Micropapillary pattern in a case of multilocular cystic renal neoplasm of low malignant potential

Abstract

Multilocular cystic renal neoplasm of low malignant potential, formerly known as multilocular cystic renal cell carcinoma, is a relatively uncommon renal neoplasm. The peculiarity of this neoplasm lies in the absence of expansile solid nodules. We report a case of this uncommon neoplasm with a focal micropapillary pattern, which is a very rare feature. To the best of our knowledge, there are no case reports emphasizing on the micropapillary pattern in case of multilocular cystic renal neoplasm of low malignant potential. We report a case of a 57-year-old female patient who presented with pain abdomen. Ultrasound and computerized tomography of abdomen revealed a multilocular cystic renal mass. The patient underwent right nephrectomy and the specimen was sent for histopathological examination. Grossly, the enlarged lower pole on cutting open showed multiloculated fluid-filled cyst with smooth inner walls. Microscopically, the tumor was composed of cysts lined by cells with clear cytoplasm and of Fuhrman nuclear Grade 1. A rare feature seen was the disposition of tumor cells in micropapillary pattern. The case was reported as multilocular cystic renal neoplasm of low malignant potential. This neoplasm needs special consideration due to its good prognosis and potential amenability to cure by nephron-sparing surgery. Also to be noted is that a multilocular cystic renal neoplasm of low malignant potential can have a micropapillary pattern too.