NRAS-mutated melanocytic BAP1-associated intradermal tumor (MBAIT): a case report

Virchows Arch. 2015 Jan;466(1):117-21. doi: 10.1007/s00428-014-1674-7. Epub 2014 Oct 24.

Abstract

Melanocytic BAP1-associated intradermal tumors (MBAITs) are epithelioid spitzoid looking, mostly intradermally located melanocytic tumors that often have tumor-infiltrating lymphocytes and a common nevus component. They occur sporadically but also in the context of an underlying BAP1 germline mutation. Recognition of these lesions is important because they can be a marker for an underlying BAP1-associated cancer syndrome. Most cases reported in the literature thus far were found to have both a BRAF and BAP1 mutation. Here, we report an unusual case of an MBAIT lesion with a combined NRAS and BAP1 mutation. A BAP1 germline mutation was excluded. Our case is the second case reported until now with this combination of mutations in this subset of lesions. In the other reported NRAS-/BAP1-mutated MBAIT case, presence of a BAP1 germline mutation was not tested. Our case confirms that the mutational spectrum in MBAITs is broader than previously thought. Just as in the BRAF-mutated cases, it is likely that a subset might be associated with a BAP1 germline mutation. In case of suspicion of an MBAIT lesion based on histological examination, diagnostic work-up should include assessment of protein expression and/or mutation analysis of at least BRAF, NRAS, and BAP1. Work-up should not be limited to analyzing only BRAF protein expression or mutation, since NRAS-mutated MBAITs might be missed.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Dermatologic Surgical Procedures
  • GTP Phosphohydrolases / genetics*
  • GTP Phosphohydrolases / metabolism
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Male
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism
  • Mutation / genetics*
  • Nevus, Intradermal / diagnosis
  • Nevus, Intradermal / genetics*
  • Nevus, Intradermal / surgery
  • Nevus, Pigmented / diagnosis
  • Nevus, Pigmented / genetics*
  • Nevus, Pigmented / surgery
  • Proto-Oncogene Proteins B-raf / genetics
  • Proto-Oncogene Proteins B-raf / metabolism
  • Skin / metabolism
  • Skin / pathology
  • Skin Neoplasms / diagnosis
  • Skin Neoplasms / genetics*
  • Skin Neoplasms / surgery
  • Tumor Suppressor Proteins / genetics*
  • Tumor Suppressor Proteins / metabolism
  • Ubiquitin Thiolesterase / genetics*
  • Ubiquitin Thiolesterase / metabolism

Substances

  • BAP1 protein, human
  • Biomarkers, Tumor
  • Membrane Proteins
  • Tumor Suppressor Proteins
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • Ubiquitin Thiolesterase
  • GTP Phosphohydrolases
  • NRAS protein, human