Reviewers: Dharam M. Ramnani, MD
Tumoral calcinosis is formation of tumor-like calcium deposits in periarticular soft tissues of hip, elbow, and shoulder. Less commonly involved sites include hands, feet, knee, scalp, neck, and paraspinal region. It affects otherwise healthy children, adolescents, and young adults. There are no abnormalities in calcium metabolism. There are three forms of tumoral calcinosis - Sporadic (nonfamilial; idiopathic), Familial (hyperphosphatemic & normophosphatemic variants), and Secondary Tumoral Calcinosis (primary or secondary hyperparathyroidism, sarcoidosis, systemic sclerosis, and destructive bone lesions caused by metastases or infections). Grossly, it appears as an unencapsulated, firm subcutaneous mass that may extend into the adjacent muscles. The cut surface shows nodules separated by fibrous septa and filled with yellow-white chalky material with gritty consistency or milky-yellow white liquid. Microscopically, the active phase of the lesion shows a central area of calcification surrounded by macrophages, osteoclast-like multinucleated giant cells, fibroblasts, and chronic inflammatory cells. The cellularity decreases during the inactive phase, leaving behind amorphous or granular calcified material bordered by dense fibrosis. Reference: Enzinger & Weiss’s Soft Tissue Tumors, Sixth Edition, 2014; p. 947-951.