title: Malignant fibrous histiocytoma, giant cell type, of the breast mimicking metaplastic carcinoma. A case report.
abstract: BACKGROUND
  We report a case of malignant fibrous histiocytoma, giant cell type (MFHGC), of the breast. A review of the literature failed to reveal cytology-based reports on this entity. The cytologic similarity of breast MFHGC on fine needle aspiration biopsy (FNAB) to other malignant breast neoplasms, including carcinoma with osteoclastlike giant cells, metaplastic carcinoma and breast sarcomas, as well as benign reactive processes, makes the recognition of this tumor challenging.
  
  
  METHODS
  A 72-year-old woman presented with a 5-month history of an enlarging breast mass. FNAB of the mass showed a hypercellular smear composed of cohesive, branching clusters of spindle cells with ovoid, focally hyperchromatic nuclei and inconspicuous nucleoli. Interspersed osteoclastlike giant cells, some associated with clusters of spindle cells, were uniformly seen throughout the smear. The background was hemorrhagic, with cellular debris and occasional spindle cells and lymphocytes. No ductal epithelial or myoepithelial cells were seen. An incisional biopsy was performed, followed by radical mastectomy. The histologic examination was diagnostic of MFHGC. The diagnosis was supported by immunohistochemical and electron microscopic studies.
  
  
  CONCLUSIONS
  MFHGC, also called primary giant cell tumor of soft tissues, is composed of a mixture of histiocytes, fibroblasts and bland-appearing osteoclastlike giant cells with a multinodular growth pattern. Although MFHGC rarely occurs in the breast and the definitive diagnosis is difficult based on cytology alone, the diagnosis can be considered when a cytologic examination reveals a hypercellular, spindle cell smear with osteoclastlike giant cells in the absence of ductal epithelial or myoepithelial cells.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of California-Los Angeles Medical Center, CHS A7-149, 10833 LeConte Avenue, Los Angeles, California 90095-1732, USA. swiriosuparto@mednet.ucla.edu
authors.forename: Sony
authors.initials: S
authors.lastname: Wiriosuparto
authors.forename: Nina
authors.initials: N
authors.lastname: Krassilnik
authors.forename: Adrian
authors.initials: A
authors.lastname: Gologan
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Cohen
authors.forename: Bruce
authors.initials: B
authors.lastname: Wenig
mesh_terms: D000368:Aged; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000473:pathology* / Q000648:ultrastructure; D002277:Carcinoma / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D005870:Giant Cell Tumors / Q000473:pathology* / Q000648:ultrastructure; D018219:Histiocytoma, Benign Fibrous / Q000473:pathology* / Q000648:ultrastructure; D006801:Humans; D002479:Inclusion Bodies / Q000473:pathology / Q000648:ultrastructure; D008247:Lysosomes / Q000473:pathology / Q000648:ultrastructure; D008679:Metaplasia / Q000473:pathology; D008854:Microscopy, Electron; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D014408:Biomarkers, Tumor; C067980:CD68 antigen, human; D000097382:CD68 Molecule