From the Guidelines
Breast tissue in the armpit, also known as axillary breast tissue, is a normal anatomical variation that requires evaluation by a healthcare provider if a lump or swelling is noticed, as it can develop conditions such as cysts, inflammation, or rarely, cancer. This tissue is part of the breast's tail (called the tail of Spence) and can become more noticeable during hormonal changes such as puberty, pregnancy, or menstruation. According to the most recent study 1, a palpable axillary lump has a wide differential diagnosis, ranging from nonmalignant etiologies to primary breast malignancy or metastatic disease from a nonbreast malignancy or lymphoma.
Key Points to Consider
- The presence of axillary breast tissue is due to embryological development, where breast tissue forms along "milk lines" extending from the armpit to the groin, and sometimes not all tissue regresses completely during development.
- If a lump or swelling is noticed in the armpit area, it is recommended to have it evaluated by a healthcare provider, though most cases are benign.
- During breast self-exams, it is essential to check the armpit area as well, since breast tissue in the armpit can develop the same conditions as the main breast tissue.
- No specific treatment is needed for normal axillary breast tissue unless it causes discomfort or cosmetic concerns, in which case surgical removal might be an option.
- The American College of Radiology recommends imaging of the axilla, including ultrasound and breast MRI, to evaluate the breast for underlying lesions in the setting of patients presenting with axillary lymphadenopathy 1.
Recommendations
- If a lump or swelling is noticed in the armpit area, it is crucial to have it evaluated by a healthcare provider.
- Imaging of the axilla, including ultrasound and breast MRI, should be performed to evaluate the breast for underlying lesions in the setting of patients presenting with axillary lymphadenopathy 1.
- Surgical removal of the axillary breast tissue may be considered if it causes discomfort or cosmetic concerns.
From the Research
Breast Tissue in Armpit
- Breast tissue can be found in the armpit, and its presence can be evaluated using various imaging modalities, including ultrasound and MRI 2, 3, 4, 5, 6.
- The evaluation of palpable breast abnormalities, including those in the armpit, typically involves ultrasound as the primary imaging tool, especially in women under 30 years old or those who are pregnant or lactating 2.
- For women over 40 years old, mammography followed by ultrasound is usually recommended for evaluating palpable breast abnormalities, including those in the armpit 2.
- MRI can be used to detect and evaluate breast tissue in the armpit, especially in cases where ultrasound or mammography is inconclusive or unable to detect the abnormality 3, 5, 6.
- MRI-guided biopsy can be performed to obtain a diagnosis of breast tissue in the armpit, especially if the abnormality is not detectable by other imaging modalities 3, 5, 6.
- The accuracy of MRI-directed ultrasound and subsequent ultrasound-guided biopsy for suspicious breast MRI findings, including those in the armpit, has been evaluated, and the results show that while MRI-directed ultrasound is a reliable method, there can be a significant inaccuracy rate for MRI-directed ultrasound-guided biopsy 5.