Hypercalcemia, unusual bone lesions, and human T‐cell leukemia‐lymphoma virus in adult T‐cell lymphoma

Extensive generalized and subperiosteal bone resorption was demonstrated in a patient with adult T‐cell lymphoma and marked hypercalcemia of unclear pathogenesis. Antibody to the human T‐cell leukemia‐lymphoma virus (HTLV) was present in the serum of the patient, consistent with the recently reported association of adult T‐cell lymphoma, hypercalcemia, and HTLV. The unique feature of this case was the presence of bone radiographic and pathologic findings consistent with hyperparathyroidism, in the absence of elevated parathormone levels. These findings contrast with the few previously reported cases of adult T‐cell lymphoma with hypercalcemia, which showed lytic, sclerotic, or osteoporotic bone lesions. The authors suggest that the patient's malignant T‐lymphocytes may have produced an osteoclast‐activating‐factor‐like substance or a parathormone‐like substance, which caused the striking bone changes. The exact role of HTLV in the pathogenesis of such cases remains to be determined.