Fine-needle aspiration cytology of metaplastic carcinoma of the breast

摘要

Background: Metaplastic carcinoma of the breast encompasses a heterogeneous group of tumours withrnvariable components of sarcomatoid, squamous or poorly differentiated carcinomas. Aim: To review a series of 19 cytological preparations of metaplastic carcinomas to assess diagnosticrncytological features. Methods: 17 cases of fine-needle aspirates of histologically proven metaplastic carcinomas (4 monophasicrnspindle cell carcinomas, 4 squamous cell carcinomas and 11 biphasic tumours) were reviewed, with anrnemphasis on the presence of poorly differentiated carcinoma, squamous cell carcinoma, atypical spindlerncells, benign stromal fragments and necrosis. Results: All cases were diagnosed as malignant, with 68% of cases showing moderate to high cellularity, and 47%rnshowing necrosis. If the tumours were analysed according to the constituting components histologically, 7,15 andrn8 cases, respectively, possess poorly differentiated carcinoma cells, sarcomatoid malignant cells and squamousrncarcinoma cells, whereas these components were cytologically identified in 11,10 and 7 cases, respectively. Dualrntumour populations were identified in only 5 of the 11 biphasic carcinomas in the cytological preparations; andrnthe stromal material was cytologically identified in the only case with chondroid stroma. Conclusions: Identification of metaplastic carcinoma in cytology remains problematic. There seems to bernmorphological overlap between various components. The identification of dual components, unequivocalrnsquamous carcinoma cells and chondroid stroma is helpful for diagnosis, but it is uncommon. The presence ofrnpoorly differentiated carcinoma cells with a suggestion of focal spindle morphology is another clue to thernsuggestion of metaplastic carcinoma.