Orbital Pigmented Epithelioid Melanocytoma Tumor Associated With Nevus of Ota (Oculodermal Melanocytosis)

The authors report a patient with nevus of Ota (oculodermal melanocytosis) who presented with pigmented epithelioid melanocytoma in the right orbit. A 36-year-old female patient attended with proptosis OD and diplopia for 3 months. MRI disclosed an expansive lesion adhered to the right inferior rectus muscle, enlargement of the superior orbital fissure, and filling of the right cavernous sinus. Excision of the orbital mass through a transconjunctival inferior fornix access disclosed a heavily pigmented lesion. Anatomopathological study revealed a diagnosis of pigmented epithelioid melanocytoma. A positron emission tomography scan did not show any metastasis. The patient was submitted to radiotherapy, had an improvement of the proptosis and diplopia, and showed no distant metastases for 3 years now. Pigmented epithelioid melanocytoma belongs to the group of heavily pigmented neoplasms, as do atypical blue nevus, which is characterized by prominent melanin production and a low degree of malignancy.