11.3 Inflammatory Breast Cancer & Paget Disease of the Nipple

Inflammatory Breast Cancer

Definition and Epidemiology

Inflammatory breast cancer (IBC) accounts for about 1% to 5% of breast cancers but a disproportionate share of deaths. It is more common in younger women, Black women, and women with obesity, and it is often HER2-positive or triple-negative. About one third of patients have distant metastases at diagnosis.

IBC is a clinical diagnosis confirmed by pathology. International consensus criteria require:

• Rapid onset of breast erythema, edema, and/or peau d'orange, with or without a palpable mass.
• Duration of 6 months or less.
• Involvement of at least one third of the breast.
• Pathologic confirmation of invasive carcinoma.

Tumor emboli in dermal lymphatics support the diagnosis but are not required, and finding them without the clinical picture does not make a tumor IBC. The AJCC category is T4d, so IBC is at least stage IIIB.

Mimics: When "Mastitis" Is Not Mastitis

The breast is red, warm, heavy, and swollen, often without a lump, so IBC is frequently misdiagnosed as mastitis or cellulitis. Red flags: a nonlactating woman, no fever or modest systemic symptoms, peau d'orange, rapid enlargement, nipple flattening, or no improvement after 7 to 14 days of antibiotics. Any presumed infection that does not resolve with one course of antibiotics needs imaging and biopsy.

Workup

• Bilateral diagnostic mammography and ultrasound of the breast and regional nodes; breast MRI is often added.
• Core biopsy of the breast mass or abnormal tissue, and a skin punch biopsy.
• ER, PR, and HER2.
• Systemic staging with contrast CT of chest, abdomen, and pelvis plus bone scan, or FDG PET/CT.
• Genetic counseling and fertility discussion.

Trimodality Treatment

1. Neoadjuvant systemic therapy: anthracycline- and taxane-based chemotherapy, with trastuzumab and pertuzumab for HER2-positive disease; pathway-specific agents follow tumor biology.
2. Modified radical mastectomy: total mastectomy with level I and II axillary dissection. Sentinel node biopsy is not reliable because dermal lymphatics are obstructed. Skin-sparing and nipple-sparing mastectomy are not used because the skin is involved. Reconstruction is usually delayed until after radiation.
3. Post-mastectomy radiation to the chest wall and regional nodes, including supraclavicular and internal mammary nodes as indicated.
4. Adjuvant therapy by subtype: endocrine therapy, completion of HER2 therapy, or capecitabine or other escalation for residual disease.

Breast-conserving surgery is contraindicated. Even with aggressive therapy, long-term survival is lower than for other stage III cancers, so psychosocial support and clear communication matter.

Nursing Priorities in IBC

• Expedite referral: IBC can progress over weeks.
• Photograph and measure erythema to track response.
• Prepare patients for an intense, lengthy plan and for mastectomy without immediate reconstruction.
• Monitor lymphedema risk after axillary dissection and nodal radiation.
• Connect patients with IBC-specific support resources.

Paget Disease of the Nipple

Presentation

Paget disease accounts for about 1% to 4% of breast cancers. Malignant Paget cells infiltrate the epidermis of the nipple, causing:

• Unilateral scaling, crusting, redness, oozing, or erosion that begins on the nipple and may spread to the areola.
• Itching, burning, or bleeding.
• In advanced cases, nipple destruction.

Most patients (well over 80% in most series) have an underlying DCIS or invasive carcinoma, which may be palpable or visible on imaging, or may be found only with MRI.

Paget Disease Versus Eczema

Any unilateral nipple rash that does not resolve after a short trial of topical steroids needs biopsy.

Workup and Treatment

• Full-thickness wedge or punch biopsy of the nipple skin; Paget cells are usually CK7-positive and often HER2-positive.
• Bilateral diagnostic mammography and ultrasound; breast MRI when these are negative, to find an occult underlying cancer.
• Surgery: central lumpectomy removing the nipple-areolar complex followed by whole-breast radiation is appropriate when disease is limited to the central breast and margins can be cleared. Mastectomy is chosen for extensive or multicentric disease.
• Axillary staging: sentinel node biopsy when invasive cancer is present or when mastectomy is performed.
• Paget disease without underlying cancer is staged Tis (Paget); otherwise the underlying tumor determines stage.
• Adjuvant therapy follows the underlying tumor's biology.

Nursing Priorities in Paget Disease

Validate that a delayed diagnosis after months of "eczema" treatment is common and frustrating. Discuss nipple loss and later nipple reconstruction or 3D tattooing, and teach wound care after central lumpectomy.

Primary Inflammatory Cancer Versus Neglected Locally Advanced Cancer

Not every red, swollen breast with cancer is inflammatory breast cancer. A long-standing, neglected locally advanced tumor can ulcerate or cause secondary skin redness and edema over the mass (usually classified T4b). Primary IBC is defined by its rapid onset within 6 months and diffuse involvement, often without a dominant mass. The distinction matters because IBC carries a worse prognosis and requires trimodality therapy and full staging.

Survivorship After IBC

Survivors of IBC face a higher risk of recurrence than other stage III survivors, and many have had axillary dissection and nodal radiation, so lymphedema surveillance is essential. Body image concerns are common because reconstruction is delayed and the chest wall receives high-dose radiation. Surveillance follows standard schedules without routine scans, and clinical trials are encouraged at every stage.