title: Multiple epithelioid Spitz nevi or tumors with loss of BAP1 expression: a clue to a hereditary tumor syndrome.
abstract: OBJECTIVE
  Recently, a group of melanocytic tumors with loss of BAP1 expression has been described. The lesions may occur sporadically or as part of a familial cancer syndrome. They have distinct histopathologic features characterized by a nevus like silhouette and cytologic composition of large epithelioid melanocytes with oval vesicular nuclei, distinct nucleoli, and abundant cytoplasm. The large melanocytes are immunohistochemically characterized by loss of nuclear labeling for BAP1.
  
  
  METHODS
  We describe a 21-year-old patient with multiple combined melanocytic proliferations composed of both a nevus component with strong BAP1 expression and a large epithelioid melanocyte population with loss of BAP1 expression. The occurrence of multiple BAP1 loss melanocytic lesions raised concerns about a possible germline mutation. Sequence analysis of DNA from lesional and nonlesional skin confirmed a BAP1 germline mutation.
  
  
  CONCLUSIONS
  The presence of multiple clinically banal-appearing melanocytic lesions with childhood onset suggests that the combined lesions with BAP1 loss large epithelioid melanocytes described herein are probably combined nevi. Our findings also illustrate how the detection of a histopathologically distinct melanocytic lesion, coupled with knowledge of its possible association with a hereditary tumor syndrome, can lead to the suspicion and confirmation of a germline mutation.
authors.affiliation: Department of Pathology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065, USA. busamk@mskcc.org
authors.forename: Klaus J
authors.initials: KJ
authors.lastname: Busam
authors.forename: Michelle
authors.initials: M
authors.lastname: Wanna
authors.forename: Thomas
authors.initials: T
authors.lastname: Wiesner
mesh_terms: D015622:Epithelioid Cells / Q000378:metabolism / Q000473:pathology; D015971:Gene Expression Regulation, Enzymologic; D018095:Germ-Line Mutation; D006801:Humans; D008297:Male; D008544:Melanocytes / Q000378:metabolism / Q000473:pathology; D018332:Nevus, Epithelioid and Spindle Cell / Q000235:genetics* / Q000473:pathology; D017422:Sequence Analysis, DNA; D012878:Skin Neoplasms / Q000235:genetics* / Q000473:pathology; D025521:Tumor Suppressor Proteins / Q000235:genetics*; D043222:Ubiquitin Thiolesterase / Q000235:genetics*; D055815:Young Adult
chemical_list: C400134:BAP1 protein, human; D025521:Tumor Suppressor Proteins; D043222:Ubiquitin Thiolesterase