Thyroid Swelling and Thyroiditis in the Setting of Recent hCG Injections and Fine Needle Aspiration

A 60-year-old woman presented with a neck mass and underwent fine needle aspiration of a left thyroid nodule. During this time, she had been injected with hCG for weight loss. Soon after, she developed rapid diffuse thyroid growth with pain. She was ultimately diagnosed with thyrotoxicosis due to postaspiration subacute thyroiditis and subsequently became hypothyroid. This condition is rare in the nonpregnant state in noncystic nodules with a smaller needle gauge approach. The incidence of thyroid nodule discovery and evaluation is increasing. As more procedures are undertaken, understanding of potential complications is important. This case highlights potential complications of thyroid fine needle aspiration including diffuse thyroid swelling and thyroiditis. The role of hCG injections is speculated to have potentially stimulated thyroid follicular epithelium via cross-reactivity with the TSH receptor and contributed to the acute inflammatory response after fine needle aspiration.