Background:
Cerebellopontine angle represents a complex anatomical area of the brain. A cerebellopontine angle lesion could be a vestibular schwannoma, meningioma, epidermoid cyst, or less likely, arachnoid cyst, metastasis, lower cranial nerves schwannoma, lipoma, hemangioma, paraganglioma, or vertebra-basilar dolichoectasia. Primary meningeal melanocytoma is a rare neoplasm, especially when it occurs at the cerebellopontine angle. Nevus of Ota (aka oculodermal melanocytosis) is a hyperpigmentation along the distribution of the ophthalmic and maxillary branches of trigeminal nerve; it occurs due to entrapment of melanocytes at the upper third of the dermis. It may not present at birth and may show up at puberty.
Case description:
We describe a case of primary meningeal melanocytoma of the cerebellopontine angle associated with nevus of Ota in a 46-year-old male patient presented with 7-day history of left arm weakness and vertigo. Computed tomography and MRI showed right-sided cerebellopontine angle mass, which was resected. Histopathology confirmed the meningeal melanocytic lesion and revealed its nature.
Conclusion:
Primary meningeal melanocytoma of the brain is a rare but benign tumor; the association between meningeal melanocytoma and nevus of Ota is also rare and possibly explained by their common embryonic origin from neural crest cells. There are six cases reported so far in literature including our case for meningeal melanocytoma associated with nevus of Ota.