BACKGROUND: Cystic hypersecretory carcinoma (CHC) of the breast is a rare variant of intraductal carcinoma. It is characterized by a multicystic, yellow-brown lesion with gelatinous material grossly and cystically dilated ducts with an eosinophilic secretion microscopically. The histologic or cytologic features can be deceptively bland. CASE: A 37-year-old female presented with an 8-cm-diameter, firm mass in the breast. Radical mastectomy was performed after fine needle aspiration (FNA). The moderately cellular smear had a characteristic background of proficient, intensely staining secretion with bubbling. The cellular components were various, ranging from sheets of benign hyperplastic ductal cells to three-dimensional clusters or papillae of frankly malignant ductal cells, with varying degrees of secretory activity. The background consisted of inflammatory cells, naked nuclei and foamy histiocytes. The cytologic findings correlated well with the histologic features of the tumor, which showed both micropapillary intraductal carcinoma with apocrine metaplasia and focal high grade invasive carcinoma in a background of cystic hypersecretory hyperplasia. CONCLUSION: This was the first reported case of FNA cytology of an invasive form of CHC. CHC has characteristic features on FNA, and so a reliable diagnosis can be made.