Mucoepidermoid carcinoma-a rare salivary gland-type tumor of the breast: are we dealing with primary or secondary?-a case report and literature review

Background

Salivary gland-like tumors are extremely unusual in the breast, and their histology is very similar to primary salivary gland neoplasms. Mucoepidermoid carcinoma (MEC), a common salivary gland tumor, displays an infrequent occurrence in the breast, accounting for a mere 0.2-0.3% incidence. Given its rarity, it is critical to accurately distinguish it from metastatic cases before diagnosing it as a primary breast MEC for appropriate treatment. Currently, there is no consensus on the treatment of MEC, and there is a paucity of literature highlighting the ideal treatment modality, especially for estrogen receptor (ER)-positive cancers. Therefore, the aim of our case report was to underscore the diagnostic process, surgical and adjunctive treatments for our patient with ER-positive, progesterone receptor (PR)-negative and human epidermal growth factor receptor 2 (HER2)-negative MEC while also conducting a literature review to contribute to the limited existing data.

Case Description

A 67-year-old African American woman presented with a lobulated 3.1-cm left breast mass on mammography, for which she underwent ultrasound-guided core needle biopsy that revealed invasive carcinoma with squamous differentiation. The carcinoma was ER-positive, PR-negative and HER2-negative. Subsequently, she underwent a lumpectomy with sentinel lymph node biopsy. Her final pathology revealed an intermediate-grade MEC with negative lymph nodes. She had a past medical history of benign salivary gland tumor, as well as a family history of BReast CAncer gene 1 (BRCA1)-associated breast cancer in her daughter.

Conclusions

MEC of the breast is a rare tumor with a relatively favorable overall prognosis. The early and precise diagnosis of this condition plays a pivotal role in formulating effective treatment strategies and ensuring positive survival rates. Nonetheless, future studies are recommended to further explore the role of surgical approaches and adjuvant therapy to improve treatment outcomes.

Mucoepidermoid carcinoma of the breast, 3 cases report and literature review

RATIONALE

Mucoepidermoid carcinoma (MEC) is one of the most common malignant tumors in salivary glands, with specific histomorphological and molecular characteristics. MEC occurring in breast is more rare.

PATIENT CONCERNS

We reported 3 cases of female breast mass, diagnosed as benign nodules by ultrasound.

DIAGNOSES

The first 2 cases were pathological diagnosed as breast MEC, low grade, and the third case as breast MEC, medium grade.

INTERVENTIONS

After pathological diagnosis, 3 patients have expanded the scope of breast resection and lymph node dissection, with negative margin and no lymph node metastasis.

OUTCOMES

In the follow-up observation, the first case was followed up for 24 months, the second case was followed up for 30 months, and the third case was followed up for 12 months. All patients had a good prognosis without evidence of recurrence and metastasis.

CONCLUSION

Breast MEC is extremely rare and estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 negative breast cancer with a good prognosis, which is different from other highly malignant triple-negative breast cancers. reviewed its clinicopathologic morphological characteristics, immunohistochemical markers and molecular characteristics, prognosis and clinical treatment through literature, in order to understanding its clinicopathology and providing reference for clinical precise treatment.

Breast mucoepidermoid carcinoma: a case report and review of literature

Breast mucoepidermoid carcinoma (MEC) is clinically rare, with an estimated incidence of 0.2-0.3% of all primary breast tumors. To date, only 41 cases have been reported in the literature. Herein, we present a case of breast MEC diagnosed at our hospital. The clinicopathologic features were preliminarily discussed by reviewing the literature. A 42-year-old Chinese woman presented with a lump in her right breast that was detected approximately three months prior. A microscopic examination showed that the breast MEC was composed of different proportions of mucinous cells, intermediate cells, and epidermoid cells. Most mucinous cells were positive for cytokeratin 7, while the epidermoid and intermediate cells were positive for p63 and cytokeratin 5/6. All tumor cells were negative for other myoepithelial markers, such as calponin. Tumor cells did not express estrogen, progesterone, or the HER-2/neu protein. After the patient underwent mastectomy, she was diagnosed with a low-grade mucoepidermoid carcinoma based on the clinical, histologic, and immuno-phenotypic characteristics. Our findings provide further insight into the pathologic mechanism of MEC, as correct diagnosis is essential for patient management.