Image Quiz

Answer: Systemic Sclerosis

The x-ray shows the hands of a patient with limited systemic sclerosis – the opacities seen prominently in the first and second digits of both hands are subcutaneous calcific deposits (calcinosis cutis). Acroosteolysis (destruction of the distal phalanges) and skin atrophy over the fingertips can also be seen. The differential for calcific deposits are numerous, but the major differentials include dermatomyositis, arterio-venous malformations, parasitic infestation (e.g. cysticercosis, dracunculiasis), neoplasms (osteoma and osteosarcoma) and trauma.

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X-ray features of rheumatoid arthritis are joint space narrowing, periarticular bony erosions and bony deformities such as Boutonniere’s and swan-neck deformities of the fingers.

Gouty tophi are urate deposits commonly seen in tendons, joints and pinna. These are seen as large white soft tissue lesions that are less radio-opaque than the calcium deposits of systemic sclerosis. They may be intra- or extra-articular in location. Other findings in advanced gout include punched-out lytic lesions and “mouse bite” erosions of the bone, and overhanging margins caused by periarticular erosion.

In osteoarthritis, joint space narrowing, subarticular sclerosis, osteophytes and subchondral cysts are the typical findings on radioimaging. Osteophytes can be differentiated from calcinosis in that the former are outgrowths of bone (and therefore of similar radiodensity to bone) that occur at joint margins.

Raynaud’s disease is an idiopathic form of Raynaud’s syndrome, in which there is peripheral digital ischaemia due to vasospasm. Raynaud’s syndrome is seen commonly in systemic sclerosis (it puts the ‘R’ in ‘CREST’); however as there is an underlying cause it is referred to as Raynaud’s phenomenon rather than disease. Raynaud’s syndrome in itself does not cause significant x-ray changes in the hands.

Christina Yek, Cambridge University School of Clinical Medicine

Quiz Image:
What prominent pathology is demonstrated in the above x-ray?