Fine needle aspiration of myofibroblastoma of the breast. Case report.

The cytologic and histologic findings of myofibroblastoma of a man's breast are reported. Cytologic specimens showed many scarcely cohesive clusters of bipolar or stellate cells. The cytoplasm was moderately eosinophilic and had clearly-defined edges. The nucleus was characterized by round or coffee-bean shape, regular chromatin and small nucleolus. Atypical features were absent. Immunocytochemical tests confirmed the mesenchymal nature of the lesion showing negativity for CAM 5.2 and positivity for vimentin. We stress the value of fine-needle aspiration biopsy in association with clinical- examination, mammography and/or echography in establishing the preoperative diagnosis of this benign tumor.