Fine-needle aspiration cytology of suture granulomas of the breast: a potential pitfall in the cytologic diagnosis of recurrent breast cancer.

The fine-needle aspirates of three cases of suture granulomas of the breast area following mastectomy, lumpectomy, or axillary node dissection were reviewed. The original histologic diagnoses were mucinous (colloid) carcinoma, intraductal carcinoma, and low-grade phyllodes tumor. In two patients a new nodule developed in the surgical scar, and in the third a nodule developed in the axilla 2 cm away from the scar. The cellularity of the aspirates ranged from low to moderate, and all three cases contained variable numbers of spindled cells and fragments of cellular stroma. Multinucleated giant cells characteristic of suture granulomas were absent in all cases. Abundant metachromatic amorphous background material was present in one case, which was interpreted as recurrent mucinous carcinoma. The remaining cases were interpreted as suspicious for recurrent neoplasm. Upon excision, all were suture granulomas with fibroblastic proliferation. Suture granulomas can both clinically and cytologically mimic recurrent malignancy. The predominance of spindled cells and dissimilarity to the original tumor appear to be the most helpful features to cytologically distinguish suture granuloma from recurrent carcinoma in the absence of the characteristic multinucleated giant cells.