Occult breast cancer presenting as axillary lymphadenopathy – Case Report

INTRODUCTION: Occult breast carcinoma (OBC) is a rare entity and therefore generates discussion regarding diagnosis, approach, and prognosis. This article aims to present a case of OBC and reviews some concepts discussed in the literature. PRESENTATION OF CASE: 43-year-old woman with right axillary adenopathies, without further complaints, whose biopsy shows a lymph node metastasis from invasive ductal carcinoma of the breast. Breast study, breast RMI and FDG-PET did not identify the primary tumour. As decided by a multidisciplinary team, the patient underwent neoadjuvant chemotherapy, axillary surgery, breast radiotherapy and hormone therapy. Four years after surgery, the patient has no evidence of the primary tumour and no axillary recurrence. DISCUSSION: OBC was described in 1907. Although the best therapeutic approach is widely discussed in the literature, it is consensual that as long as the existence of a primary tumour is excluded by breast MRI, the conservative approach (excision of axillary adenopathy and breast and axillary radiotherapy) is more advocated. CONCLUSION: Breast cancer must be considered in the differential diagnosis of a patient with axillary lymphadenopathy. The conservative approach of OBC is the preferred since breast MRI does not identify any suspicious lumps.