CYSTIC PARAGANGLIOMA OF THE RENAL CAPSULE

Abstract

A 42-year-old black woman from Ghana was referred for evaluation of recurrent pain in the left flank. Physical examination revealed a voluminous palpable mass in the left upper abdomen. Laboratory values, including catecholamine levels (urinary vanillylmandelic acid excretion per 24 hours), were normal except for peripheral eosinophilia. The patient had no hypertension. Computerized tomography showed an 11 cm. left cystic renal mass of the lower pole (fig. 1). Intravenous contrast injection revealed that the mass had thickened irregular septa running through it. Imaging studies did not afford an unequivocal interpretation. However, peripheral eosinophilia and the fact that the patient was of African origin led us to suspect a renal hydatid cyst. Intraoperatively the tumor was well demarcated from the renal parenchyma and surrounding organs and enclosed by the renal capsule. Therefore, it was extirpated, leaving the renal parenchyma intact. Grossly the tumor was well circumscribed and multilocular, and contained abundant hemorrhagic fluid. Histologically, the tumor was composed of small monomorphic spindle cells and was strongly immunoreactive for chromogranin, vimentin and neuron specific enolase but not for cytokeratins (fig. 2). Pathological features were consistent with a cystic extra-adrenal paraganglioma. Scintigraphic imaging with 131 iodine-metaiodobenzylguanidine for evaluation of metastatic disease was negative. No additional treatment was given. The patient was well at 10-month followup. DISCUSSION