An orbital perivascular epithelioid cell tumor in a 7-year-old boy: case report and review of the literature.

We report the case of a 7-year-old boy who presented with a swollen right eye. Magnetic resonance imaging revealed a right intraconal orbital mass with intense contrast enhancement. Incisional biopsy led to a diagnosis of perivascular epithelioid cell tumor (PEComa). Sirolimus was initiated but discontinued at the third week of treatment because the tumor had progressed. A minor regression of the tumor was seen after six cycles of systemic chemotherapy. Previously reported cases of PEComa were benign in nature, and full remission was achieved with surgical excision. In the present case the tumor was malignant and responded only slightly to systemic chemotherapy.