The disease is characterised by melanotic naevi in skin. The diagnosis is often made in the first few years of life when the child presents with hydrocephalus due to meningeal melanocytosis/meningeal melanomatosis (aka diffuse melanosis) 5.
Diagnostic features 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
It is believed that neurocutaneous melanosis is the result of congenital dysplasia of melanoblasts (melanocyte precursors) which are of neural crest cells origin. These are located in the leptomeninges, globes, inner ear, sinonasal cavity and skin 1,4.
For leptomeningeal imaging features, please refer to meningeal melanocytosis.
In addition to or instead of leptomeningeal involvement, parenchymal changes are seen in some individuals characterised by T1 signal hyperintensity involving the mesial temporal lobes (particularly the amygdala), ventral pons and medulla 6.
Dandy-Walker malformation is also not infrequently identified 6,7.
Treatment and prognosis
Prognosis in symptomatic cases is extremely poor, even in the absence of malignant transformations.
Malignant transformation of cutaneous naevi is variably reported from 2-13% 4.
Malignant transformation of CNS melanosis occurs very frequently, in up to 50% 5.
- 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
- 4. Painter TJ, Chaljub G, Sethi R, Singh H, Gelman B. Intracranial and intraspinal meningeal melanocytosis. AJNR. American journal of neuroradiology. 21 (7): 1349-53. Pubmed
- 5. Seth Love, David Louis, David W Ellison. Greenfield's Neuropathology, 2-Volume Set, Eighth Edition. ISBN: 9780340906811
- 6. Gocmen R, Guler E, Arslan EA. A case of neurocutaneous melanosis and neuroimaging findings. Journal of radiology case reports. 9 (3): 1-6. doi:10.3941/jrcr.v9i3.2141 - Pubmed
- 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