Metastasis of the Mucionous adenocarcinoma of breast to the mandibular gingiva: Rare case report

Mucinous adenocarcinoma (MAC) is a rare type of cancer in which more than 50% of the tumor is composed of extracellular mucin and malignant epithelial cells. MACs account for only 1.8% of all breast cancer cases. Most breast cancers present as localized diseases and are well-differentiated. Breast MAC has a better 5- and 10-year survival rate than ductal and lobular carcinomas. Distant metastasis in breast MAC is rare, especially in the oral cavity. Only 1% of all oral malignancies present with metastases to the oral cavity. The bony structures are more involved than the soft tissues. Involvement of the oral soft tissue is rare, accounting for less than 0.1% of oral metastases. CASE DESCRIPTION: This report describes a rare case of mucinous breast adenocarcinoma with metastasis to the mandibular molar region. Diagnosis was established based on anamnesis, clinical presentation, tumor biopsy, computed tomography, mammography, and core biopsy of the breast tumor. The patient was sent to the oncology committee for breast disease where chemotherapy was indicated. DISCUSSION: The clinical presentation of oral metastasis is not pathognomonic, and pyogenic granuloma, periodontal abscesses, sarcomas, and squamous carcinoma must be considered in the differential diagnosis. This is a rare case of oral metastasis of breast MAC, which was indicated for detection of the primary tumor.