POLYHEDRAL MICROCALCIFICATIONS AT MAMMOGRAPHY - HISTOLOGIC CORRELATION WITH CALCIUM-OXALATE

Pathologists have associated calcium oxalate dihydrate (weddellite) in breast biopsy specimens with benign or borderline lesions and rarely with malignancy. These microcalcifications may have a polyhedral shape in histologic specimens owing to their crystalline structure. A retrospective radiologic-histologic correlation study was performed on 300 clusters of microcalcifications to determine if microcalcifications with a polyhedral shape could be found at mammography. In 19 cases (6.3%), polyhedral microcalcifications (PMs) were detected by two radiologists. In 12 of these 19 cases, weddellite crystals were found in the histologic specimen under polarized light; in seven cases, no calcification was found. Although rare, PMs can be found at mammography by radiologists aware of their existence. They are due to weddellite crystals and in this series were associated with benign disease in 89% of cases. Prospective studies are required to determine the frequency of PMs on screening mammograms and to evaluate their negative predictive value.