Eczematoid carcinoma of breast is a special type of breast cancer, first described by Sip Paget in 1874, hence the name extramammary Paget’s disease. It is characterized by chronic eczema-like changes in the nipple and areola area, so it is also called epithelioma-like eczema. Tests: Laboratory tests: Nipple discharge examination and fine needle aspiration cytology of breast masses are useful for diagnosis. Other ancillary tests: Eczema-like carcinoma of the breast should be ruled out as a complication of ductal carcinoma of the breast, and mammography, dry plate photography and infrared examination should be done. If there is a combination of Paget’s disease in the anal area, anal fingering, anoscopy and appendiceal examination should be done at the same time. Diagnosis: The onset of eczema-like changes in the unilateral breast or in areas with more sweat glands (e.g., axillae), with a hardened basal infiltrate, clear boundaries, and a chronic course, should raise the alarm and raise suspicion of the disease. The diagnosis can be confirmed by finding Paget cells on pathological tissue biopsy. Differential diagnosis: Clinical differentiation should be made between chronic breast eczema, contact dermatitis, Bowen’s disease, melanoma and other diseases. Breast eczema and contact dermatitis are most often seen in young people, with bilateral onset, soft to touch, not hard at the edges, rarely with loss of nipple contour, and no breast masses, and have a better outcome for treatment. Treatment: Surgical procedures are the treatment of choice for this disease. Surgical treatment The extent of surgical excision should be determined by whether a lump can be palpated in the mammary gland. If the lesion is confined to the nipple, and there is no lump in the breast and the axillary lymph nodes are not large, total mastectomy is feasible; if the axillary lymph nodes are large and cancer metastasis is suspected, modified radical surgery should be performed; if there is a lump in the breast, radical surgery or extended radical surgery should be performed. Radiation therapy If patients cannot tolerate surgery for various reasons, X-ray radiation therapy can be used. However, the efficacy is poor. Since eczematous carcinoma of the breast may originate from the sweat gland, deeper X-ray treatment (tissue half-valent layer 8-10mm) should be used. The amount of irradiation is 599 rad for one time for small area damage; 200-300 rad for one time for large area damage, 1 time/d, total 5000-8000 rad. Prognosis: The survival rate of this disease is higher than general breast cancer, and the main factors affecting the prognosis are whether there is a lump in the breast and whether there is metastasis in the lymph nodes. nance reported that the 5-year survival rate is 94.1% for 53 cases without lump in the breast; Kister reported that 133 out of 159 cases were radical resections and the 10-year survival rate was 79% for those without axillary lymph node metastasis and only 28% for those with lymph node metastasis. In conclusion, the prognosis of this disease is good for those with simple nipple lesions, poor for those with intra-mammary masses, and even worse for those with metastases in the lymph nodes.