Case of the Month from the Afip

Abstract

FEW CLINICAL and radiological problems require such prompt attention as the discovery of an abdominal mass in the infant or young child. These may often attain great size without significant symptoms and may be discovered accidentally by the parent or on a routine physical examination by the physician. Lack of symptoms does not indicate a benign lesion, since approximately 20 per cent of childhood cancers are represented by Wilms's tumor or neuroblastoma (5). These two tumors, together with unilateral hydronephrotic kidney and unilateral multicystic kidney, comprise the bulk of abdominal masses found in the early pediatric age group. The case this month is one of the few reported cases in which arteriography has been accomplished. Radiologic Findings The initial anteroposterior view of a one-year-old infant's abdomen reveals a huge mass displacing the stomach superiorly and the intestines toward the gutters (Fig. 1). A lateral view shows the mass arising in the retroperitoneum and displacing the stomach and intestines anteriorly (Fig. 2). No calcification is seen within the lesion. The regional bony skeleton is normal. A chest radiograph (not shown) was normal. An intravenous urogram (Fig. 3) delineates more clearly the boundaries of the mass which extends from the left hemi-diaphragm to the lower margin of the left sacroiliac joint and slightly to the right of the midline. The left kidney appears enlarged, but its borders are sharp. There is apparent pressure on the left pyelocalyceal system, with the infundibula appearing dilated, prominent, and slightly separated from each other. The right kidney is normal. There is partial obstruction of the proximal left ureter 3 cm below the ureteropelvic junction, due to compression by the mass. In view of these somewhat unusual findings and because the mass felt somewhat cystic to palpation, abdominal aortography was performed in an attempt to gain more useful information (Fig. 4). The aorta and superior mesenteric artery branches are displaced to the right by the large left retroperitoneal mass. The splenic artery and gastric vessels are displaced markedly superiorly. The right renal artery is normal, but there is elongation and stretching of the left renal artery and its intrarenal branches. Several left lumbar arteries likewise appear stretched. The mass is avascular except for several small vessels near the lower pole of the left kidney, which have a corkscrew appearance suggesting minimal neovascularity (Fig. 5). The nephrogram phase clearly outlines the enlarged left kidney within which are noted scattered multiple lucent defects (Fig. 6). The list of differential possibilities for a unilateral abdominal mass in an infant or child must include Wilms's tumor, neuroblastoma, and hydronephrotic or multicystic kidney as the probabilities on a statistical basis. Wilms's tumor may grow to the very large size shown by our mass and rapidly displace and compress the stomach, bowel, and adjacent organs.