A case of severe hypothyroidism due to lenalidomide.

Lenalidomide, an immunomodulatory drug often used to treat multiple myeloma, can cause hypo- or hyperthyroidism. We present a patient being treated with lenalidomide for 2 years who developed severe hypothyroidism that was complicated by rhabdomyolysis and acute kidney injury. Thyroid function tests should be serially monitored in patients taking lenalidomide.