A DRAMATIC RESPONSE TO DENOSUMAB: PROTRACTED HYPOCALCEMIA RELATED TO HUMAN T-CELL LYMPHOTROPIC VIRUS TYPE 1-ASSOCIATED ADULT T-CELL LEUKEMIA/LYMPHOMA.

OBJECTIVE

Adult T-cell leukemia/lymphoma (ATL) is known for its aggressive behavior, frequently presenting with hypercalcemia. ATL tumor cells uniquely secrete parathyroid hormone-related protein, viral peptides, and inflammatory cytokines, inducing a state of high bone turnover and activation of the receptor activator of nuclear factor kappa-B signaling pathway resulting in hypercalcemia.

METHODS

A 54-year-old woman diagnosed with ATL presented with severe hypercalcemia refractory to bisphosphonate therapy. Treatment with denosumab was followed by protracted hypocalcemia and hypophosphatemia lasting approximately 5 months.

RESULTS

Hypercalcemia due to acute ATL was responsive in this case to denosumab therapy.

CONCLUSION

Clinicians should be aware of the possibility of protracted hypocalcemia in patients with ATL exposed to denosumab therapy.