Melanocytic tumors

2024-10-04   Scott Ryall, PhD 

1.Brigham and Women's Hospital, Harvard Medical School, Boston , MA (USA)

Classification

Definition

Primary meningeal melanocytic tumors are exceedingly rare, accounting for less than 1% of melanomas. 1 They arise from melanocytes located within the leptomeninges and can be histologically defined as circumscribed and benign or diffuse and malignant. They are then referred to as meningeal melanomatosis and meningeal melanocytosis, respectively. 2 While both adults and children may be affected by these lesions, they are more prevalent in children, particularly in the context of neurocutaneous melanosis (NMC). 3

Melanocytic CNS TumorsGenetic Event(s)
Meningeal melanocytosis/melanomatosisThe presence of activating mutations in BRAF, NRAS, and/or TERT are exceedingly rare in adults with primary melanocytic tumors in the CNS and likely indicate metastasis of a cutaneous melanoma. Rather, primary leptomeningeal melanocytic tumors in adults typically harbor variants in GNAQ or GNA11 mutations. 2,4-8 Additional molecular events involving SF3B1, EIF1AX, or BAP1 may indicate a more aggressive clinical course consistent with meningeal melanoma. 9 In contrast, children with primary leptomeningeal melanocytic tumors commonly have activating KRAS mutations, particularly in the context of neurocutaneous melanosis (NCM) OMIM: 249400, and infrequently, activating BRAF mutations. 10-14 DNA methylation analysis is useful for idenfying primary melanocytic tumors in the CNS and discriminating them from other metastatic melanoma. Further, it can aid in identifying those likely to behave more aggressively. 15

Article Bibliography

Reference NumberPubmed IDLast YearTitleAuthors
1117333172001MR findings of a primary intramedullary malignant melanoma: case report and literature review.Farrokh D et al
2255341282015Primary melanocytic tumors of the central nervous system: a review with focus on molecular aspects.Küsters-Vandevelde HV et al
3330482482020Neurocutaneous melanocytosis (melanosis).Ruggieri M et al
4208652672010Improved discrimination of melanotic schwannoma from melanocytic lesions by combined morphological and GNAQ mutational analysis.Küsters-Vandevelde HV et al
5214448622011Primary melanoma of the spinal cord: a case report, molecular footprint, and review of the literature.Fuld AD et al
6242747192013Is it a primary or metastatic melanocytic neoplasm of the central nervous system?: A molecular based approach.Cornejo KM et al
7253996932015Melanotic tumors of the nervous system are characterized by distinct mutational, chromosomal and epigenomic profiles.Koelsche C et al
8298917232018Integrated Genomic Classification of Melanocytic Tumors of the Central Nervous System Using Mutation Analysis, Copy Number Alterations, and DNA Methylation Profiling.Griewank KG et al
9270604462016Diagnosing a Primary Leptomeningeal Melanoma by Gene Mutation Signature.van de Nes J et al
10233039022013Primary melanoma of the CNS in children is driven by congenital expression of oncogenic NRAS in melanocytes.Pedersen M et al
11233922942013Multiple congenital melanocytic nevi and neurocutaneous melanosis are caused by postzygotic mutations in codon 61 of NRAS.Kinsler VA et al
12254875652015Case reports of fatal or metastasizing melanoma in children and adolescents: a systematic analysis of the literature.Neuhold JC et al
13254907152015BRAF mutations are also associated with neurocutaneous melanocytosis and large/giant congenital melanocytic nevi.Salgado CM et al
14282535232017MEK inhibition appears to improve symptom control in primary NRAS-driven CNS melanoma in children.Kinsler VA et al
15295396392018DNA methylation-based classification of central nervous system tumours.Capper D et al

Citation

Scott Ryall, PhD

Melanocytic tumors

Atlas Genet Cytogenet Oncol Haematol. 2024-10-04

Online version: http://atlasgeneticsoncology.org/solid-tumor/209267/melanocytic-tumors