To summarize the clinical features of peripheral nonlactational chronic mastitis and improve the diagnosis and treatment.

Retrospectively analysis of clinicopathological data of 35 patients diagnosed as peripheral nonlactational chronic mastitis in the past four years.

At admission 15 patients were diagnosed as breast cancer and 20 patients could not be ruled out the diagnosis of breast cancer. All patients had no fever and local reddening and swelling. There were 20 cases with breast pain and 13 cases with immunodeficiency. Patients with lactational mastitis history were younger, had higher incidence of breast pain, and lower incidence of immunodeficiency than those without. Core biopsy was done in 14 patients and 12 chronic mastitis were diagnosed. Twenty-seven patients underwent surgical treatment. Pathological diagnosis included chronic mastitis, necrotic lesion with chronic inflammation, granulomatous mastitis and plasma cell mastitis. Core biopsy was performed on 14 patients and 12 were chronic inflammation. Surgical treatments including completely resection, open drainage or tube drainage. All patients were cured after treatment.

Misdiagnosis of peripheral nonlactational chronic mastitis as breast cancer is common. Core biopsy is effective for pathological diagnosis. Chronic mastits is easy to relapse and surgical treatment is necessary. Compared with open drainage, the method of lumpectomy combined with irrigation and instillation of antibiotics can shorten course of disease.