A 29-year-old nulligravid woman comes to the office due to left breast pain. She noticed a painful left breast lump last week while in the shower. The lump is very sensitive to touch, making wearing a bra uncomfortable. The patient has no medical conditions and has had no prior surgeries. Family history is significant for a cousin with breast cancer. Vital signs are normal. Physical examination reveals a 4 × 5 × 6 cm mobile mass in the left breast. Ultrasound shows a well-circumscribed anechoic structure with a thin wall and no Doppler enhancement. No echogenic debris or solid components are seen. Needle aspiration yields clear fluid with resolution of the mass. Which of the following is the best next step in management of this patient?
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This patient's unilateral, tender breast mass is consistent with a simple breast cyst, a benign breast disorder that usually occurs in women age 30-50. Presentations are variable, ranging from asymptomatic to severely painful. Whether or not they cause pain, breast cysts typically have noninvasive features on examination: they are mobile, smooth, and well-circumscribed; associated tenderness is typically localized due to mass effect on surrounding breast parenchyma.
However, because history and physical examination alone are insufficient to exclude breast cancer, imaging is required. Breast ultrasound is the first-line imaging modality in women age <30, and it can help assess the risk of cancer based on the composition and characteristics of the mass. Complex-appearing masses (eg, thick-walled, septated, solid and cystic components) are suspicious for cancer and automatically require core needle biopsy. In contrast, simple breast cysts appear thin-walled, anechoic (ie, fluid-filled), and without echogenic debris or solid components.
Although asymptomatic simple cysts may be observed, symptomatic patients can undergo fine-needle aspiration for pain relief. Further management then depends on aspiration results:
(Choices B and C) Diagnostic mammography is not recommended in women age <30 because this population typically has dense breast tissue that impedes visualization. MRI of the breasts can assess for tumor recurrence in patients diagnosed with breast cancer; however, it is not used to evaluate a new breast mass due to low specificity (ie, both benign and malignant masses appear enhanced).
(Choice E) Fluid culture may be indicated for turbid or purulent fluid aspirated from patients with a breast abscess (eg, fever, malaise, erythema). Cytology is typically not indicated because it has poor sensitivity and specificity for malignancy.
Educational objective:
Simple breast cysts are a common cause of palpable breast masses in women age 30-50; they are typically mobile and well-circumscribed. Fine-needle aspiration can be performed for symptomatic (ie, painful) breast cysts. Patients with nonbloody fluid on aspiration and complete resolution of both the mass and symptoms require no additional management.