Metastatic mucinous adenocarcinoma from breast mimicking a pyogenic granuloma in the gingiva: a case report.

Mucin-producing adenocarcinomas (MAC) are an extremely rare, indistinct group of neoplasm having either a salivary gland origin or with prominent glandular component. The diagnosis is chiefly based on the histological aspect conjoined with immunohistochemical evaluation as clinico-radiographical features are non-specific. It can arise as a primary metastasis to soft tissues, most commonly from either lung, breast, kidney, or colon. This paper reports a 51-year-old woman with buccolingual gingival swelling having a final diagnosis of metastatic mucinous adenocarcinoma from the breast. A tissue biopsy was performed followed by immunohistochemistry that confirmed the diagnosis. They are extremely rare, making the diagnosis challenging as it may mimic a benign neoplasm. It accounts for approximately 1% of all oral malignant neoplasms having gingival propensity. The clinician should therefore take into account every diagnostic aspect while encountering such oral lesions to achieve proper patient welfare.