Perivascular epithelioid tumor of urinary bladder and vagina.

Perivascular epithelioid cell tumors are recently characterized neoplasms composed of large clear HMB-45-positive epithelioid cells arranged in an organoid pattern. The histogenesis of these neoplasms remain obscure. We report here 2 such tumors in young female patients aged 19 and 16 years involving the urinary bladder and vagina, respectively (in the absence of the tuberous sclerosis complex) . Microscopically, both tumors were composed of perivascularly arranged cells with granular eosinophilic fluffy cytoplasm, round-to-oval nuclei, and prominent nucleoli. Melanin pigmentation was present in the vaginal tumor. Immunohistochemically, both tumors strongly expressed HMB-45. They were negative for cytokeratin, vimentin, and S-100. The vaginal tumor recurred 10 months after resection and chemotherapy. The patient with the bladder tumor was lost to follow-up.