Breast Hamartoma: Mammographic Findings

Breast hamartoma is an uncommon, benign, slow-growing lesion found in all age groups after puberty. This pathological entity has a reported incidence of 1.2% of benign lesions and 4-8% of benign breast tumors in women (1, 2). It appears that with the increasing use of breast screening more hamartomas are likely to be identified. This rare pathological entity consists of a well-circum-scribed, benign tumor, composed of variable amounts of fat, fibrous and glandular tissue that may contain various benign changes such as fibrocystic changes. Breast hamartomas usually present as painless mobile breast lumps in middle-aged women. Up to 60% of these benign breast lesions are soft and non-palpable (2). The various amount of fat and fibrous tissue within the breast hamartomas results in different mammographic appearances. The characteristic mammographic features of hamartoma are that of a nonhomogeneous compress-ible mass with dense nodules of fibrous connective tissue interchanged by a thin radioopaque pseudocapsule. The pseudocapsule results from displacement of breast pa-renchyma by the tumor (3, 4). Hamartomas that contain predominantly fibrous tissue appear uniformly dense. In these patients, hamartomas can not be differentiated from fibroadenomas that generally have glandular homogeneous density within a thin halo of compressed fat. Hamartomas containing predominantly fatty tissue may mimic lipoma, fat necrosis and oil cyst (4, 5). Lobulated densities that may be dispersed within the encapsulated fat, described as a " slice of salami " (3, 5). Calcification is a rare mammographic finding, but amorphous or smooth and round microcalcifications are reported. It is important to keep in mind that pleomorphic calcification, spiculated opacity or a well-demarcated dense opacity in a hamartoma are suspicious for malig-nancy (6, 7). Twenty-five patients with breast hamartomas were diagnosed based on mammography and pathologic findings during a ten-year period from July 1998 to July 2008. The patients' age ranged from 28 to 60 years. Nine of the cases had non-palpable lesions as a result of their small size or consistency that was similar to that of the surrounding breast tissue. These cases were selected from the group of patients with lesions detected in the screening program. Clinically, 16 lesions were palpable masses which were well-defined and of soft consistency. All patients underwent preoperative mammography. The most