Meningeal melanomas associated with transforming Ota nevus to malignant melanoma: a case report

Intracranial invasion of cellular blue nevus (CBN) from the skin is extremely rare and such a condition with malignant transformation is even rarer. A case of meningeal melanoma with malignant transformation which was derived from an Ota nevus is presented in this report. A21-year-old man with a neurocutaneous syndrome since childhood was referred with headache and mild left hemiparesia. CT scan and MRI demonstrated intracranial lesions and conjunctival biopsy leads to the pathologic diagnosis of blue nevus. Thereafter his parietal lesion was operated by craniotomy with total gross excision. On histopathological examination, diagnosis of malignant melanoma was confirmed. Approximately 2 months after radiotherapy and chemotherapy, he afflicted to diplopia and blurred vision on the leftside due to enlargement of orbital and cavernous sinus lesion. Following one year follow-up, he was survived and thrived with diffuse leptomeningeal nodular enhancement in favor of melanoma dissemination. Primary intracranial melanomas are though rare, but it should be suspected especially in the presence of periorbital blue nevus or nevus of Ota. Moreover, although CBN is considered benign, scalp or periorbital CBN has the potential for intracranial invasion and malignant transformation.