Aspiration cytology of cystic carcinoma of the breast.

Cystic carcinomas of the breast are rarely encountered in fine-needle aspiration (FNA) biopsies. The most common entities comprise intracystic papillary adenocarcinoma, ductal adenocarcinoma with cystic degeneration including comedo forms of ductal adenocarcinoma in situ, medullary carcinoma, squamous carcinoma, and cystic hypersecretory ductal adenocarcinoma. The cytologic diagnosis is often hampered by sparse cellularity, abundant obscuring blood, necrotic debris, and degenerative changes in diagnostic cells. We report on the cytologic features of 10 cases of cystic carcinoma, including 12 FNA biopsies with radiologic and surgical correlation. The original cytologic diagnoses for these cases were: benign (2 cases), atypical (2 cases), suspicious (3 cases), and positive for malignant cells (3 cases). On repeat FNA, one benign case and one atypical case were reclassified, respectively, as atypical and suspicious for carcinoma. The follow-up diagnoses were 5 intracystic papillary adenocarcinomas and 5 cystic ductal adenocarcinomas. Despite 2 false-negative cases, all cases were adequately managed. Correlation with clinical and radiologic findings and direct sampling of any solid component of these cystic neoplasms are crucial in diagnosis and management.