Analysis of metaplastic breast carcinoma: FNAC; histopathology and immunohistochemistry are complementary for diagnosis.
BACKGROUND
Metaplastic breast carcinoma (MBC) is a rare malignancy comprised of ductal, squamous and/or mesenchymal elements with problematic diagnosis.


OBJECTIVE
This study analyses MBC identifying its cytologic and histologic features and emphasizing the combined role of FNAC, histopathology and immunohistochemistry (IHC) in its diagnosis.


METHODS
Cytology and histopathology files search yielded 21 cases identified as MBC from January 2005 to December 2010. FNAC and the histopathology slides were re-examined for the presence and frequency of various elements. Cytological and histopathological diagnoses were made and the cases subtyped according to WHO classification. Cytokeratin and vimenten IHC were used to confirm diagnosis when required.


RESULTS
On FNAC, 52.4% were diagnosed as malignant, 9.5% as suspicious for malignancy and 38.1% as benign lesions. Most frequent cytologic findings were squamous and spindle cell elements (52.4% each). Histopathology revealed 76.2% pure epithelial tumors and 23.8% mixed epithelial-mesenchymal tumors. Squamous cell carcinoma was the most frequent histological subtype (33.3%). Carcinosarcomas were dimorphic on IHC& spindle cell carcinomas were positive for both cytokeratin and vimentin.


CONCLUSIONS
Presence of dual components, squamous, spindle elements, mesenchymal fragments and necrosis in moderate to high cellularity breast FNAC provides clues for the diagnosis of MBC. FNAC; histopathology and IHC complement for diagnosis.
Pathology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
Amal
A
Abd El Hafez
Abd El-Aty
Ael-A
Shawky
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D044963:Biopsy, Fine-Needle; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D018196:Carcinoma, Adenosquamous / Q000378:metabolism / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D012189:Retrospective Studies; D012509:Sarcoma / Q000378:metabolism / Q000473:pathology*
D014408:Biomarkers, Tumor
FNAC; IHC; Metaplastic breast carcinoma; histopathology; spindle cell; squamous cell