Is it a primary or metastatic melanocytic neoplasm of the central nervous system?: A molecular based approach

Pathol Int. 2013 Nov;63(11):559-64. doi: 10.1111/pin.12107.


Primary melanocytic neoplasms of the central nervous system (CNS) are uncommon and must be distinguished from metastatic lesions as patients with metastatic disease carry a worse prognosis. Therefore, tools to aid in the diagnosis of a primary CNS melanocytic neoplasm would be of clinical utility. Primary CNS melanocytic neoplasms, including uveal melanomas have frequent mutations in GNAQ and GNA11, but are rare in cutaneous and mucosal melanomas. Additionally, primary uveal melanomas often exhibit monosomy 3 conferring an elevated risk of metastasis. We present a 63 year-old male with a melanocytic neoplasm in the thoracic spinal cord. Molecular studies revealed the tumor contained a GNAQ mutation and four-color fluorescent in situ hybridization (FISH) composed of chromosome enumeration probes for 3, 7, 17 and a locus specific probe for 9p21/CDKN2A yielded a normal result (i.e. two copies per cell), favoring a primary versus metastatic melanocytic neoplasm of the CNS. We report a case in which the combination of mutational analysis and FISH aided in identifying the origin of the neoplasm.

Keywords: GNA11 mutation; GNAQ mutation; melanocytoma; metastatic melanoma; primary CNS melanocytic neoplasm; urovysion.

Publication types

  • Case Reports

MeSH terms

  • Central Nervous System Neoplasms / genetics
  • Central Nervous System Neoplasms / pathology*
  • Central Nervous System Neoplasms / secondary
  • DNA Mutational Analysis
  • Diagnosis, Differential
  • Humans
  • Male
  • Melanocytes / pathology*
  • Melanoma / genetics
  • Melanoma / pathology*
  • Melanoma / secondary
  • Middle Aged