Primary leptomeningeal melanoma in a child.

Primary malignant melanoma of the leptomeninges is a rare and aggressive tumor in children and accounts for less than 1% of all pediatric malignancies. Usually its symptoms include raised intracraneal pressure resulting from hydrocephalus secondary to tumoral obliteration of basal cisterns, but the passage of time from the initial symptomatology to diagnosis is frequently delayed. A 7-year-old male with primary leptomeningeal melanoma is reported. At the beginning, he presented ataxia and dysarthria followed by symptoms of raised intracranial pressure, complex partial seizures, progressive loss of consciousness, and coma. Cerebrospinal fluid analysis demonstrated raised opening pressure, normal glucose, and increased protein concentration, but malignant melanoma cells were not found. Magnetic resonance imaging scans depicted bright signals in the subarachnoid spaces on T(1) images and gadolinium-enhanced focal lesions. Cerebral biopsy was proposed, but it was not authorized. Definitive diagnosis was thus made by pathologic postmortem examination.