MULTILOCULAR CYSTIC RENAL NEOPLASM OF LOW MALIGNANT POTENTIAL WITH CHRONIC PYELONEPHRITIS: A RARE ENTITY

Multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) is a neoplasm grouped under clear cell renal tumors. Its incidence ranges from 0.5 to 2.5 % of all renal tumors. This study brings out a rare case report and highlights the importance of differentiating it from its mimics. A 57 years old female presented with right flank pain for 6 months. CT KUB showed Bosniak type III renal cyst. Right radical nephrectomy was performed. Macroscopically, a well circumscribed exophytic mass was seen on the posterior surface of lower pole of right kidney measuring 6 × 5.3 × 4.2 cm. Its cut surface showed multiple cysts containing clear to gelatinous material separated by thin septations. The pelvicalyceal system was dilated. Microscopically, a well encapsulated multilocular cystic neoplasm was seen having numerous fibrous septa composed of clear cells with round uniform nuclei and inconspicuous nucleoli (ISUP grade 1). Cyst lumen had eosinophilic secretions. No necrosis, vascular or fat invasion was noted. Features of chronic pyelonephritis were seen. A diagnosis of Multilocular cystic renal neoplasm of low malignant potential with chronic pyelonephritis was made. AJCC TNM staging – pT1b MCRNLMP has an excellent prognosis, irrespective of the tumor stage. Nephron sparing surgery is curative