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A 20-year-old woman was admitted with complaints of fever and polyarthralgia since January 1996. All investigations including collagen markers were negative. The patient was treated with analgesics and showed improvement. In July she noticed a thyroid swelling with low-grade fever, and investigations showed that she was hypothyroid. Antimicrosomal antibodies were positive and antithyroglobulin was negative. Thyroid receptor antibody status was not available. Thyroid fine needle biopsy showed chronic lymphocytic thyroiditis. She was put on thyroid hormone replacement therapy.
In February 1997 she noticed multiple subcutaneous lumps in the lower limbs. She also complained of low-grade fever and arthralgia. There was no malar or discoid rash or rash elsewhere on the body. On examination, the lumps were hard, mobile, and non-tender, varying in size from 3–7 cm. She was febrile and had swelling of the small joints of both hands. Investigations showed normal blood picture, erythrocyte sedimentation rate was 130 mm in 1st hour, ANA and dsDNA both were strongly positive. Anti-Sm, and antiphospholipid antibodies (IgG, IgM) were negative. Lupus anticoagulant was positive. Echocardiography showed mild pericardial effusion. Chest X-ray was normal and X-ray of the hands did not show any erosion. Liver, renal function tests, serum calcium, phosphorus, alkaline phosphatase, parathyroid levels, creatine phosphokinase, barium swallow and pulmonary functions test were all normal. Rheumatoid factor was negative. X-Rays of the lower limbs are shown in figures 1 and2.
X-Ray of the lower limbs
X-Ray of the lower limbs
Questions
- 1
- What are the X-ray findings?
- 2
- What is the diagnosis?
Answers
QUESTION 1
Extensive calcification in subcutaneous tissue of lower limbs.
QUESTION 2
Calcinosis cutis in systemic lupus erythematosus (SLE). The patient fulfilled the criteria of the American Rheumatism Association for the diagnosis of SLE. Fine needle biopsy from the nodules showed calcium deposits in subcutaneous tissues and was consistent with the diagnosis of calcinosis cutis.
Discussion
Calcium deposits in the skin can occur in connective tissue disorders such as dermatomyositis and scleroderma. Although calcinosis cutis in such collagen disorders is not rare, its occurrence in cases of SLE is,1 and only 30 cases have been reported. Calcinosis cutis is extremely rare in mixed connective tissue disorders.2 Although it is common in scleroderma, it is rare in morphea and was reported in only one of 74 patients by Muller.3 The clinical examination of our patient was not suggestive of such a disorder.
Calcinosis cutis may be an incidental finding or may present as subcutaneous tumours. The calcinosis may involve a small area (circumscripta) or be diffuse (universalis). In dermatomyositis, the calcium deposits occur in shoulders and hips of young men. The deposits are usually large,4 in contrast to scleroderma in which they are small and occur in fingers of adults.3 All the above conditions are examples of dystrophic calcification and the product of serum calcium and phosphorus levels is not raised The exact mechanism of calcification in SLE is not known. The proposed mechanism involves trauma and inflammation, which denature the protein in necrotic tissue. The phosphates bind to denatured protein and act as a nidus for calcification. The other mechanism involves the increased activity of alkaline phosphatase in the local tissue by lysosomes leading to calcification. Although intralesional steroids, aluminum hydroxide, and etidronate have been shown to be useful, medical treatment is usually not successful. Surgical excision of the lesion with skin grafting has been recently shown to be beneficial.1 Our patient was unusual as she had calcinosis cutis associated with relatively mild SLE which was of shorter duration.
Our patient also had thyroid involvement, the prevalence of which is 7.5% in cases of SLE.5 This prevalence is greater than that seen in the general population. In SLE, thyroid function tests are frequently abnormal and thyroid autoantibodies may be present without disease being actually present. Thyroid disease in SLE occurs before the diagnosis of SLE is made or after stopping the immunosuppressive therapy.5
Dermopathy in primary hypothyroidism or chronic lymphocytic thyroiditis is exceptionally rare.6 In 15–20% patients with Graves' disease, there is dermopathy over the dorsal surface of the legs or feet called pretibial myxoedema.6 This commonly presents with ophthalmopathy and is a late manifestation of Graves' disease. Older patients are more at risk for developing this dermopathy.7 The affected area is raised, circumscribed and thickened. It has a peau d‘orange-like appearance. There is a localised area of hyperpigmented and non-pitting oedema. The lesions may rarely be plaque, nodular or polypoidal. Histologically there is lymphocyte infiltration and metachromatic material is seen in the deeper layers of the dermis.8
In calcinosis cutis the lesions may be diffuse and bilateral and commonly occur in lower limbs.1 The calcification occurs in a diffuse, linear, streaky or nodular form. Calcifications may also be plaque-like along the anterior aspect of lower limbs; they are hard on palpation. There may be associated myopathy, peripheral vascular calcification, or skin ulcerations. The skin biopsy in these patients may show extensive deposition of collagen in dermal and subcutaneous tissue with calcification.
Final diagnosis
Thyroiditis with calcinosis cutis universalis in SLE.