title: S100 expression by atypical megakaryocytes: a previously unreported potential pitfall in dermatopathology.
abstract: Several types of large atypical epithelioid cells can mimic tumoral melanocytes and can therefore be a source of misdiagnosis of melanoma. Megakaryocytes are one of these types, and are not frequently mentioned in the literature. In the current report, we present the case of a 76-year-old man presenting with acute panmyelosis with myelofibrosis. The bone marrow biopsy contained atypical megakaryocytes that expressed S100 in the cytoplasm. We discuss how such aberrant expression could be a source of some diagnostic problems in dermatopathology, including cutaneous melanoma, metastasis of melanoma in bone marrow and metastasis of melanoma in sentinel lymph nodes.
authors.affiliation: Department of Cellular Pathology, Hospital El Bierzo, Ponferrada, Spain.
authors.forename: Angel
authors.initials: A
authors.lastname: Fernandez-Flores
authors.forename: Francisco-Javier
authors.initials: FJ
authors.lastname: Díaz-Galvez
mesh_terms: D000368:Aged; D001706:Biopsy; D001853:Bone Marrow / Q000378:metabolism / Q000473:pathology; D003593:Cytoplasm / Q000378:metabolism; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D008533:Megakaryocytes / Q000378:metabolism* / Q000473:pathology*; D055728:Primary Myelofibrosis / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*; D009418:S100 Proteins / Q000096:biosynthesis*
chemical_list: D009418:S100 Proteins
keywords: acute panmyelosis with myelofibrosis; bone marrow; metastatic melanoma