METAPLASTIC CARCINOMAS OF THE BREAST - FINE-NEEDLE ASPIRATION (FNA) CYTOLOGY FINDINGS

Metaplastic carcinomas of the breast are defined by mesenchymal and/or squamous cell components associated with ductal carcinoma and may rai se diagnostic problems in FNA cytology. We reviewed FNA smears of a se ries of nine cases; seven were compared with histological sections and two with cell-block sections. The cytological pattern was diagnostic of carcinoma in six cases; in two cases a diagnosis of sarcoma/phyllod es tumour was considered, as cells were predominantly spindle-shaped. One case had a pleomorphic adenoma type pattern. The cytological findi ngs suggesting a diagnosis of metaplastic carcinoma include a liquid a spirate, a proteinaceous or chondromyxoid background and a poorly diff erentiated tumour with multinucleated giant cells, neoplastic or histi ocytic. A definite diagnosis requires the presence of both carcinomato us and metaplastic (squamous/mesenchymal) components.