Clinical Brief
Intra-Abdominal Extralobar Pulmonary Sequestration Presenting Antenatally as a Suprarenal Mass A.K. Singal, S. Agarwala, T. Seth 1, A.K. Gupta 2 and D.K. Mitra
Departments of Pediatric Surgery, 1Medical Oncology and 2Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India
Abstract. Extralobar pulmonary sequestration is a rare pulmonary parenchymal anomaly which rarely may be present in an intra-abdominal location. The authors report a case of intra-abdominal extralobar pulmonary sequestration which presented to us as an antenatally diagnosed suprarenal mass and was worked up as such. The diagnosis was revealed only at laparotomy. Intra-abdominal extralobar pulmonary sequestration should also be kept in differential diagnosis in cases of masses in the suprarenal location, especially on the left side. [Indian J Pediatr 2004; 71 (12) : 1137-1139]
E-real~:
[email protected] Key words : Extralobar pulmonary sequestration; Intra-abdominal; Antenatal diagnosis The antenatal identification of a fetal structural anomaly has become increasingly common as prenatal ultrasound (USG) has become a standard of antenatal care. A fetal intra-abdominal mass is one of the commonly detected such anomalies. The differential diagnosis in this setting ranges from hydronephrosis to a malignant neuroblastoma, the diagnosis can only be confirmed with surety postnatally. Extralobar pulmonary sequestration (EPS), a rare pulmonary parenchymal anomaly on occasions may be present in an intra-abdominal location; and given the availability of routine fetal USG these lesions can be picked up antenatally. Described herein is such an unusual occurrence where a supra-renal mass was noted at 26 weeks gestation and postnatally confirmed to be an EPS. CASE REPORT
A 36-year-old third gravida mother underwent antenatal USG at 26 weeks revealed a left supra-renal mass about 2.7x2.2 cm in size. The mass was echogenic and well circumscribed. Two repeat USG at 30 and 36 weeks showed a persistent mass, which remained less than 3 cm in size. Colour Doppler in the last study did not show any abnormal feeding vessel. She delivered a male baby weighing 3.2 kg at term by an uncomplicated vaginal delivery. Postnatal USG (Fig la) showed an echogenic left supra-renal mass, which was confirmed on CECT scan (Fig lb). Work-up for neuroblastoma including urinary catecholamine metabolites and MIBG scan were negative. Correspondence and Reprint requests : Dr. Sandeep Agarwala, Department of Pediatric Surgery,All India Institute of Medical Sciences,New Delhi-110029, India. Indian Journal of Pediatrics, Volume 71--December, 2004
The child underwent laparotomy at 3 months of age. A 3x3 cm reddish brown mass was found in left supra-renal location, separate from the left adrenal gland. There was a distinct large artery arising from the abdominal aorta just proximal to the celiac axis and supplying the mass. The mass was excised and a provisional diagnosis of EPS was made. Cut section showed a spongy solid mass with a few dilated veins and arteries. Post-operative period was uneventful. Histopathology examination showed lung parenchyma with fresh hemorrhage and mucus in bronchi lined by ciliated epithelium. DISCUSSION
Pryce coined the term 'sequestration' in 1946 to describe an anatomically separate p u l m o n a r y mass with anomalous blood supply. 1 These lesions do not communicate with the functional airway. Pulmonary sequestrations can be further divided into the extralobar type (25%) in which the lesion is surrounded by a separate pleural sac; and the intralobar type (75%) in which the pleura is shared with the native lung tissue. 2 These malformations result form the abnormal budding of the ventral region of the embryonic foregut (the future tracheobronchial tree) and are classified under the broad umbrella of bronchopulmonary foregut malformations.3,4 An intra-abdominal EPS is thought to develop just before the closure of the diaphragm such that the sequestered tissue is pinched off and trapped within the abdomen. The majority of the EPS have associated e x t r a p u l m o n a r y anomalies such as cardiac, gastrointestinal anomalies or diaphragmatic hernia, the last being the most common. 4,5 About 90% of the EPS occur in the left hemithorax, typically between the left 1137
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Fig. 1.(a). Postnatal ultrasound showing the left suprarenal mass (arrow). SPL = spleen, LK= Left Kidney. (b) Contrast enhanced CT scan showing the left suprarenal mass (arrow). l o w e r lobe a n d the d i a p h r a g m . A b o u t 10% are intraa b d o m i n a l in location and these are often discovered i n c i d e n t a l l y at a u t o p s y or at the time of s o m e other surgery. With routine USG examination of the fetus these anomalies have been discovered antenatally with increasing frequency. 6-1~The classical USG findings of sequestration include a sharply localized mass which is d i f f u s e l y e c h o g e n i c . E c h o g e n i c i t y r e s u l t s f r o m the multiple tissue interfaces presented to the USG beam2 TM Visualization of a systemic feeding vessel on colour D o p p l e r or MRI f r o m the aorta virtually clinches the diagnosis, t h o u g h this m a y be difficult to demonstrate antenatally. The differential d i a g n o s e s of a n t e n a t a l l y detected supra-renal mass include neuroblastoma, adrenal h e m o r r h a g e , d u p l i c a t i o n cyst, d u p l e x k i d n e y , l y m h a n g i o m a , h e m a n g i o m a s a n d t e r a t o m a . As the possibility of a malignancy is real, postnatal evaluation must be done expeditiously. Postnatal evaluation should i n c l u d e a c h e s t x - r a y to r u l e o u t a n y i n t r a t h o r a c i c extension, USG a n d / o r CT or MRI to further delineate the a n a t o m y and biochemical w o r k - u p for neuroblastoma. Colour flow Doppler studies and MRI m a y be useful for d e m o n s t r a t i n g a b e r r a n t b l o o d s u p p l y , b u t are n o t essential. A vigilant surgeon should be able to identify such blood supply at the time of surgery. Surgical excision of the s e q u e s t e r e d l u n g m a s s is necessary in intralobar variety due to high incidence of r e c u r r e n t infections; w h i l e in p a t i e n t s w i t h EPS it is usually done determine the nature of the mass. As in the present case it is often difficult to reach the diagnosis on the basis of imaging alone. Secondly as the co-existence of congenital cystadenoamtoid malformation is known, and m a l i g n a n c y h a s b e e n r e p o r t e d in a case of s u c h a m a l f o r m a t i o n , it is w i s e to r e s e c t the lesion. 1~ Complications resulting f r o m a c o m m u n i c a t i o n of the 1138
aberrant lung tissue with gastro-intestinal tract m a y also occur and lead to unnecessary morbidity. 3 Early correct diagnosis and surgical t r e a t m e n t of these lesions are essential to ensure the well being of affected child.
CONCLUSION The infra-diaphragrnatic type of EPS is rare and as such is not often c o n s i d e r e d in the differential d i a g n o s i s of antenatally detected supra-renal mass. Inclusion of this benign entity in the list of possible diagnosis is important for antenatal parental counseling and planning p r o p e r postnatal work-up.
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characterization of a left suprarenal mass. Abdomin Imaging 2001; 26 : 28-31. 11. Rosado-de-Christensen ML, Frazier AA, Stocker JT et al. Extralobar sequestration: Radiologic-pathologic correlation. Radiographics 1993; 13 : 425-441. 12. Udea K, Gruppo R, Unger F et al. Rhabdomyosarcoma of lung arising in congenital cystic adenomatoid malformation. Cancer 1977; 40: 383-388.
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