Idiopathic tumoral calcinosis.

Abstract

A 22-year-old man had a recurrent mass in the sole of the right foot. Although he had been asymptomatic for approximately i5 years after a previous operation, he had noticed swelling and tendemess for several months. The patient was hyperphosphatemic, but renal function and serum calcium, alkaline phosphatase, and parathyroid hormone levels were normal. Plain films of the foot showed a 7-cm, multiglobular, calcified soft-tissue mass on the planter aspect of the forefoot (Fig. 1). CT showed discrete, rounded, 2to 20-mm CaICIfIC foci, some with homogeneous attenuation and some with sedimentation levels. The adjacent bones were normal. A local excision showed the lesion to consist of multiple calcific deposits surrounded by chronic foreign-body reaction and fibrosis. The calcareous material had the consistency of toothpaste. The final pathologic diagnosis was idiopathic tumoral calcinosis. Idiopathic tumoral calcinosis is thought to result from a heritable error in phosphorus metabolism that leads to extracellular deposition of calcium hydroxyapatite crystals [i , 2]. These are seen most frequently in the form of periarticular soft-tissue masses. Suspended calcium salts may layer out within cystic structures. The surrounding granulomatous foreign-body response to the deposits results in bright signal on T2-weighted MR images [1]. Because the deposits are active metabolically, radionuclide bone scans show abnormal accumulation. Idiopathic tumoral calcinosis is rare and appears to have autosomal dominant transmission and various clinical signs and symptoms. More common in blacks than in other racial groups, the most frequent age of presentation is during childhood or adolescence. The lesions enlarge slowly, may attain large size, and may become symptomatic by virtue of local mechanical effects. If incompletely resected, they may recur. Other manifestations include elevated i ,25-dihydroxyvitamin D3 levels (not measured in this case), calcific myelitis, and dental abnormalities. Dietary restriction of phosphorus may be beneficial in some patients; surgical excision is reserved for symptomatic lesions. The radiologically indistinguishable condition of secondary tumoral calcinosis may occur in association with such disorders as chronic renal failure or scleroderma.