Neurocutaneous Melanosis

Rare skin (nevi) and meningeal pigmentation with a high risk of cutaneous or neural malignant degeneration.

Only a few cases have been described since 1987.

Sporadic.

Probably a developmental problem in the neural crest cells that ultimately form the skin and meninges.

At birth, large pigmented nevi, usually on the trunk, buttocks, or perineum. Cerebral MRI should be done before age 4 months to detect central nervous system (CNS) involvement.

Large pigmented nevi, usually on the trunk, buttocks, or perineum. CNS function may be normal at birth, but MRI examination is necessary to exclude brain or spinal cord involvement. If the CNS is involved, thickening and pigmentation of the meninges with focal accumulation of melanotic cells or brainstem lesions is observed. Progressive pigmentation and thickening of the meninges lead to cerebral deterioration, increased intracranial pressure, mental retardation, seizures, hydrocephalus, cranial nerve palsies, and spinal cord compression.

CNS involvement (especially presence of increased intracranial pressure, brainstem lesions) should be excluded by MRI and/or eye fundus examination. If neuraxial blockade is foreseen for postoperative pain management, spinal cord involvement should be excluded. In case of excision surgery, large blood loss should be foreseen.

In the presence of hydrocephalus, usual precautions to prevent any increase in intracranial pressure must be provided. If a spinal or epidural block is performed, the needle should not be inserted through a pigmented lesion to avoid skin coring and possible perimedullar implantation of melanocytes.

As for any neonatal anesthesia. Patients may require repeated general anesthesia or deep sedation for dressing changes. Patients with seizure activity should have medication optimized prior to surgery or receive intraoperative intravenous supplementation.

Giant Neonatal Nevus with No CNS Involvement: Sporadic; seems to be more frequent in Asian populations; early excision or laser therapy is performed by many medicosurgical teams for fear of malignant transformation.