Paget disease of the breast

Disease Description (Causes and Symptoms)

• Definition summary: A type of carcinoma in situ occurring in the nipple and areola, a malignant lesion in which characteristic Paget cells are observed. In many cases, it is accompanied by ductal carcinoma within the breast (ductal carcinoma in situ or invasive ductal carcinoma).
• Pathophysiology (summary): Cancer cells (Paget cells) infiltrate the epidermis of the nipple and are usually associated with ductal carcinoma in situ (DCIS) or invasive ductal carcinoma. It is explained as an underlying tumor within the breast spreading to the nipple area and causing clinical symptoms.
• Causes (summary): The exact cause is unknown. Family history (increased risk according to some reports), older age (mainly after menopause, commonly in the 60s–70s), and other factors have been reported as relevant.
• Main symptoms:
  • Itching, burning, erythema, or patches of the nipple and areola
  • Skin changes that appear scaly or eczema-like
  • Nipple discharge (which may be bloody), bleeding, or ulcer formation
  • A palpable mass within the breast is present in approximately 60% of cases (varies among reports)
  • Destruction of the nipple structure as the lesion progresses

Treatment Methods

• Basic principle after diagnosis is confirmed: Treatment is determined according to whether a concurrent lesion in the breast (DCIS or invasive cancer) is present and its extent.
• Surgical treatment:
  • Breast-conserving surgery (central excision — local excision including the nipple and areola) + radiation therapy: Considered when there is no mass on mammography or clinical examination and the lesion is localized.
  • Modified radical mastectomy (surgical removal + axillary lymph node examination/dissection): Recommended when there is a palpable breast mass, invasive cancer is confirmed on imaging, or the lesion is multifocal or extensive.
  • Axillary lymph node evaluation during surgery: If invasive findings are suspected, sentinel lymph node evaluation (sentinel lymph node biopsy or axillary dissection) is recommended as standard.
• Radiation therapy:
  • Adjuvant radiation therapy is standard after breast-conserving surgery.
  • Depending on the case, it may be used instead of or as an adjunct to surgery (depending on the case, stage, and patient’s condition).
• Systemic treatment:
  • According to standard breast cancer principles, hormone therapy, targeted therapy, and chemotherapy are applied based on hormone receptor and HER2 status.
• Lifestyle management and precautions:
  • Maintain local skin hygiene (consult a doctor when using irritating ointments or topical agents).
  • Prevent skin infection or secondary injury.
  • After treatment, manage changes in breast appearance and wounds, and undergo rehabilitation (including education on lymphedema prevention).
• Risk of complications:
  • Lymph node metastasis, local recurrence, tissue defects and cosmetic changes resulting from surgery or radiation, and treatment-related systemic side effects.

Outpatient Visit Checklist (Including Preparation Items and Example Questions)

• Items to bring (recommended):
  • A list of currently taken medications (prescription drugs, OTC drugs, and supplements)
  • Past medical history (especially breast cancer, breast surgery, radiation therapy, and hormone therapy) and family history (such as breast cancer and ovarian cancer)
  • Copies or reports of recent breast examination results (mammography, ultrasound, MRI, etc.)
  • The time symptoms began and their progression (it is useful to record changes in the lesion with photographs)
• Information to prepare in advance for the doctor during the outpatient visit:
  • When symptoms began and how they have changed (itching, discharge, bleeding, and whether a lump is present)
  • Menstrual and obstetric history (including age and menopausal status)
• Example questions (items to check for yourself before the outpatient visit):
  • Have you recently had a mammogram or ultrasound? What were the results?
  • Have you recorded the color of the nipple discharge (including whether it was bloody)?
  • Did symptoms (itching, pain, eczema, etc.) improve with the use of a particular medication (ointment)?

Examples of General Questions to Ask the Doctor

• "In my case, is a biopsy necessary even though no lesion inside the breast is visible on imaging?"
• "What surgical options should I consider, and what are the advantages and disadvantages of each (risk of recurrence and possibility of preserving the breast)?"
• "If necessary, will I undergo lymph node dissection or sentinel lymph node biopsy? How significant is the risk of complications from these procedures?"
• "If invasive cancer is confirmed, what additional chemotherapy or hormone therapy would you recommend?"
• "Is breast reconstruction (reconstructive breast surgery) possible after surgery? What are the timing and methods?"

Examples of Disease-Specific Questions

• "For my lesion, should I undergo additional breast MRI to better detect a hidden lesion (underlying carcinoma)?"
• "How do the prognosis and treatment differ when the biopsy results show accompanying ductal carcinoma in situ (DCIS) only versus accompanying invasive cancer?"

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Reference Summary (Clinical Key Points)

• Persistent skin changes of the nipple and areola (itching, scaling, discharge, or ulceration) are signs that may suggest Paget disease and must be confirmed with a full-thickness biopsy.
• In many cases, it is accompanied by DCIS or invasive ductal carcinoma within the breast. After accurately evaluating the extent of the lesion through imaging and biopsy, breast-conserving surgery or mastectomy, radiation, and systemic treatment are determined accordingly.
• Prognosis is determined by the stage of the underlying accompanying breast cancer (whether it is invasive, lymph node metastasis, and so on).