A case of ectopic fibroadenoma mimicking left axillary lymphadenopathy

Fibroadenomas are the most common benign tumors of the breast. Since they originate from the fibroglandular breast tissue, they cannot be localized anywhere outside the breast. However, they can be localized in accessory or ectopic breast tissue and cause confusion in terms of clinical differential diagnosis. Small ectopic fibroadenomas placed in normal breast tissue are generally asymptomatic and nonpalpable. In contrast, lesions located in the axillary region are usually palpable, due to their superficial location and skin that is thinner at this level. This case report presents the clinical and imaging findings of a patient with a preliminary diagnosis of lymphadenopathy, with a superficial axillary location of the lesion and who underwent biopsy. In our case, no obvious accessory breast tissue was detected by physical examination or ultrasound of the left armpit. Even though there was axillary accessory breast tissue, it was not at a level that could be detected by ultrasound.