Clinicopathological Study of Mucinous Carcinoma of Breast with Emphasis on Cytological Features: A Study at Tertiary Care Teaching Hospital of South India

Abstract

Introduction Mucinous carcinoma (MC) is a rare form of breast cancer. It accounts for 1 to 7% of the cases and characterized by the presence of extracellular mucin (ECM). Depending on the amount of mucin, it is classified into pure mucinous carcinoma (> 90%, PMC) and mixed mucinous carcinoma (MMC; < 90%). In comparison to most common subtypes, MC is having better prognosis. There exist clinicopathological differences among PMC and MMC and also MC and IDC-NOS. Materials and Methods MCs diagnosed between January 2012 and December 2017 were included. Fine needle aspiration cytology smears were screened for cellularity, ECM, nuclear pleomorphism, signet ring cells (SRC), mucinophages, and myxovascular fragments (MVF). Histopathology slides were screened to confirm the diagnosis. Immunohistochemistry slides were graded as per the standard protocol. Statistical analyses were performed by SPSS software. Results In the present study, MC constituted 3.3%. The mean age of the patients was 50.9 years. ECM, mucinophages, and SRC were the key diagnostic cytological features. The PMC and MMC were clinicopathologically distinct with respect to gross findings and lymph node status. MMCs were highly proliferative. The mean duration of follow-up was 24.5 months. Complications were more common in MMC than PMC. Lymph node involvement is the key prognostic factor and it is independent of other prognostic factors like age, size, and hormonal receptor status. Conclusion PMC are rare subtype of breast cancer. The diagnostic cytological features are ECM, MVF, and SRC. MMC and PMC are clinicopathologically and genetically distinct.

Pure Mucinous Breast Carcinoma With a Favorable Tumor Biology and Clinical Outcomes

“…MMBCs were highly proliferative, with more complications compared to PMBC. Lymph node involvement is the most important prognostic factor, and it is independent of other prognostic factors, such as tumor size, patient age, and hormonal receptor status (24). According to our findings, lymph node involvement, mean tumor diameter, high Ki67 expression, and HER2 positivity were all significantly increased in the group under 50 years old.…”

Pleomorphic adenoma of the breast with cytologic atypia on cytopathology: A potential diagnostic pitfall and literature review

“… 8 Other case studies have described hypercellular FNA smears with epithelial and spindled cells in a myxoid matrix or large epithelial cells with occasional large, bizarre cells 11,15 . In this case, the presence of cells with cytological atypia, the absence of breast myoepithelial cells, single cells and the background material were all suggestive of mucinous carcinoma 19 . Complicating this picture is that mucinous carcinoma may also present as a well‐circumscribed mass in the breast 20 …”

“…11,15 In this case, the presence of cells with cytological atypia, the absence of breast myoepithelial cells, single cells and the background material were all suggestive of mucinous carcinoma. 19 Complicating this picture is that mucinous carcinoma may also present as a well-circumscribed mass in the breast. 20 Retrospectively, this case showed three features which could have permitted the distinction of PA from mucinous carcinoma.…”

Metachronous Mucinous Breast Carcinoma and Mucinous Pancreatic Cystadenoma in a Patient With Metabolic Comorbidities- Case Report and Minireview

“…Mucinous breast carcinoma, characterized morphologically by clusters of tumor cells aggregated in an extracellular mucin-rich environment [27], can appear in two forms: pure or mixed, depending on the proportion of the mucinous component [28][29][30][31]. The presence of mucin creates a collector environment for tumor cells and reduces the mobility of tumor cells, leading to fewer metastases and explaining the more favorable prognosis [32]. The distinction between these subtypes is based on the quantification of cellularity.…”