Congenital neurocutaneous melanosis with metastatic orbital malignant melanoma.

Proptosis and ptosis, caused by a large orbital mass that was excised and determined to be malignant melanoma, developed in a 4-year-old girl with congenital neurocutaneous melanosis (multiple large or giant cutaneous nevi associated with abnormal leptomeningeal pigmentation). Shortly thereafter, the patient had evidence suggestive of systemic metastases and died. The orbital tumor was likely metastatic from a primary meningeal melanoma. Other possible sources of metastatic tumor are discussed. It is unlikely that this was a primary orbital melanoma because the patient had no clinical or pathologic manifestations of pre-existing oculocutaneous melanosis, orbital melanosis, or orbital blue nevus.