Axillary Ectopic Breast Tissue Presenting With Cyclical Swelling: A Case Study

Ectopic breast tissue (EBT) is a rare condition characterized by the presence of abnormal additional breast tissue outside the typical pectoral region, typically along the mammary/milk lines. Although often asymptomatic, EBT can present as a palpable mass in areas such as the axilla, abdomen, or groin and may exhibit cyclical swelling in response to hormonal fluctuations. We report a case of a female patient, age 19, who complained of a palpable tumor in her right axilla. The tumor was linked to sporadic edema that coincided with her menstrual cycle. She had no prior surgical history and denied experiencing any other symptoms, such as discomfort, fever, weight loss, and systemic issues. Ultrasound imaging revealed glandular tissue consistent with EBT. The patient underwent surgical excision of the mass without complication. This case emphasizes the need to include EBT in the differential diagnosis of axillary tumors, especially those with cyclical alterations. Furthermore, it underscores the importance of good imaging in ensuring correct diagnosis and guiding effective treatment, which in this case involved surgical excision of the mass.