Malignant perivascular epithelioid cell tumor of the orbit: Report of a case and review of literature.

Perivascular epithelioid cell tumor (PEComa) is a rare neoplasm considered to arise from myomelanocytic cell lineage. The uterus is reportedly the most common site to be involved. Orbital PEComa is extremely rare with only two cases reported till date. A 5-year-old male presented with a right medial orbital mass for the last 6 months. The patient was diagnosed with alveolar soft part sarcoma elsewhere. Magnetic resonance imaging features were suggestive of lymphangioma with bleeding. The excision biopsy revealed multiple tumor cells comprising epithelioid cells with clear cytoplasm, along with nuclear atypia and mitosis. Immunohistochemistry was positive for HMB-45, smooth muscle actin, vimentin, and CD-34. It was negative for cytokeratin, S-100, and synaptophysin, which clinched the diagnosis of malignant orbital PEComa. Neoadjuvant chemotherapy was administered. There was no recurrence at 24 months of follow-up. At present, there is no consensus on management protocol for malignant PEComa. Complete surgical excision with chemotherapy appears to offer the best prognosis.