Signet-ring cell carcinoma of the breast with uterine metastasis treated with extensive cytoreductive surgery: a case report and brief review of the literature

The "Forgotten" Subtypes of Breast Carcinoma: A Systematic Review of Selected Histological Variants Not Included or Not Recognized as Distinct Entities in the Current World Health Organization Classification of Breast Tumors

Breast carcinoma is the most common cancer in women. Nineteen different subtypes of breast carcinomas are recognized in the current WHO classification of breast tumors. Except for these subtypes, there are a number of carcinomas with special morphologic and immunohistochemical features that are not included in the 5th WHO classification, while others are considered special morphologic patterns of invasive breast carcinoma of no special type. In this manuscript, we systematically review the literature on four different subtypes of invasive breast carcinoma, namely lymphoepithelioma-like breast carcinoma, breast carcinoma with osteoclast-like giant cells, signet-ring breast carcinoma, and metaplastic breast carcinoma with melanocytic differentiation. We describe their clinicopathological characteristics, focusing on the differential diagnosis, treatment, and prognosis.

Mucinous Proliferations of the Uterine Corpus: Comprehensive Appraisal of an Evolving Spectrum of Neoplasms

A variety of endometrial lesions may contain mucinous cells. Herein, the author reviews the literature on the classification and clinicopathologic significance of uterine corpus proliferations with a significant mucinous component, assesses the 2020 World Health Organization classification of such lesions, and presents a diagnostic framework. The key epithelial mucinous lesions include mucinous metaplasia, atypical mucinous glandular proliferation and mucinous carcinoma. Each of these categories are classifiable into "usual" and gastrointestinal subtypes, the latter being indicative of intestinal (presence of goblet cells) and/or gastric-type (abundant, pale eosinophilic or clear cytoplasm and well-defined cell borders) morphology. It has been proposed that at least focal expression of gastrointestinal immunohistochemical markers be required for all gastrointestinal type lesions, and for gastrointestinal type atypical mucinous glandular proliferation and carcinoma, minimality or absence of estrogen receptor expression, and the absence of an endometrioid component. Mucinous carcinomas of the usual type, in which >50% of the tumor is comprised of a mucinous component, are the most common. Morphologic subtypes include mucinous carcinoma with microglandular features and mucinous carcinoma with signet rings (signet ring carcinoma). Endometrioid carcinomas with a less than a 50% mucinous component are classified as endometrioid carcinoma with mucinous differentiation. Several studies have directly compared endometrioid and mucinous carcinomas, the latter presumably of the usual type, with respect to patient outcomes after treatment. All have found no difference in overall and disease free survival between these groups. However, three major studies have found mucinous carcinomas to be associated with a higher risk of lymph node metastases. Nineteen cases of mucinous carcinoma of the gastrointestinal type have been reported, and the limited data on their follow-up after primary treatment suggests that this subtype is more clinically aggressive and should accordingly be classified separately from mucinous carcinomas of the usual type. The morphologic spectrum of mucinous carcinoma of the gastrointestinal type is unclear and continues to evolve. Mucinous change, which may sometimes be extensive, may also be associated with papillary proliferation of the endometrium, adenomyoma of the endocervical type, atypical, and typical adenomyomas. In a curettage or biopsy, intestinal type mucinous epithelium may be indicative of any of the gastrointestinal lesions mentioned above, but may also represent samplings of uterine teratomas, yolk sac tumors, genital and extragenital adenocarcinomas with intestinal differentiation, or low-grade appendiceal mucinous neoplasms that secondarily involve the endometrium.

Prognostic Analysis of Primary Breast Signet Ring Cell Carcinoma and Mucinous Breast Adenocarcinoma: A SEER Population-Based Study

Background

Primary breast signet ring cell carcinoma (SRCC) is a rare type of breast cancer with typical morphological characteristics, high aggressiveness, and poor prognosis. SRCC is different from mucinous breast adenocarcinoma (MBC). However, only a few studies have explored the clinicopathological features and prognosis of SRCC and MBC.

Methods

Data retrieved from the Surveillance, Epidemiology, and End-Results (SEER) database (2004-2015) were used to explore the prognostic effect of clinicopathological features and treatment modalities on survival outcomes of SRCC and MBC patients. Kaplan-Meier plot analysis, multivariate Cox proportional risk model, propensity score matching (PSM), and subgroup analysis were performed.

Results

A total of 167 patients with SRCC and 11,648 patients with MBC were included in the study. SRCC patients exhibited higher histological grade (p < 0.001), larger tumor volume (p < 0.001), higher rate of lymph node metastasis (p < 0.001), and higher frequency of distal metastasis (p < 0.001) compared with MBC patients. Cox proportional hazards regression analysis showed that SRCC patients had lower overall survival (OS) and breast cancer-specific survival (BCSS) compared with MBC patients. Subgroup survival analysis showed that the SRCC patients had lower OS and BCSS in subgroups including younger than 60 years old, white race, married, without chemotherapy, and received radiotherapy compared with the MBC patients in these subgroups. In addition, the SRCC patients had lower BCSS in subgroups including other races (including Asian or Pacific Islander and American Indian/Alaska Native), without surgery, and lymph node metastasis.

Conclusion

The findings showed that primary breast SRCC patients have unique clinical characteristics and worse prognosis compared with MBC patients. Notably, different treatment methods resulted in different prognosis for SRCC and MBC types; therefore, SRCC patients should be distinguished from MBC patients to improve efficacy of treatment.