Recurrent Painless Thyroiditis With Sequential Thyrotoxicosis and Hypothyroidism After 2 Courses of Lenalidomide

Abstract

ABSTRACT: Objective: Lenalidomide is a thalidomide analogue used to treat multiple myeloma, myelodysplastic syndromes, and solid cancers. It has been associated with thyroid abnormalities, mostly primary hypothyroidism, though rarely thyrotoxicosis. We present a case of lenalidomide-induced painless thyroiditis with initial thyrotoxicosis presentation followed by hypothyroidism requiring levothyroxine treatment in a 62-year old male with diffuse large B-cell lymphoma.Methods: The identified case is described.Results: The patient had no history of thyroid disease, with normal baseline thyroid function tests prior to lenalidomide treatment. He developed painless thyrotoxicosis after 1 week of treatment. The thyrotoxicosis resolved spontaneously, and he became euthyroid after withholding lenalidomide for 6 weeks. He was then restarted on a lower dose and developed recurrent painless thyroiditis 2 weeks later, with suppressed thyroid-stimulating hormone (TSH) of 0.05 μU/mL and elevated free thyroxine (FT4) of 2.02 ng/dL, prompting a more detailed evaluation. His thyroid-stimulating immunoglobulin, thyroperoxidase (TPO), and thyroglobulin (Tg) antibodies were not elevated. Tg was significantly elevated at 679 ng/mL. A thyroid pertechnetate scan revealed minimal uptake. There were no interim medication changes, recent iodine load, viral illness, or amiodarone or interferon treatment, suggesting he had lenalidomide-induced thyroiditis. Thyrotoxicosis again spontaneously resolved, but 3 months later, he developed hypothyroidism that required levothyroxine. Lenalidomide was later stopped, but the patient has continued to require levothyroxine therapy.Conclusion: As the medical uses for lenalidomide expand, this case stresses the importance of monitoring thyroid function in patients taking lenalidomide.Abbreviations: DLBCL = diffuse large B-cell lymphoma FT4 = free thyroxine Tg = thyroglobulin TPO = thyroperoxidase TSH = thyroid-stimulating hormone