This patient went on to have a partial nephrectomy.
DESCRIPTION: "Partial nephrectomy": The specimen consists of a segment
of kidney weighing 23g and measuring 42x52x30mm. Resection margins are
inked. Serial sectioning reveals a well circumscribed, nodular, partly
tan, yellow tumour 30x23x25mm. Tumour abuts the inked resection
margins. Within the tumour there are focal areas of haemorrhage. There
is no invasion beyond the renal capsule.
The sections of kidney show a circumscribed moderately hypercellular
tumour enclosed within a fibrous capsule of varying thickness. Tumour
cells have round oval and angulated hyperchromatic nuclei and a variable
amount of cytoplasm which contains dense eosinophilc, PTAH positive
granules. No mitotic figures or areas of necrosis are identified and no
capsular or vascular invasion is seen. The adjacent renal parenchyma
is unremarkable. Immunohistochemistry shows patchy staining for CK7 in
tumour cells. Occasional CD10 positive cells are also noted.
FINAL DIAGNOSIS: Oncocytoma