OVERVIEW

What is breast Paget's disease?

Breast Paget's disease (Paget disease of the breast, PDB), also known as nipple Paget's disease, is a malignant tumor that can invade the nipple surface/epidermis, leading to inflammatory-like changes in the nipple. Clinically, it often manifests as skin changes involving the nipple, typically presenting as eczema-like alterations.

Is breast Paget's disease common?

It is rare, progresses slowly, and has a low degree of malignancy.

What are the types of breast Paget's disease?

Breast Paget's disease was first described by James Paget in 1874, hence its name. It is often associated with breast ductal carcinoma and clinically manifests in three forms: nipple erosion type, mass type, and nipple erosion + mass type.

SYMPTOMS

What are the symptoms and manifestations of mammary Paget's disease?

• Mammary Paget's disease is characterized by scaly, inflammatory, vesicular, or ulcerative lesions that begin on the nipple and later spread to the areola. Occasionally, bloody discharge may also occur.

• The disease usually affects one side, but some patients may have bilateral involvement.

• Nipple retraction is rare but may occur in advanced stages.

• Pain, burning sensation, and/or itching are often present, and these symptoms may appear before obvious clinical lesions. Once they occur, close follow-up monitoring is necessary.

How does mammary Paget's disease typically progress?

• It usually starts unilaterally, with initial symptoms such as nipple itching and burning, followed by redness of the breast skin, which patients often overlook.

• As the disease progresses, the skin becomes rough and thickened, with symptoms like scaling, erosion, exudation, and ulceration. Temporary healing under scabs may occur after dermatological treatment, but recurrence is common, exposing granulation tissue. The lesions spread from the nipple to the areola or nearby skin, and in severe cases, the nipple contour may disappear.

• In later stages, a lump may be palpable under the areola, and nipple inversion or axillary lymph node enlargement/metastasis may occur. It is often associated with ductal carcinoma or other invasive cancers.

CAUSES

What is the cause of mammary Paget's disease?

The etiology of mammary Paget's disease remains unclear, with two main theories:

• Paget cells originate from ductal carcinoma cells that migrate along the basement membrane of the lactiferous ducts toward the nipple epidermis.

• Paget cells arise from the in situ malignant transformation of pluripotent stem cells in the lactiferous ducts and epidermal basal layer.

DIAGNOSIS

What tests do patients with mammary Paget's disease need to undergo? Why are these tests necessary?

• Pathological examination: Cytological examination is simple, convenient, and highly diagnostic, enabling the detection of early-stage patients.

• Mammography: The mammographic presentation of mammary Paget's disease resembles that of ductal breast cancer. Although not distinctive, it can directly reveal the lesion's location and extent, providing crucial guidance for surgical approach selection and postoperative treatment planning.

• Ultrasound: It can identify masses within the breast parenchyma, which is particularly significant for cases with concurrent breast lumps.

• Magnetic Resonance Imaging (MRI): Recent studies have demonstrated that MRI is highly useful in detecting occult breast cancer.

How is mammary Paget's disease diagnosed?

The diagnosis of mammary Paget's disease is primarily confirmed through pathological examination, while clinical manifestations and imaging studies can aid in clarifying the diagnosis.

What conditions should mammary Paget's disease be differentiated from?

This disease is often misdiagnosed as nipple eczema, dermatitis, or superficial melanoma, leading to delayed treatment.

• Breast eczema typically presents as bilateral, symmetrical clusters of vesicles, erosions, or crusts with indistinct borders and lymphocyte infiltration, lacking cancerous infiltration or metastasis. It can be cured with eczema treatment within 15–20 days. In contrast, mammary Paget's disease is usually unilateral, persists despite eczema treatment, or recurs after healing.

• Many Paget's cells contain prominent melanin, making them easily mistaken for superficial melanoma. Histologically, melanoma melanocytes infiltrate directly from the dermoepidermal junction into the papillary dermis, whereas malignant cells in mammary Paget's disease are diffusely distributed in the superficial basal layer of the epidermis. Definitive diagnosis relies on immunohistochemistry.

TREATMENT

How is mammary Paget's disease treated?

The treatment of mammary Paget's disease includes the following aspects:

• Paget's disease without a mass: For cases without a palpable mass or imaging abnormalities, standard treatment includes mastectomy or breast-conserving therapy (excision of the nipple-areolar complex followed by whole-breast radiotherapy).

• Paget's disease with a mass: For cases with a palpable mass or imaging abnormalities, there is a higher likelihood of concurrent invasive carcinoma, multicentric lesions, and lymph node metastasis. Moreover, Paget's disease with invasive carcinoma is more aggressive than typical mass-type breast cancer. Therefore, radical or modified radical mastectomy should be performed, similar to general breast cancer treatment.

• Adjuvant therapy: Based on pathological results, concurrent breast cancer, and axillary lymph node metastasis, radiotherapy, chemotherapy, endocrine therapy, and biological therapy should be selected following the treatment principles for general breast cancer.

Do patients with mammary Paget's disease need hospitalization?

Usually, yes.

What is the prognosis for patients with mammary Paget's disease? Can it be cured?

The prognosis of PDB depends on the presence of deep invasive ductal carcinoma or axillary lymph node metastasis. The prognostic significance of tumor stage outweighs that of Paget's disease. Compared to PDB without a palpable mass, PDB with a palpable mass tends to have a higher stage and thus a lower 5-year survival rate.

• Generally, the 5-year survival rates for women with PDB with and without a palpable mass are 20%–60% and 75%–100%, respectively.

• When a palpable mass and invasive ductal carcinoma are present, the 5-year cause-specific survival rate is 37%–43%, whereas in cases with only occult ductal carcinoma in situ and no mass, this rate is 90%–100%.

Which department should patients with mammary Paget's disease visit?

Patients should visit the breast surgery or thyroid/breast surgery department. If the hospital does not have specialized departments, they may consult the general surgery department.

DIET & LIFESTYLE

What are the precautions after surgical treatment for breast Paget's disease?

• Strictly monitor vital signs, maintain patency of all tubes, observe drainage fluid, and be alert for any signs of bleeding.

• Monitor the condition of the skin at the surgical site, check for subcutaneous fluid accumulation or lymphedema.

• Postoperative functional recovery exercises should be emphasized.

What complications are prone to occur after breast Paget's disease surgery? How to care for them?

• Skin flap necrosis: Apply light pressure dressing postoperatively to ensure even compression across all areas of the flap, avoiding excessive tightness of the chest bandage to prevent necrosis. Closely observe the color, temperature, and swelling of the skin around the incision.

• Subcutaneous fluid accumulation: Maintain continuous negative pressure drainage postoperatively, promptly clear drainage fluid, ensure tube patency, and guide patients and their families in maintaining drainage tube effectiveness.

• Lymphedema: Elevate the affected limb to promote lymphatic drainage. Under nursing guidance, perform massage therapy and appropriate exercises to aid recovery.

Does breast Paget's disease require follow-up examinations? How are they conducted?

Regular follow-up imaging tests such as MRI, ultrasound, and mammography are necessary. Seek medical attention promptly if abnormalities are detected.

PREVENTION

How to prevent mammary Paget's disease?

• Women should be vigilant about mammary Paget's disease, perform regular self-examinations, and seek prompt medical attention if eczema-like changes or palpable lumps appear. Standardized examinations should be conducted to confirm whether it is mammary Paget's disease.

• Maintain a regular schedule: The incidence of tumors is closely related to lifestyle. Adjusting one's lifestyle can help avoid such nightmares.

• Manage emotions: Avoid mental stress, cultivate good psychological resilience, and maintain emotional stability to enhance the body's ability to fight cancer.

• Follow a scientific diet: Pay attention to a balanced diet and adopt healthy eating habits.