Fine needle aspiration cytology of signet ring cells in breast carcinoma: a cytohistological study of 11 cases

Signet ring cell (SRC) carcinoma is a unique subtype of adenocarcinoma; however, the clinicopathological profiles of SRCs in breast carcinoma are yet to be determined. Here, we investigated cyto-histological findings of 11 breast carcinoma cases with SRCs comprising more than 20% of the tumor cells; invasive ductal carcinoma (IDC) (n=4), invasive lobular carcinoma (ILC) (n=4), pleomorphic lobular carcinoma (PLC) (n=1), and mucinous carcinoma (MC) (n=2). The mean age of the patients was 60.2 ± 13 years, and the mean tumor size was 2.0 ± 0.8 cm. Three cases of IDC, 1 PLC, and 1 of MC had grade 2 or 3 nuclear atypia, whereas 1 case of IDC, 4 of ILC, and 1 of MC had grade 1 nuclear atypia. Axillary lymph nodes were positive for metastatic carcinoma in 1 patient with IDC and 1 with ILC. In fine needle aspiration smears, intracytoplasmic lumen (ICL) type SRCs were found to be major constituents of SRCs in ILC and PLC, while non-ICL type SRCs were predominant in IDC. MC tumors had SRCs of both ICL and nonICL types. During our follow-up period ranging from 97 to 3650 (mean 1458 ± 1055) days, all the patients were alive without recurrence of the tumor. Our results indicate that the nature of SRCs may vary with the histological subtype of breast cancer, but its presence may not indicate poor prognosis. A large study with more cases of breast cancer with SRCs for a longer period may be needed to determine the clinical significance of SRCs.