Abstract Diabetic mastopathy represents an uncommon tumor-like proliferation of fibrous tissue of the breast that usually occurs in patients who suffered from type 1 diabetes mellitus for a long time. We report an uncommon case of diabetic mastopathy presenting in a type 2 non-insulin dependent diabetes mellitus 61-year-old postmenopausal woman. Physical examination revealed a hard, low movable mass in the upper outer quadrant of the right breast. Mammography and ultrasonography showed typical features of breast cancer. Ultrasound-guided fine-needle aspiration cytology (US-FNAC) was performed showing inflammatory infiltrate, suggesting excisional biopsy. Histological findings demonstrated typical diabetic mastopathy with fibrosis, histiocytic and limphocytic infiltration without evidence of malignancy.