Hand #2 - Answers

1. Scleroderma.

Findings:

1. acro-osteolysis.
2. soft tissue calcinosis.
3. soft tissue atrophy, especially at fingertips (sclerodactyly).

The differential diagnosis of the first two findings is potentially a long one. However, when we compare the differential lists for them, their intersection forms a much shorter list.

The differential diagnosis for acro-osteolysis might include:

• scleroderma
• hyperparathyroidism
• thermal injury
• psoriasis
• neuroarthropathy
• trauma
• diabetes mellitus
• leprosy
• etc.

The differential diagnosis of soft tissue calcinosis might include:

• Collagen-vascular disease
• scleroderma
• dermatomyositis
• Ehlers-Danlos syndrome
• Metabolic diseases
• hyperparathyroidism
• gout
• tumoral calcinosis
• Trauma
• hematoma
• burn
• heterotopic ossification
• Infection (tuberculosis)
• Malignant osteosarcoma (parosteal, metastatic or primary soft-tissue)

So, these two lists intersect with scleroderma and trauma. Of these two, scleroderma is the more likely, especially since it also explains the soft tissue wasting at the fingertips seen in this case.

Scleroderma (progressive systemic sclerosis) is an uncommon generalized disorder of connective tissue of unknown etiology. Abnormalities of collagen metabolism, vascular abnormalities, and immunologic abnormalities have been implicated in the pathogenesis of scleroderma.

The major findings in this disorder include skin changes, bone resorption, and soft tissue calcification. Raynaud's phenomenon is common. The disorder affects women more frequently than men, and usually had its onset in the third to fifth decades of life.

Articular involvement may be seen in 10 - 65 % of patients, usually affecting the fingers, wrists and ankles. Tendon and tendon sheaths are also commonly involved.

References:

1. Resnick D. Bone and joint imaging. Philadelphia, WB Saunders, 1989.

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