[Osteosis deformans of thyroid origin. Radiological, histomorphometric and pathophysiological study (author's transl)].

A 73-year-old woman with severe, old standing thyrotoxicosis developed osteosis with deformities of the lower limbs and spine resembling osteomalacia. All the well-known radiological, and histomorphometric features of thyroid osteosis were caricaturally present in this patient who, in addition, exhibited curvatures of the lower limbs that are exceptionally described in hyperthyroidism. A study of standard phosphorus/calcium values, 25 OH D values, circulating parathyroid hormone levels and fractional absorption of 47Ca before and after thyroidectomy enables the authors to discuss the current pathophysiological concepts concerning phosphorus/calcium and bone metabolism in hyperthyroid conditions. A possible action of thyroid hormones on vitamin D metabolism or peripheral effects is envisaged.