobar sequestration.

From the Departments of Surgery, Radiology, and Pathology, Children S Hospital of Eastern Ontario, University of Ottawa, Ottawa, Ontario. Presented at the 22nd Annual Meeting of the Canadian Association of Paediattic Stageons, St John’s, Newfoundland, August 22-25, 1990. Address reprint requests to J. Bass, MD, Department of Surgery, Children’s Hospital of Eastern Ontario, 401 Smyth Rd, Ottawa, Ontario KIH SLI, Canada. Copyright 0 1991 by W.B. Saunders Company 0022-346819112612-0007$03.00/O 1381

BLACK

Fig 1. Postnatal the left kidney.

ultrasound

demonstrating

the mass

superior

ET AL

to

The rare development of high-output failure from a significant arteriovenous malformation in the sequestration” has been described in intralobar rather than extralobar sequestration. Although diagnostic angiography can be performed relatively safely through the umbilical vessels at birth, less invasive techniques that require little or no radiation exposure such as abdominal ultrasonography may prove as informative. The sonographic features of the present lesion as well as the ones described in the literature’,’ are those of a homogeneous echogenic mass with variable shape passing through or arising from the diaphragm. In the present patient, the presumptive diagnosis of such a lesion was made because of the sonographic similarities noted in a previous case of intraabdominal sequestration as well as the visualisation of normal adrenal glands. The sonographic diagnosis of other lesions such as neuroblastoma, teratoma, and foregut duplication should be considered when heterogeneity and calcifications are observed, especially with the failure to demonstrate normal adrenal glands. In the few reported cases of intraabdominal sequestration, neuroblastoma was the first diagnosis considered.‘,’ Expectant management has been practiced with uncomplicated extralobar intrathoracic pulmonary sequestrations in the adult and pediatric population.’

Fig 2. Lung section showing “back-to-back” cystic strutures lined by ciliated columnar epithelium, typical of CCAM type II. (Hematoxylinphloxine-saffranin, original magnification x110.)

Unless accurate initial diagnosis can be made, surgical management should be advocated in patients with intraabdominal extralobar sequestrations. Furthermore, malignant potential of CCAM of the lung (present in this case) has been reported.‘3,14 Unlike extralobar intrathoracic sequestrations, the incidence and the natural history of intraabdominal sequestrations are unknown. With the routine use of obstetrical ultrasound, difficult decisions pertaining to the management of recognized antenatal fetal abnormalities will be encountered more frequently. Accurate identification of the lesion is ideal and interdisciplinary consultation, in particular with a pediatric surgeon, is necessary to avoid inappropriate surgical or obstetrical interventions.

REFERENCES 4. Nikaidoh H, Swenson 0: The ectopic origin of the right main bronchus from the esophagus: A case of pneumonectomy in a neonate. J Thorac Cardiovasc Surg 62:151-160,197l 5. Blesovsky A: Pulmonary sequestration. A report of an unusual case and review of the literature. Thorax 22:351-357,1967 6. Gebauer PW, Mason CB: Intralobar pulmonary sequestrations associated with anomalous pulmonary vessels: A nonentity. Dis Chest 30:282-288, 1959

1. Weinbaum PJ, Bors-Koefoed R, Green K, et al: Antenatal sonographic findings in a case of intra-abdominal pulmonary sequestrations. Obstet Gynecol73:860-861,1989 2. Shamji FM, Sachs HJ, Perkins DG: Cystic disease of the lungs. Surg Clin North Am 68:581-620,1988 3. Gerle RD, Jaretzki A III, Ashley CA, et al: Congenital bronchopulmonary foregut malformation. N Engl J Med 278:14131419,1968

INTRAABDOMINAL

PULMONARY

SEQUESTRATION

7. Sade RM, Clouse M, Ellis FH Jr: The spectrum of pulmonary sequestration. Collective review. Ann Thorac Surg 18:644-658, 1974 8. Mariona F, McAlpin G, Zador I, et al: Sonographic detection of fetal extrathoracic pulmonary sequestration. J Ultrasound Med 5:283-285, 1986 9. DeParedes CG, Pierce WS, Johnson DG, et al: Pulmonary sequestration in infants and children: A 20-year old experience and review of the literature. J Pediatr Surg 5:136-147, 1970 10. Ryckman FC, Rosenkrants JG: Thoracic surgical problems in infancy and childhood. Surg Clin North Am 65:1423-1454, 1985

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11. Luck SR, Reynolds M, Raffensperger JG: Congenital bronchopulmonary malformations. Curr Prob Surg 23:250-314,1986 12. Levine MM, Nude1 DV, Gootman N, et al: Pulmonary sequestration causing congestive heart failure in infancy: A report of two cases and review of literature. Ann Thorac Surg 34:581-585, 1982 13. Sheffield EA, Addis BJ, Corrin B, et al: Epithelial hyperplasia and malignant change in congenital lung cysts. J Clin Pathol 40:612-614, 1987 14. Ueda K, Gruppo R, Unger F, et al: Rhabdomyosarcoma of lung arising in congenital cystic adenomatoid malformation. Cancer 40:383-388, 1977

Intraabdominal pulmonary sequestration.

A left upper quadrant fetal abdominal mass was detected at 24 weeks gestation. The mass was again confirmed in a postnatal ultrasound. Pathological an...
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