Cerebral Mass Due to Neurocutaneous Melanosis: Eight Years Later

Abstract

Neurocutaneous melanosis (NCM) is associated most commonly with giant congenital melanocytic nevi (CMN), in particular those on the scalp or in a posterior axial location that are accompanied by satellite congenital nevi. It also can occur in patients with multiple medium-sized CMN. In general, the prognosis of those with symptomatic NCM is poor, even in the absence of malignancy, while the prognosis of those with asymptomatic NCM detected via screening varies and is more difficult to predict. Herein we report an asymptomatic patient with a giant CMN and multiple satellite nevi who had a screening magnetic resonance imaging (MRI) study at age 5 months that showed a rounded area of increased signal in the right temporal lobe on T1-weighted images, suggestive of parenchymal melanosis. This melanotic mass was resected at age 10 months, and histologic examination of the surgical specimen showed prominent perivascular collections of benign, pigment-containing melanocytes within cerebral tissue. The patient remains healthy 8 years later. His excellent long-term outcome and other reports of NCM with localized central nervous system (CNS) involvement apparent on MRI may have implications for management, including early imaging of patients with high-risk CMN and potential surgical intervention for NCM.

Fundus features of a case of neurocutaneous melanosis

“…4 Again, MRI may detect central nervous system melanosis in 26% of asymptomatic patients. 7 However, because the amount of melanin markedly diminishes during early months of life, MRI may not always be able to detect minimal quantities of melanin in older patients as in our case. 4 Our patient most likely belongs to a distinct subset of patients in whom a discrete intracranial mass becomes symptomatic at an older age (mean: 12.8 years) producing focal seizures, psychotic symptoms, and difficulties in speech.…”

“…4 Our patient most likely belongs to a distinct subset of patients in whom a discrete intracranial mass becomes symptomatic at an older age (mean: 12.8 years) producing focal seizures, psychotic symptoms, and difficulties in speech. 7 A wide variety of ocular findings have been reported in association with NCM. These include orbital melanoma, 6 eyelid ptosis and intermittent upward deviation of the eye, 9 choroidal nevus and limbal pseudoepitheliomatous hyperplasia, 8 papiledema, 10 disc hyperemia, and dilated veins.…”

Stable Neurocutaneous Melanosis in a Ten-Year-Old Boy with Controlled Partial-Complex Seizures

“…NCM may present as either symptomatic or asymptomatic based on clinical presentation. Typically the prognosis of patients with symptomatic NCM is poor, although the prognosis for asymptomatic NCM detected via screening is varied and unpredictable 15,14,16 . CNS symptoms of uncomplicated NCM include epilepsy and developmental delay, and these patients may reach adulthood.…”

Giant Melanocytic Nevus May Be Explained as a Superimposed Patchy Manifestation of a Polygenic Trait

“…Cases of GMN associated with small disseminated nevi involving the entire body have been documented with historical figures published in many articles and textbooks [4,5,6,7,8,9] and have also been reported in more recent publications [10,11,12,13]. So far, the associated small nevi have usually been categorized as ‘satellite lesions’ [4,12,13].…”

“…So far, the associated small nevi have usually been categorized as ‘satellite lesions’ [4,12,13]. Admittedly, true satellite lesions are often noted.…”