title: Palisaded myofibroblastoma of the breast: a tumor closely mimicking schwannoma: Report of 2 cases.
abstract: Myofibroblastoma is a relatively rare, benign mesenchymal tumor that typically occurs in the breast parenchyma. Unlike mammary-type myofibroblastoma, myofibroblastoma that primarily arises in the lymph nodes exhibits nuclear palisading, and the term palisaded myofibroblastoma has been proposed, accordingly. We report 2 unusual cases of myofibroblastoma of the male breast, which showed a predominant (>90% of the entire tumor) nuclear palisading and Verocay-like bodies. The present cases represent a hitherto unreported variant of mammary-type myofibroblastoma closely mimicking schwannoma. The diagnosis of myofibroblastoma was supported by immunohistochemical analyses showing a diffuse staining for desmin and CD34. In addition, the diagnosis of myofibroblastoma was confirmed in 1 case cytogenetically by the demonstration of the monoallelic loss of the FOXO1/13q14 locus by fluorescence in situ hybridization. Pathologists should be aware of this unusual variant of mammary myofibroblastoma to assure a correct diagnosis.
authors.affiliation: Department G.F. Ingrassia, Azienda Ospedaliero-Universitaria Policlinico-Vittorio Emanuele Anatomic Pathology, University of Catania, 95123 Catania, Italy. g.magro@unict.it
authors.forename: Gaetano
authors.initials: G
authors.lastname: Magro
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Foschini
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Eusebi
mesh_terms: D000368:Aged; D018952:Antigens, CD34 / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D018567:Breast Neoplasms, Male / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002467:Cell Nucleus / Q000473:pathology; D004273:DNA, Neoplasm / Q000032:analysis; D003893:Desmin / Q000378:metabolism; D003937:Diagnosis, Differential; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009379:Neoplasms, Muscle Tissue / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D009442:Neurilemmoma / Q000175:diagnosis*; D016896:Treatment Outcome
chemical_list: D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D003893:Desmin; C085126:FOXO1 protein, human; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors
keywords: Breast; Fluorescence in situ hybridization; Immunohistochemistry; Myofibroblastoma; Schwannoma