NEUROCUTANEOUS MELANOSIS AND DANDY-WALKER SYNDROME IN AN INFANT

An 18-week-old boy was referred by the pediatric service for evaluatio n of a large congenital nevus. The baby was a term infant who was note d to have extensive pigmented skin lesions at birth that extended from the scalp to the feet. Apgar scores and physical examination (includi ng neuromuscular examination) were within normal limits. Electroenceph alographic tracings were normal and unenhanced cranial computerized to mography (CT) was reported as showing a subarachnoid cyst with atrophi c changes, involving predominantly the inferior aspect of the cerebell ar hemispheres bilaterally. Hydrocephalus or signs thereof were not pr esent. Lumbar spine films were normal. The patient was next evaluated at age 3 months, where he was reported to roll over, reach for objects , and smile. At age 17 weeks, the baby had dermabrasion of an abdomina l portion of his congenital nevus, followed by autologous epidermal ce ll autograft. The baby was subsequently hospitalized at the University of California Irvine Medical Center for complications from this proce dure. Upon initial dermatologic evaluation, the baby was noted to have uniformly brown pigmented bathing-trunk verrucous lesions covering hi s buttocks, scrotum, two-thirds of his trunk, and proximal portions of his extremities. Multiple similar but smaller lesions were noted on t he lace, scalp, and distal extremities (Fig. 1). Tense anterior fontan elles, frontal bossing, Babinski reflexes bilaterally and possible ''s etting-sun'' sign (downward gaze of the eyes secondary to pressure fro m the midbrain) were apparent. Although the length (size) percentile f or the baby was normal, the plot of head circumference was noted to de viate above the normal range by age 3 months. Magnetic resonance imagi ng (MRI) of the brain was performed. The midline sagittal T1 weighted image (Fig. 2a) demonstrated an enlarged posterior fossa with Vermin h ypoplasia and hydrocephalus. An axial image through the dilated sylvia n aqueduct revealed a hyperintense focus, characteristic of melanocyte s, adjacent to the dilated left temporal horn (Fig, 2b). More superior ly, enhancing leptomeningeal deposits were identified (not shown). Cer ebrospinal fluid was obtained after subsequent placement of a right ve ntricular-peritoneal shunt. The fluid was bloody, hut sterile, and wit hout malignant cells. Staining for melanin of the few nucleated cells in this limited cerebrospinal fluid sample was negative. Several excis ional biopsies of a nevus from locations on the feet, wrist, back, and buttock showed the picture of either congenital melanocytic nevus or congenital melanocytic nevus with atypical melanocytio hyperplasia; ho wever, no significant atypia was identified in the specimens containin g foci of atypical melanocytic hyperplasia.