Pathological Nipple Discharge
A 32-year-old woman has two months of left breast discomfort with spontaneous blood stained discharge from a single duct. She is not pregnant and takes no medication. Examination of both breasts and axillae shows no palpable mass, no skin change, and no lymphadenopathy. Which of the following is the most appropriate initial breast investigation?
- A.Computed tomography of the chest and breasts
- B.Targeted breast and retroareolar ultrasoundCorrect
- C.Bilateral screening mammography
- D.Contrast enhanced breast magnetic resonance imaging
Explanation
Spontaneous, unilateral, single-duct bloody nipple discharge is pathological and always requires investigation, even when examination is normal. The commonest cause in a young woman is an intraductal papilloma, a benign wart-like proliferation within a duct, but duct ectasia and, less often, ductal carcinoma in situ or invasive carcinoma must be excluded. The choice of first imaging test is driven by age. At 32 years the breast is usually dense, and because both fibroglandular tissue and tumors appear white on a mammogram, dense tissue masks small lesions and lowers sensitivity. Ultrasound uses no ionizing radiation, performs well in dense breasts, and is the best modality for inspecting the retroareolar ducts, where it can show ductal dilatation and an intraductal filling lesion. It also guides sampling if a target is found. For these reasons targeted ultrasound is the appropriate initial investigation, with mammography added as part of the complete workup, particularly in women aged 40 years and above. Magnetic resonance imaging is a problem-solving and high-risk screening tool used when mammography and ultrasound are inconclusive, not a first-line study. Computed tomography has no role in primary breast imaging because it resolves breast detail poorly and delivers a significant radiation dose, and it is used only for staging established cancer.
Why each option
- A.
- Computed tomography gives poor breast soft tissue detail and a high radiation dose, and it is used only to stage confirmed malignancy.
- B.
- Correct. Ultrasound is radiation free, effective in dense breasts, and best at visualizing the retroareolar ducts and intraductal lesions in a woman of 32 years.
- C.
- Mammography is part of the wider workup but is less sensitive as the first test in a young woman with dense breast tissue.
- D.
- Magnetic resonance imaging is reserved for inconclusive conventional imaging or high-risk screening and is not the initial test for nipple discharge.
Reference: ACR Appropriateness Criteria, Evaluation of Nipple Discharge, 2022
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