Abstract: Objective To summarize the diagnosis and treatment of male breast intracystic papillary carcinoma by reporting one case of intracystic papillary carcinoma of the breast combined with colon adenocarcinoma in male,so as to improve the understanding of this rare disease. Methods Clinical data about one male patient with intracystic papillary carcinoma of breast,who had previously suffered from colon adenocarcinoma,in the breast surgery department of Guangzhou Red Cross Hospital in March 2019 were analyzed,and the diagnosis and treatment of male breast intracystic papillary carcinoma was discussed. Results The patient was diagnosed with ascending colon adenocarcinoma in April 2014,and had undergone surgery and chemotherapy.The postoperative recovery was good,and no tumor recurrence and metastasis was observed during follow-up.In March 2019,the patient was admitted for "left breast mass for 8 months".Color ultrasound and magnetic resonance imaging of the breast found a mass in the left breast,and "left breast simple resection" was performed.Postoperative pathology examination confirmed the diagnosis of intracystic papillary carcinoma in the left breast.After the operation,radiotherapy was completed and tamoxifen endocrine therapy was initiated.No recurrence or metastasis had been observed. Conclusion Breast intracystic papillary carcinoma complicated colon cancer is rare.If there is no clear evidence of infiltration,diagnosis and treatment of male breast intracystic papillary carcinoma should be conducted as carcinoma in situ.