What are the differential diagnoses and management options for a 53-year-old perimenopausal or postmenopausal woman with nipple retraction, a pustule-like structure, and a history of cyclical breast pain?

Differential Diagnoses for Nipple Retraction with Pustule-Like Structure

The combination of nipple retraction and a pustule-like structure in a perimenopausal/postmenopausal woman requires urgent evaluation to exclude inflammatory breast cancer or Paget's disease, while also considering periductal mastitis and breast abscess as important benign differentials. 1

Critical Red Flag Diagnoses to Exclude First

Inflammatory Breast Cancer

• Any diagnosis of mastitis in a non-lactating patient should be viewed with suspicion, as inflammatory breast cancer must always be considered. 1
• Advanced cancers may present with breast pain as the only symptom, especially invasive lobular carcinoma and anaplastic carcinoma, which are disproportionately associated with mastalgia. 2
• The risk of cancer in women presenting with breast pain ranges from 1.2-6.7%, though this increases significantly when accompanied by nipple changes or skin findings. 3, 4

Paget's Disease of the Nipple

• Presents with nipple retraction, eczematous changes, or pustule-like crusting of the nipple-areolar complex. 5
• Requires biopsy for definitive diagnosis when nipple skin changes are present. 5

Benign Inflammatory Conditions

Periductal Mastitis (Duct Ectasia)

• Noncyclical mastalgia is usually unilateral, more focal, often located in the subareolar area, and is predominantly inflammatory rather than hormonal in nature. 3
• Commonly associated with smoking and presents with burning pain behind the nipple. 3, 4
• Can cause nipple retraction due to chronic inflammation and fibrosis. 1
• The pustule-like structure may represent periductal inflammation or abscess formation. 1

Breast Abscess

• Failure to respond to appropriate antibiotic therapy for presumed mastitis should suggest abscess formation, requiring prompt intervention. 1
• More common in lactating women but can occur in non-lactating patients with periductal inflammation. 1

Immediate Diagnostic Approach

Clinical Evaluation

• Document whether pain is cyclical (70% of cases) versus noncyclical (25% of cases), as noncyclical pain with focal findings is more concerning. 3
• Perform clinical breast exam specifically looking for palpable mass, asymmetric thickening, nipple discharge, or skin changes beyond the pustule. 4
• Assess for reproducible chest wall tenderness to exclude costochondritis as extramammary cause. 6

Imaging Protocol

• For women ≥30 years with focal findings like nipple retraction and pustule, obtain diagnostic mammogram with ultrasound immediately. 3, 4
• Ultrasound is more sensitive than mammography for detecting abscesses and inflammatory changes. 7
• Do not delay imaging based on age in this clinical scenario—the combination of nipple retraction and pustule warrants immediate evaluation regardless of screening status. 4

Tissue Diagnosis

• Any suspicious findings on examination or imaging require biopsy—options include fine-needle aspiration, core needle biopsy, or excisional biopsy. 5
• If the pustule-like structure has purulent drainage, send for culture and sensitivity. 1
• Nipple skin changes require punch biopsy to exclude Paget's disease. 5

Management Algorithm Based on Findings

If Imaging Shows Abscess or Inflammatory Changes

• Initiate broad-spectrum antibiotics covering skin flora. 1
• Arrange surgical consultation for drainage if abscess is confirmed. 1
• Close follow-up is essential—failure to respond to appropriate therapy within 48-72 hours mandates reassessment for inflammatory breast cancer. 1

If Imaging and Biopsy Are Benign

• For smokers with periductal inflammation and burning pain behind the nipple, smoking cessation should be advised as primary intervention. 3, 4
• Over-the-counter NSAIDs can provide symptomatic relief for inflammatory pain. 3
• Reassurance is often sufficient once malignancy is excluded, as noncyclical mastalgia has spontaneous resolution in up to 50% of patients. 6

Critical Pitfalls to Avoid

• Never dismiss nipple retraction with skin changes as simple mastitis without tissue diagnosis—inflammatory breast cancer can mimic infection. 1
• Do not attribute all breast symptoms to benign mastalgia when structural nipple changes are present. 2
• Avoid ordering only screening mammography when focal findings exist—diagnostic mammogram with ultrasound is required. 4
• Do not fail to obtain tissue diagnosis when imaging shows suspicious features or clinical findings persist despite treatment. 5