Tumoral calcinosis: evidence for concurrent defects in renal tubular phosphorus transport and in 1 alpha,25-dihydroxycholecalciferol synthesis.
A 50-year-old Latin American man with tumoral calcinosis presented with hyperphosphatemia (6.62 +/- 1.04 SD mg/dl), elevated renal threshold phosphorus concentration (TmP) (7.3 mg/GFR), and 1,25-dihydroxyvitamin D [1,25-(OH)2D] (69 pg/ml) hypercalciuria (239 mg/day), and a high fractional intestinal calcium (Ca) absorption (0.74). Sodium cellulose phosphate therapy (20 g/day) lowered urinary Ca, and partially reduced serum phosphorus (P) and TmP to 5.91 +/- 0.63 mg/dl and 6.2 mg/GFR, respectively. Serum 1,25-(OH)2D remained elevated at 58-64 pg/ml. Amphojel therapy (4 oz/day) decreased urinary P to 23 +/- 21 mg/day and lowered serum P to 5.75 +/- 0.36 mg/dl (P < 0.05). TmP increased to a value of 8.0 mg/GFR while serum 1,25-(OH)2D continued to remain elevated at 53 pg/ml. This case illustrates the probable operation of dual abnormalities in tumoral calcinosis represented by augmented renal conservation of P and an elevation in the circulating concentration of 1,25-(OH)2D.
D002114:Calcinosis / Q000209:etiology* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D004100:Dihydroxycholecalciferols / Q000378:metabolism*; D006801:Humans; D006887:Hydroxycholecalciferols / Q000378:metabolism*; D007592:Joint Diseases / Q000209:etiology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands / Q000378:metabolism; D010281:Parathyroid Hormone / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism*; D015499:Renal Tubular Transport, Inborn Errors / Q000150:complications* / Q000378:metabolism
D004100:Dihydroxycholecalciferols; D006887:Hydroxycholecalciferols; D010281:Parathyroid Hormone; D010758:Phosphorus; D002118:Calcium