Abnormal vitamin D metabolism in Hodgkin's lymphoma.

In the autumn of 1984 there was spontaneous correction of hypercalcaemia in a patient with Hodgkin's lymphoma. Hypercalcaemia recurred when ultraviolet radiation (UVR) was given and this abnormality was associated with high serum concentrations of 1,25-dihydroxyvitamin D3 (1,25[OH]2D3) although concentrations of precursor 25-hydroxyvitamin D3 were normal. Chemotherapy of Hodgkin's lymphoma corrected the hypercalcaemia and subsequent exposure to UVR did not produce either hypercalcaemia or a high serum 1,25(OH)2D3. Rigorous tests were applied to the putative 1,25(OH)2D3 produced during hypercalcaemia and it was not possible to separate this metabolite from 1,25(OH)2D3 itself. It is concluded that the hypercalcaemia was caused by abnormal vitamin D metabolism which was a result of the Hodgkin's lymphoma. Hodgkin's tissue may have been the site of excessive synthesis of 1,25(OH)2D3.