Objective : Lenalidomide is thalidomide analogue and is an immunomodulatory drug used for treatment of multiple myeloma and solid tumors. It has been seen to cause thyroid abnormality including hypothyroidism but rarely thyrotoxicosis. We present a case of lenalidomide induced thyrotoxicosis.
Methods : Clinical
Case: A 58-year-old female with past medical history of multiple Myeloma, bronchial asthma, anxiety and depression was referred to us for thyrotoxicosis which was found during a pre-transplantation work-up for multiple myeloma. She was symptomatic with night sweats, palpitation and fatigued. She denied history of neck pain, compressive symptoms, family history hyperthyroidism and any recent viral infection. She also denied taking any supplement containing thyroid. Review of medicines from her oncologist showed that she was started on Bortezomib, Cyclophosphamide and dexamethasone initially but stopped due to lack of response. Then she was started on Lenalidomide. On examination, thyroid gland found to be of normal size, without any palpable nodule and it was non-tender. There were no signs of orbitopathy. Lab review revealed her TFTs, after about 2 months of being on Lenalidomide, were TSH <0.01 iu/ml (0.36 - 3.74), Free T4 – 1.75 ng/dl (0.76 – 1.46). Thyroid stimulating immunoglobulin was within normal range. Repeat TFT on subsequent laboratory check had normalized and thyroid ultrasound was normal as well.
Results : N/A
Discussion : Drug induced thyrotoxicosis is not uncommon. But, to our knowledge, there is only 1-2 cases of Lenalidomide induced thyrotoxicosis have been reported. Lenalidomide is currently being used in the treatment of mantle cell lymphoma, multiple myeloma and myelodysplastic syndrome. As per FDA package inserts, it can cause both hypo and hyperthyroid. Our case recovered within 2 months, but it is unknown at this time whether it will be transient in other cases as well. Because it is rare, it is necessary to rule out other causes first
Conclusion : This case highlights the importance of monitoring thyroid function in the growing number of patients being treated with lenalidomide.
Louisiana State University, Shreveport
Clinical Fellow - Department of Endocrinology and Metabolism, Louisiana State University, Shreveport, LA, USA.
Assistant Professor of Clinical Medicine
LSU Health Shreveport
Assistant Professor of Clinical Medicine LSU Health Shreveport, Louisianan, USA. Section of Endocrinology