Tumoral calcinosis: a case report with an electron microscopic study.

A 68-year-old woman developed large subcutaneous masses on her abdomen and thighs after a bruise sustained in a traffic accident. She had severe pain when sitting up straight. Histological examination revealed calcified tissues in the entire dermis of the injured areas. On electron microscopy, crystalline materials were observed in the dermis, which seemed to be formed by the deposition of hydroxyapatite on unusual proteoglycan. In a vessel wall, a thick, layered basement membrane was observed. This suggests that vascular injury and subsequent hypoxia play a role in the process of calcinosis. We performed a partial resection with good results in alleviating the patient's pain.