(Image #1 and Image #2)

(Image #3 and Image #4)

Findings: Image #1 is a plain film of the hand demonstrating acroosteolysis of the distal tufts of the bilateral fourth and fifth distal phalanges.

Image #2 is a plain film of the hands in a second patient with the same diagnosis demonstrating acroosteolysis as well as flexion contractures.

Image #3 is a PA chest x-ray demonstrating mild basilar interstitial prominence as well as calcifications projecting over the left shoulder soft tissues.

Image #4 is a plain film of the pelvis demonstrating extensive soft tissue calcifications.

Diagnosis: Systemic sclerosis (scleroderma).

Discussion: Progressive systemic sclerosis (scleroderma) is a disorder of connective tissue dysfunction which affects whole organ systems including skin, lungs, GI, heart, kidneys and musculoskeletal. The characteristic radiographic presentation is generally defined as soft tissue atrophy, calcifications, and distal phalangeal resorption in the hand. In addition, recently described findings include erosion involving the distal interphalangeal disease (DIP) and less commonly proximal interphalangeal (PIP) joints.

Although there has been no definite pathogenesis identified, it is felt that progressive systemic sclerosis secondary to a structural defect in the microvasculature. This is supported by the fact that there are often vascular changes identified in multiple tissues.

Systemic sclerosis affects women approximately three to four times more commonly than it does men, with the onset between the third and fifth decades being most common. Raynaud's phenomenon is a characteristic finding in these patients consisting of sudden pallor of the digits with associated pain when exposed to cold. In addition, patients often complain of joint pain, erythema, and swelling. Skin involvement is the most characteristic clinical finding in systemic sclerosis consisting of bouts of edema, thickening of the dermis, and progressive rigidity with fixation to the subcutaneous tissues. A small percentage of patients will progress to develop significant atrophy of the skin as well as muscle and subcutaneous tissues.

Tissue abnormalities in the hand and wrist are felt to be the most characteristic radiographic abnormalities found in systemic sclerosis. These are findings such as subcutaneous calcifications, soft tissue resorption, and osseous destruction. In addition, flexion contractures of the hands develop secondary to abnormal tightening of the skin. The radiographically identifiable calcifications often involve the subcutaneous tissues, joint capsules, and/or synovial lining. Osseous resorption is a characteristic finding in patients with systemic sclerosis and has been seen in as many as 80% of these patients. The resorption initially involve the palmar aspect of the distal phalanges with progressive resorption of the distal phalangeal tuft. Articular abnormalities are also identified in patients with systemic sclerosis including periarticular osteoporosis as well as bilateral asymmetric erosion. Erosions may be central or in a periarticular distribution often involving both the DIP and PIP joints. In addition, ankylosis may occur.

The most important consideration in the differential diagnosis would be rheumatoid arthritis. This may be especially true early in the course of the disease. Osteoporosis, erosive changes, and flexion deformities are characteristic findings found in both progressive systemic sclerosis and rheumatoid arthritis. One possible differentiating feature is the relative sparing of the metacarpophalangeal joint in systemic sclerosis as opposed to the generally significant changes identified in rheumatoid arthritis.

Reference:
Taveras J. Radiology. Progressive Systemic Sclerosis (Scleroderma).
Lippincott, Philadelphia. 1996;42:1-4.

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