Trigeminal Metastasis of Malignant Melanoma: Clinical, Neuroradiological, and Pathological Features. A Case Report.

Background: Perineural spread of malignant melanoma (MM) along cranial nerves is a rare complication of MM of the head and neck.

Methods: A 78-year-old man presented with untreatable facial pain and cutaneous hypoesthesia in V2/V3 branches of right trigeminal nerve. Six months earlier patient removed a lentigo maligna melanoma in his right upper lip and a MM in his right gingiva. Brain magnetic resonance imaging showed pathologic thickening of the right maxillary and mandibular nerves and of the intracranial trigeminal nerve. Infraorbital nerve biopsy confirms MM neural metastasis. BRAFV600E mutation was identified only in the lentigo maligna melanoma. Patient was treated with brain proton therapy but 5 months later developed sensorimotor deficit of his right arm because of a cervical metastasis.

Conclusions: In patients presenting with atypical facial pain and history of head and neck melanoma a trigeminal spreading should be considered. Magnetic resonance imaging can detect early perineural spread and target biopsy.