title: NRAS-mutated melanocytic BAP1-associated intradermal tumor (MBAIT): a case report.
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.
authors.affiliation: Department of Pathology, Radboud University Medical Center, P.O. Box 9101, Nijmegen, The Netherlands, willeke.blokx@radboudumc.nl.
authors.forename: Willeke A M
authors.initials: WA
authors.lastname: Blokx
authors.forename: Katrin
authors.initials: K
authors.lastname: Rabold
authors.forename: H Jorn
authors.initials: HJ
authors.lastname: Bovenschen
authors.forename: Marjolijn J L
authors.initials: MJ
authors.lastname: Ligtenberg
authors.forename: Arjen R
authors.initials: AR
authors.lastname: Mensenkamp
authors.forename: Gesina
authors.initials: G
authors.lastname: van Lijnschoten
authors.forename: Wendy A G
authors.initials: WA
authors.lastname: van Zelst-Stams
authors.forename: Patricia J T A
authors.initials: PJ
authors.lastname: Groenen
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D062109:Dermatologic Surgical Procedures; D020558:GTP Phosphohydrolases / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D018330:Nevus, Intradermal / Q000175:diagnosis / Q000235:genetics* / Q000601:surgery; D009508:Nevus, Pigmented / Q000175:diagnosis / Q000235:genetics* / Q000601:surgery; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics / Q000378:metabolism; D012867:Skin / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000601:surgery; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism; D043222:Ubiquitin Thiolesterase / Q000235:genetics* / Q000378:metabolism
chemical_list: C400134:BAP1 protein, human; D014408:Biomarkers, Tumor; D008565:Membrane Proteins; D025521:Tumor Suppressor Proteins; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D043222:Ubiquitin Thiolesterase; D020558:GTP Phosphohydrolases; C579846:NRAS protein, human