Chondrosarcoma of the calcaneum and massive soft tissue calcification in a patient with hereditary and acquired connective tissue diseases.

We describe the first case of the coexistence of the hereditary connective tissue disorder multiple exostoses (HME) and an acquired connective tissue disorder manifest by the overlap of dermatomyositis (DM), scleroderma (PSS), high titre speckled pattern antinuclear antibodies, and increased antibodies to double stranded deoxyribonucleic acid (DNA). Furthermore this patient developed chondrosarcoma of the calcaneum (an unusual site for this malignancy) and massive soft tissue calcification (an unusual feature of PSS, adult DM, and systemic lupus erythematosus (SLE)).