[Primary intramedullary melanoma. Apropos of a case].

Primary melanoma is a rare spinal tumour first reported by Hirschberg in 1906. Since then, only 34 cases have been reported. When present here a new case of primary intramedullary thoracic melanoma developed in a 64-year old male patient. MRI showed a paramagnetic signal with reactive cysts. Macroscopy and histology confirmed the diagnosis. Spinal cord melanoma is presumed to be primary when no other melanoma is found outside the CNS. The tumour is often located in the middle or lower thoracic cord, may be intra- or extra-medullary and leptomeningeal or extradural. It frequently progresses slowly. MRI is the essential examination as it demonstrates a lesion with paramagnetic properties. Its image is not specific and may correspond to other pigmented tumours (meningeal melanocytoma, melanotic schwannoma), to a lipoma or to a vascular or tumoral haemorrhagic lesion. Treatment is uncertain, but surgery is frequently associated with radiation. Postoperative follow-up aims at detecting a local regrowth of the tumour or leptomeningeal dissemination which affects the prognosis.