Fibroadenoma of the axillary ectopic breast tissue mimicking tuberculous lymphadenopathy: A case report and review of literature

Background Ectopic breast tissue (EBT) is an embryological anomaly occurring in 0.4–6% of the population due to incomplete regression of the mammary ridge. While frequently asymptomatic, EBT can harbor the same pathologies as orthotopic breast tissue. This review addresses the “diagnostic conundrum” of axillary EBT, which is often misidentified as lymphadenopathy, especially in regions with a high burden of tuberculosis. Methods We present an illustrative case of an axillary fibroadenoma in a 23-year-old female with a history of cervical tuberculosis, alongside a systematic review of cases from the literature to evaluate diagnostic pathways and clinical outcomes. Case Presentation A 23-year-old female presented with a persistent, non-tender right axillary mass. Given her history of treated cervical tuberculous lymphadenopathy, initial suspicion favored nodal pathology. Ultrasonography revealed a heterogeneous hypoechoic lesion. Following the proposed diagnostic algorithm, an FNAC suggested fibroadenoma, and surgical excision was performed. Histopathology confirmed a fibroadenoma arising within ectopic breast tissue. Discussion Modern anatomical evidence challenges the traditional “Axillary Tail of Spence” theory, favoring the concept of isolated segmental primordia along the milk line. Our review highlights that while USG and FNAC are primary tools, dynamic contrast-enhanced MRI serves as a crucial adjunct for inconclusive cases. The “TB distractor” remains a significant cause of misdiagnosis in endemic areas. Conclusions Fibroadenoma in axillary EBT must be included in the differential diagnosis of axillary swellings in reproductive-age women. A structured diagnostic approach, moving from USG to FNAC and, if necessary, MRI ensures accurate diagnosis and prevents inappropriate treatment.