Case Author(s): Ed Grishaw, M.D. and Henry Royal, M.D. , 10/23/96 . Rating: #D3, #Q4

Diagnosis: Soft tissue calcinosis secondary to lupus erythematosus.

Brief history:

44-year old woman with systemic lupus erythematosus

Images:

Anterior and posterior whole body scintigrams

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Full history/Diagnosis is available below

Diagnosis: Soft tissue calcinosis secondary to lupus erythematosus.

Full history:

44-year old woman with systemic lupus erythematosus and calcinosis cutis universalis.

Radiopharmaceutical:

21.6 mCi Tc-99m MDP i.v.

Findings:

Anterior and posterior whole body scintigrams demonstrate extensive abnormal radiopharmaceutical uptake within the soft tissues within a predominantly appendicular distribution. Plain films reveal extensive soft tissue calcification in areas of abnormal radiopharmaceutical uptake.

Renal enlargement is likely secondary to acute glomerulonephritits

Discussion:

Calcinosis cutis in systemic lupus erythematosus represents dystrophic calcification. In dystrophic calcification serum levels of calcium phosphorus are normal. This type of calcification occurs commonly in connective tissue disease, particularly dermatomyositis and scleroderma; however, it is only rarely seen in systemic lupus erythematosus. When this disorder occurs in systemic lupus erythematosus, it typically affects women late in the course of longstanding and severe disease. Spontaneous resolution is atypical.

The pathophysiology of calcinosis cutis is unclear. Local elevations in alkaline- phosphatase activity may prevent pyrophosphate inhibition of calcium deposition. Another proposed mechanism is nidus formation produced by phosphate binding to DNA proteins of necrotic cells at sites of inflammation or trauma. Lastly,local tissue injury may produce increased cell membrane permeability allowing influx of calcium, which exceeds the mitochondrial capacity to sequester the mineral. Subsequently, the mitochondria release this calcium phosphate to matrix vesicles which have been proposed as the site of initial extracellular calcium deposition.

Therapy of calcinosis is primarily medical. Intralesional injections of steroids is occasionally effective. Etidronate disodium, a diphosphonate, has been used to inhibit biomineralization. Excessive dosages have led to fractures and osteomalacia, however. Alumina hydroxide ,an oral phosphate binding agent ,has been useful in some cases of calcinosis due to dermatomyositis. Surgical therapy for symptomatic relief of calcinosis cutis has also been proposed but the effectiveness of this therapy remains to be proven.

References: 1) Cuzins, et al. Surgical management of calcinosis cutis universalis and systemic lupus erythematosus. (In press).

2) Rothe, et al. Extensive calcinosis cutis with systemic lupus erythematosus. Arch of Derm 126(8): 1060-1063, 1990.

3) Weinberger, et al. Extensive soft tissue calcification (calcification universalis) in systemic lupus erythematosus. Ann Rheum Dis 38:384-386, 1979.

Followup:

To control the dystrophic calcification, the patient will be placed on probenecid.

Differential Diagnosis List

Dermatomyositis, polymyositis, electrical burns, idiopathic calcinosis universalis, scleroderma, mixed connective tissue disease.

ACR Codes and Keywords:

References and General Discussion of Bone Scintigraphy (Anatomic field:Skeletal System, Category:Metabolic, endocrine, toxic)

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Case number: bs068

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