Renal epithelioid angiomyolipoma: a case report and literature review.

Background: Renal epithelioid angiomyolipoma is a recently recognized variant of angiomyolipoma, closely simulating renal cell carcinoma both clinically and histologically. Only a relatively small number of cases of epithelioid angiomyolipoma of the kidney have been reported.
Aim: To highlight clinicopathological features of this rare tumour.
Observation: We report herein a new case of renal epithelioid angiomyolipoma in a 38-year-old male with no stigmata of tuberous sclerosis. The tumour was composed of diffuse sheets of epithelioid cells, small numbers of adipocytes and occasional blood vessels. Immunohistochemically, neoplastic cells were immunoreactive for HMB-45, but negative for cytokeratin. The patient showed no evidence of recurrence or metastatic disease one year after radical nephrectomy.
Conclusions: Epithelioid angiomyolipoma may be locally aggressive and can metastasise; therefore, long-term post-operative follow-up is mandatory.