Fibroadenomatoid hyperplasia: a cause of suspicious microcalcification on mammographic screening

Fibroadenomatoid hyperplasia is a well-described but rare benign breast lesion with composite features of fibroadenoma and fibrocystic change. Because fibroadenomatoid hyperplasia has not to our knowledge been reported as a cause of suspicious microcalcifications and because several pathology reports of biopsies of mammographically detected microcalcification at our institution included fibroadenomatoid hyperplasia, we undertook this study to describe the features of mammographically detected microcalcification seen in patients with fibroadenomatoid hyperplasia.

Two breast pathologists reviewed the records of 54 mammographically detected lesions that were compatible with a diagnosis of fibroadenomatoid hyperplasia and that provoked subsequent core biopsy or surgical excision of microcalcifications. Eleven cases (20%) fulfilled the diagnostic criteria for fibroadenomatoid hyperplasia. The sites of all calcifications found at histology were documented, and the mammographic features were described.

Eleven cases of fibroadenomatoid hyperplasia were identified in nine core biopsy samples and two surgical specimens. Calcification was present in all 11 pathologic specimens. Calcification was stromal in nine, subepithelial in two, and epithelial in none. The mammographic features of fibroadenomatoid hyperplasia in all 11 cases were granular microcalcifications that varied in shape, size, and density and had no associated mass; of these calcifications, 91% were in a localized, irregularly shaped cluster. Rod-shaped calcifications were also seen in 64% of cases.

Fibroadenomatoid hyperplasia is a cause of suspicious, granular, clustered microcalcifications on screening mammography. Fibroadenomatoid hyperplasia can be confirmed using 14-gauge core biopsy in most cases.