Fine-Needle Aspiration Cytology of Mammary Myofibroblastoma: A Report of Six Cases

Objective: To evaluate cytologic features of mammary myofibroblastoma in order to establish the possibility of precise preoperative recognition. Study Design: This was a multi-institutional study of 6 patients with myofibroblastoma (5 men and 1 woman) in which preoperatively fine-needle aspiration cytology was performed. Four cases showed classical histologic features, 1 corresponded to the cellular variant and the remaining 1 to the fibrous form. Results: Except for 1 case, smears were cellular and distributed as irregular aggregates and single cells. Most groups showed a small amount of metachromatic stroma and capillaries. Cells retained cytoplasm and showed a spindle-to-plump oval morphology with moderate pleomorphism. Nuclear pleomorphism was present and was relevant in 1 case. Intranuclear pseudoinclusions and mast cells were present in 3 cases. No epithelial clusters were seen. Due to hypercellularity and pleomorphism 1 case was considered as suspicious for malignancy. The remaining 5 were diagnosed as low-grade mesenchymal lesions, and myofibroblastoma was suggested in 3. Conclusion: Cytologic features of myofibroblastoma reflect what is seen on histology. When such findings are correlated with image studies, preoperative recognition can be possible. This is especially true for male patients in whom the tumor is relatively frequent. Copyright (C) 2012 S. Karger AG, Basel