Spectrum of Clinical, Neuroimaging, and Cerebrospinal Fluid Features of Adult Neurocutaneous Melanocytosis.

BACKGROUND: Neurocutaneous melanocytosis (NCM) is a poorly understood disease due to its rarity. This study aimed to summarize the characteristics of adult NCM and improve the awareness of this disease. METHODS: The clinical data of 13 adult patients with NCM were retrospectively reviewed, including neuroimages, cerebrospinal fluid (CSF), and histological features. RESULTS: There were 9 males and 4 females. The mean age at symptom onset was 36.5 years. The initial symptoms included intracranial hypertension in 8 patients and seizure in 4 patients. Ten patients had large and/or multiple congenital melanocytic nevi. MRI revealed hydrocephalus and diffuse thickening of the leptomeninges with T1 shortening in all patients. Post-contrast T1-weighted images showed diffuse linear enhancement of the leptomeninges. Lumbar punctures showed increased open pressure, and elevated protein levels and decreased glucose concentrations in CSF. Cells with intracytoplasmic coarse black granules were found in the CSF and were positive for S100, HMB45, and vimentin. Histopathology of the cutaneous lesions and meninges showed melanocytes but no evidence of malignant melanoma. CONCLUSION: Adult NCM patients present a diversity of clinical manifestations. Brain MRI showing diffuse thickening of the leptomeninges with T1 shortening is useful in diagnosing NCM. Heterocellular melanin may be of great value for early diagnosis of NCM in challenging cases.

Melanosis neurocutánea / Neurocutaneous melanosis

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Neurocutaneous melanosis.

Neurocutaneous melanosis (NCM) is a rare phakomatosis characterized by a focal or diffuse proliferation of melanin-producing cells in both the skin and the leptomeninges. This syndrome is believed to result from an error in the morphogenesis of embryonal neuroectoderm. Two-thirds of patients with NCM have giant congenital melanocytic nevi, and the remaining one-third have numerous lesions but no giant lesions. Patients may present with neurologic manifestations early in life secondary to intracranial hemorrhages, impairment of cerebrospinal fluid circulation, or malignant transformation of the melanocytes. The prognosis of patients with symptomatic NCM is poor.

Diffuse leptomeningeal hyperintensity on fluid-attenuated inversion recovery MR images in neurocutaneous melanosis.

Neurocutaneous melanosis (NCM) is a rare neuroectodermal dysplasia characterized by large or multiple cutaneous congenital pigmented nevi and benign or malignant melanocytic tumors of the leptomeninges. Although the MR manifestations of this disease have been reported in a small series of cases, the usefulness of fluid-attenuated inversion recovery (FLAIR) MR findings has not been documented. We present a case of NCM that showed diffuse leptomeningeal hyperintensity on FLAIR images. This FLAIR finding may be a clue to the detection of leptomeningeal abnormalities in NCM.

[Melanocytic meningitis and large congenital melanocytic naevus: neurocutaneous melanosis]. / Méningite mélanocytaire et naevus géant congénital: la mélanose neurocutanée.

Neurological symptoms in a patient with large congenital melanocytic naevus are highly suggestive of cerebromeningeal melanoma metastasis. The presence of melanocytic cells in cerebrospinal fluid confirms this diagnosis If their malignant nature is shared with cutaneous naevocytic cells. Conversely, neurocutaneous melanosis is diagnosed when benign melanocytosis meningitis is found in patients with multiple and/or large congenital melanocytic naevus, whether cutaneous naevus cells are benign or not, or when cerebrospinal fluid cells are malignant with benign cutaneous melanocytic naevus. We report the case of a young man aged 19 presenting with multiple and large congenital melanocytic naevus who experienced transcient neurological signs and increased intracranial pressure. Cerebral neuroimaging evoked meningeal infiltration which benign melanocytic nature was supposed on CSF analysis and confirmed by necropsy findings, only 3 month after neurological onset, leading to neurocutaneous melanosis diagnosis. This rare neuroectodermal dysembryoplasia finds expression in various neurological signs, depending on patient's age and leptomeningeal and/or cerebral proliferation localization. Lumbar puncture, cerebral scanography and MRI may help diagnosis, but only histological examination can prove neurocutaneous melanosis, more often by necropsy because of poor prognosis.

Peritoneal implantation of meningeal melanosis via ventriculoperitoneal shunt: a case report and review of the literature.

Systemic spread of primary intracranial neoplasms is rare and may be due to ventriculoperitoneal shunt (VPS). The most common tumors to metastasize via VPS are germinoma of the pineal gland and medulloblastoma. We report a case of 16-yr-old girl with central nervous system malignant melanosis who developed subsequent peritoneal implants via VPS. To the best of our knowledge, this patient represents the third reported case of meningeal melanosis or melanoma which metastasized to the peritoneal cavity via VPS. The VPS should be considered as possible mode of systemic spread in patients with primary cranial malignancy.

MR of leptomeningeal melanosis in children.

PURPOSE: To delineate the magnetic resonance (MR) appearance of leptomeningeal melanosis in children. METHOD: Retrospective review of the medical, surgical, pathologic and MR findings in four children with a confirmed histologic diagnosis of leptomeningeal melanosis. The brain MR was performed with T1- and T2-weighted images in all four children and three had T1-weighted post-gadolinium images. Two of the children also had T1-weighted post gadolinium spine images. RESULTS: The MR brain findings consisted of cortical plaque and nodular hyperintense lesions on the noncontrast T1-weighted images in one child, marked, diffuse leptomeningeal enhancement in two children, and an enlarged, hypointense left temporal lobe with adjacent mild leptomeningeal enhancement in one child. The MR spine findings consisted of diffuse leptomeningeal enhancement in one child and hyperintensity of the cerebrospinal fluid in the other. CONCLUSION: The T1-weighted pre- and post-contrast images were the best to demonstrate the MR findings in leptomeningeal melanosis which consisted of either diffuse or localized enhancement of the leptomeninges; or cortical plaque and nodular hyperintense lesions pre-contrast.

[Neurocutaneous melanosis. Report of a case]. / Melanose neuro-cutânea. Relato de um caso.

The clinical, laboratorial and radiological features of a 3-month-old child with neurocutaneous melanosis are described. The patient was born with multiple disseminated benign cutaneous nevi, proven by skin-biopsy, and presented with drug-resistant seizures and psycho-motor retardation. Serial cerebrospinal fluid studies showed high protein and low glucose levels, with pleocytosis and malignant cells in the fluid. Pneumoencephalogram showed mild non-obstructive hydrocephalus. Immunological studies showed normal immunological activity at three months of age and very poor activity at one year. The patient died at 16 months of age, after the sudden onset of intracranial hypertension and meningeal signs. Immunotherapy and chemotherapy were suggested but not accepted by the family. Some comments are made based on this and other 43 cases described in the literature; the value of laboratory studies in detecting malignant transformaiton in the meninges in patients with benign skin nevi is stressed.