Heterotopic ossification in systemic sclerosis.

Although myopathy or myositis may occur in systemic sclerosis (SSc) as well as soft tissue calcification, ossification is not a feature of the disease. Here we present an unusual case of extended calcification and, to a lesser degree, ossification of the right gluteal region, lateral thigh, and knee, with associated myopathy and functional impairment. Heterotopic ossification (HO), or myositis ossificans, has not been reported so far in scleroderma patients, making this case, in our opinion, unique and interesting. However, differential diagnosis from other causes of extraskeletal ossification, such as tumours or tumour-like conditions, is required.