Neurocutaneous melanosis, or neurocutaneous melanomatosis, is a rare sporadic phakomatosis.
Pathology and clinical features
The disease is characterised by melanoytic naevi in skin and brain (40-60%). Melanoblasts from neural crest cells are present in the leptomeninges, eye globes, inner ear, sinonasal cavity and skin
Usually the disease is discovered in childhood due to intracranial haemorrhage, or hydrocephalous from blocked arachnoid villi.
Giant cutaneous naevi are present. Malignant transformation of cutaneous naevi is uncommon. Malignant transformation of CNS melanosis occurs in up to 50%.
Prognosis in symptomatic cases is extremely poor, even in the absence of malignant transformations.
Features for diagnosis have been proposed 2:
- unduly large or unusually numerous pigmented nevi in association with leptomeningeal melanosis or melanoma
- no evidence of malignant change in any of the cutaneous lesions
- no evidence of malignant melanoma in any organ apart from the meninges
- hyperdensity (due to melanin) outlining sulci
- melanin may be seen on unenhanced T1W MRI as hyperintensity
- diffuse enhancement of meninges in brain and spine (20%)
Hyperdense outline of sulci on CT can mimic subarachnoid haemorrhage.
- neurofibromatosis type 1 (NF1) (von Recklinghausen disease)
- neurofibromatosis type 2 (NF2) (mnemonic)
- tuberous sclerosis (Bourneville-Pringle disease)
- ataxia telangiectasia
- Sturge-Weber syndrome (encephalotrigeminal angiomatosis)
- von Hippel-Lindau disease (retinocerebellar angiomatosis)
- incontinentia pigmenti (Bloch-Sulzberger syndrome)
- basal cell naevus syndrome (Gorlin-Goltz syndrome)
- Wyburn-Mason syndrome (Bonnet-Dechaume-Blanc syndrome)
- encephalocraniocutaneous lipomatosis
- hypomelanosis of Ito
- Nijmegen breakage syndrome
- epidermal naevus syndrome
- neurocutaneous melanosis
- progressive facial hemiatrophy (Parry-Romberg syndrome)
- PHACE syndrome
- Cowden disease/COLD syndrome
- Gomez-Lopez-Hernandez syndrome
- 1. Di Rocco F, Sabatino G, Koutzoglou M et-al. Neurocutaneous melanosis. Childs Nerv Syst. 2004;20 (1): 23-8. doi:10.1007/s00381-003-0835-9 - Pubmed citation
- 2. Fox H. Neurocutaneous melanosis. In: Vinken PJ, Bruyn GW, eds. Handbook of Clinical Neurology. Amsterdam: North Holland;1972 :14:414–428
- 3. Chu WC, Lee V, Chan YL et-al. Neurocutaneous melanomatosis with a rapidly deteriorating course. AJNR Am J Neuroradiol. 2003;24 (2): 287-90. Pubmed citation