February 2023 – Presented by Dr. Ahresh Saha (Mentored by Dr. Frank Melgoza)

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Clinical History

A 65 year old male presented to DGMC with epigastric abdominal pain. CT scan showed a 5 cm left renal mass in the midpole that appears well circumscribed and is ~70% exophytic. It touches the collecting system. On the inferior aspect, it is adjacent to a large simple cyst. The rest of the left kidney and right kidney is normal (with a few small simple cysts). No LAD. No metastasis. A left partial nephrectomy was performed.

Gross examination of the tumor confirmed a single mass arising in the midpole of the left kidney. Histological slides revealed these findings:

Microscopy

This interesting finding was seen arising adjacent to the tumor: