Neurocutaneous melanosis with associated Dandy-Walker complex.

CASE REPORT: The authors report the case of a child with neurocutaneous melanosis associated with a Dandy-Walker complex. Magnetic resonance (MR) images showed shortened T1-weighted images in areas involving the amygdala, mesencephalon, rostral brain stem, and superior cerebellar surface compatible with melanin deposits. There was also partial agenesis of the cerebellar vermis with an enlarged fourth ventricle cyst along with a high-lying torcular and ventricular enlargement. Endoscopic fenestration and biopsy of the cyst wall was performed without evidence of abnormal melanin deposits in the meninges. OUTCOME: The patient eventually required ventriculoperitoneal shunting and at 1-year follow-up did not develop evidence of primary CNS melanoma. ILLUSTRATION: Computed tomography and MR images consistent with neurocutaneous melanosis and the Dandy-Walker complex are presented along with photographs of the cutaneous nevi. DISCUSSION: The major clinical and radiological features of this rare association, with only 11 previously reported cases, are discussed in detail.