Axillary Ectopic Carcinoma of the Breast. Report of Two Cases with Different Clinical Presentation and Review of the Literature.

Aims: Primary ectopic breast cancer (PEBC) is a rare and often misdiagnosed condition. Through the discussion of two clinical cases, we want to focus on clinical presentation, outcomes and treatment of PEBC, to lead clinicians to awareness and optimal management. Methods: We present the case of a 47-year-old patient, with a 30 mm axillary mass, that was diagnosed as a PEBC (infiltrating lobular carcinoma, triple negative). The patient underwent systemic staging: diffuse metastatic bone lesions and leptomeningeal metastasis were found. The second patient is a 73-year-old woman with personal history of right breast tumor. She came to our attention for a 9 mm left axillary mass, suspicious for a metastatic lymph node. A fine-needle cytology revealed the absence of lymphoid cells but the presence of atypical epithelial cells, as in a primary breast carcinoma. She was treated with local excision and sentinel node biopsy. Results: The first patient presented with metastatic disease at the time of diagnosis and she deceased after three months from the diagnosis, despite systemic chemotherapy. The diagnosis was performed at an early stage in the second patient. She underwent surgery, complementary endocrine therapy and radiotherapy. She has no evident disease after two years from surgery. Conclusion: Primary ectopic breast cancer is a rare clinical entity, often misdiagnosed or diagnosed with a long delay. The treatment of PEBC is analogous to that of orthotopic breast cancer, but we strongly recommend to approach the patient with a multidisciplinary team to provide the best staging workout and therapie