[Hypocalcemia and myelofibrosis: an unrecognized association]

Observation of a case of myelofibrosis with myeloid metaplasia of liver and spleen associated with hypocalcemia led us to investigate whether this association was fortuitous. We retrospectively analyzed the data of 30 patients with myelofibrosis and identified 9 patients with hypocalcemia out of 22 in whom the plasma calcium level corrected for serum protein could be obtained, i.e. a prevalence of hypocalcemia of 41%. The spleen was significantly larger in the patients with hypocalcemia than in those with normal plasma calcium level, suggesting that hypocalcemia was related to the duration of the disease. In 5 patients with hypocalcemia, biological and/or morphological evidence of osteomalacia was found. It is concluded that an association exists between myelofibrosis and hypocalcemia, possibly as a consequence of a disturbed vitamin D metabolism.