Primary orbital melanoma associated with oculodermal melanocytosis

A 29-year-old, otherwise healthy man presented with an approximately 5-months' history of left-sided exophthalmos. The patient had a bluish-black pigmentation on his left upper lid, and black pigmentation on the left conjunctiva and sclera, since birth. CT examination revealed a retrobulbar tumor in the left orbit, and the left medial rectus muscle was wider than the right one. The left orbital cavity and the superior orbital fissure were enlarged. All of the examinations were negative in respect of another primary tumor outside the orbit or of tumor dissemination. At surgery, a pigmented tumor was found and removed. The orbital tissues were darkly pigmented. Histological examination of the excised tumor showed it to be an encapsulated, circumscribed mass. The tumor was built up of fusiform and spindle-shaped cells containing black pigmentation, with very few mitoses and without necrosis. There has been no recurrence or metastasis in 3 years of follow-up. The consequences of the tumorous transformation of oculodermal melanocytosis as reflected in the published literature and the special clinical and histopathological characteristics of our case are discussed.