Partial nephrectomy in multiple mixed epithelial and stromal tumors (MEST)

Mixed epithelial and stromal tumor (MEST) of the kidney is not a common diagnosis. This tumor usually mimics solid-cystic malignant renal tumors and most cases are treated surgically. Here, we presented a 35-year-old female with simultaneous two separate large solid-cystic masses with contrast enhancement in lower and upper pole of left kidney which were managed surgically via partial nephrectomy. Microscopic evaluation showed solid-cystic tumor with variably sized cysts lined by flattened to cuboidal epithelium that was compatible with MEST. Follow up evaluation revealed normal parenchymal renal tissue and proper function without any evidence of local recurrence.