What diagnostic tests are recommended for suspected Paget's (Paget's disease of the breast) breast cancer?

Diagnostic Testing for Paget's Disease of the Breast

For suspected Paget's disease of the breast, diagnostic evaluation should include bilateral diagnostic mammography with or without ultrasound, followed by full-thickness surgical biopsy of the nipple-areolar complex, and breast MRI to define the extent of disease and identify additional lesions. 1

Initial Evaluation

• Complete history and physical examination with careful assessment of the nipple-areolar complex, looking for eczema, bleeding, ulceration, and itching of the nipple 1
• Bilateral diagnostic mammography with or without ultrasound as the first imaging study, regardless of patient age 1
• Be aware that pure Paget's disease can be occult on mammography, and a negative mammogram does not exclude the diagnosis 1

Biopsy Approach

• Full-thickness surgical biopsy of the nipple-areolar complex that includes the epidermis and at least a portion of any clinically involved nipple-areolar complex 1
• Punch biopsy of the skin or nipple should be performed if imaging findings are consistent with BI-RADS category 1-3 (negative, benign, or probably benign) 1
• Core needle biopsy (preferred) with or without punch biopsy if imaging findings are consistent with BI-RADS category 4-5 (suspicious or highly suggestive of malignancy) 1

Advanced Imaging

• Breast MRI is strongly recommended when biopsy confirms Paget's disease to define the extent of disease and identify additional disease 1, 2
• MRI can detect underlying ductal carcinoma in situ (DCIS) or invasive cancer that may be occult on mammography 2, 3, 4
• MRI findings typically show abnormal nipple enhancement with an ill-defined thickened nipple-areolar complex in patients with underlying DCIS 2

Rationale for Comprehensive Evaluation

• Up to 80-90% of Paget's disease cases have associated cancer elsewhere in the breast, which may be either DCIS or invasive cancer 1, 5
• The associated cancers are not necessarily located adjacent to the nipple-areolar complex 1
• Mammography alone fails to identify underlying disease in up to 50% of cases, particularly when there is no palpable mass 4, 5
• Multifocal disease is common (73% of cases), making thorough evaluation essential for treatment planning 5

Clinical Pitfalls to Avoid

• Do not mistake Paget's disease for benign conditions like eczema or dermatitis; if in doubt, perform a biopsy 1, 6
• If clinically suspicious for Paget's disease but low suspicion for eczema, a short trial of topical steroids may be considered, but should not delay diagnostic evaluation 1
• A benign skin biopsy result should prompt reassessment of clinical and pathologic correlation, consideration of breast MRI, repeat biopsy, and consultation with a breast specialist 1
• Never rely solely on mammography for evaluation, as it may be negative in up to 50% of Paget's disease cases 4

By following this diagnostic algorithm, clinicians can ensure accurate diagnosis of Paget's disease and appropriate evaluation for associated breast malignancies, which is critical for proper treatment planning and improved outcomes.