Differential Diagnosis for Left Breast Pain and Lump
- Single most likely diagnosis
- Breast cyst: The patient's presentation of a painful, mobile breast lump that is sensitive to touch, along with ultrasound findings of a well-circumscribed anechoic structure and resolution of the mass after needle aspiration yielding clear fluid, is highly suggestive of a breast cyst. Breast cysts are common in women of reproductive age and are often tender and fluctuant.
- Other Likely diagnoses
- Fibroadenoma: Although less likely given the fluid-filled nature of the mass, fibroadenomas can present as mobile, painless or slightly tender breast lumps. They are common in young women but are typically solid on ultrasound.
- Breast abscess: While the absence of infection signs (such as fever, erythema, or purulent discharge) and the clear fluid aspirate make this less likely, a breast abscess could present with a painful lump. However, abscesses usually have a thicker wall and may show Doppler enhancement due to inflammation.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Phyllodes tumor: Although rare, phyllodes tumors can grow rapidly and may present as large, mobile breast masses. They can be benign, borderline, or malignant, and their diagnosis requires histological examination. The rapid growth and size of the mass in this patient, despite its benign appearance on ultrasound, necessitate consideration of this diagnosis.
- Breast cancer: Given the family history of breast cancer, it's essential to consider malignancy, even though the ultrasound characteristics and aspiration results are not suggestive of cancer. Any solid component or irregularity not fully explained by the initial findings would warrant further investigation, including biopsy.
- Rare diagnoses
- Galactocele: A milk-filled cyst that can occur in lactating women but is rare in nulligravid women. The presentation could be similar, but the fluid aspirate would be milky rather than clear.
- Hematoma or seroma: These could present as fluid-filled masses but are typically associated with trauma or recent surgery, neither of which is mentioned in the patient's history.
- Fat necrosis: This can mimic a breast tumor and may result from trauma to the breast. However, it usually presents with a more complex appearance on imaging and may not resolve with simple aspiration.