• We report a case of primary orbital melanoma in a 17-year-old girl. The patient presented with painless proptosis during the first trimester of pregnancy. Computed tomography demonstrated a well-circumscribed mass located infratemporally in the right orbit. The tumor was bluish-black, grossly encapsulated, and associated with orbital blue nevi. Histologic examination of the mass revealed a pigmented spindle-cell neoplasm. On electron microscopy, the presence of premelanosomes and the absence of basal lamina supported the diagnosis of melanoma. Malignant transformation of a preexisting nevus is postulated since perineural foci of benign dendritic melanocytes were seen within the melanoma. There has been no recurrence or metastasis in a 2-year follow-up. Of 30 primary orbital melanomas reviewed, 12 (40%) were associated with periorbital pigmentary disorders, such as oculodermal melanocytosis, blue nevus, and ocular melanocytosis. Our case is unique since the pigmentary lesions were limited to the orbital tissues.
Rice CD, Brown HH. Primary Orbital Melanoma Associated With Orbital Melanocytosis. Arch Ophthalmol. 1990;108(8):1130-1134. doi:10.1001/archopht.1990.01070100086040