Intracystic carcinoma of the breast: A case report.

A 65-year-old woman noted a lump in her left breast, although fine needle aspiration cytology showed no carcinoma cells in the serous yellow fluid of the lump. Excisional biopsy revealed intracystic papillary carcinoma with a small invasion to the stroma in the cyst wall. Breast conserving surgery with irradiation to the residual breast tissue was performed. Intracystic carcinoma of the breast is a rare form of breast disease. An oval-shaped shadow with a partially irregular margin in the mammogram and cystic mass with an irregular inner wall in the echogram suggest a higher probability of this disease. Excisional biopsy is required for a pathological diagnosis prior to an appropriate treatment. Due to the generally favorable prognosis and unlikely chance of metastasis, breast conserving surgery is the proper treatment for the disease.