Intracranial trigeminal nerve metastasis of a desmoplastic neurotropic melanoma: case report.

Background: Desmoplastic neurotropic mela-noma is a rare and highly malignant variant of melanoma. Solitary nervus trigeminus and Gasserian ganglion metastasis of a neurotropic melanoma has not been previously described in the literature.

Methods: A 69-year-old man presented to our clinic with trigeminal neuralgia. 4 years previously he underwent tumor removal with an initial diagnosis of amelanotic malignant cutaneous melanoma; 1 year later, because of tumor recurrence, the patient underwent neck dissection, chemotherapy and radiation. Magnet resonance imaging (MRI) disclosed an enhancement of the Gasserian ganglion and tumor extension along the mandibular and maxillar nerves of the intracranial part of the trigeminal nerve suggestive of tumor. The intraoperative macroscopic appearance of the tumor was compatible with a neurinoma. Histopathological studies proved the tumor to be a desmoplastic neurotropic melanoma (DNM) that was related to the previously treated malignant melanoma.

Conclusions: A metastatic tumor arising solely in a trigeminal nerve from a cutaneous malignant melanoma is quite rare; to our knowledge this may be the first report of such a case in the literature.