Papillary Thyroid Carcinoma With Cystic Changes in a Patient With Prior History of Toxic Nodule.

Thyroid nodules are palpable on up to 7% of asymptomatic patients. Cancer is present in 8% to 16% of those patients with previously identified thyroid nodules. Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer, accounting for approximately 85% of thyroid cancers. Although most appear as solid nodules on ultrasound imaging, a subset of 2.5% to 6% has cystic components. The presence of cystic changes within thyroid nodules decreases the accuracy of fine needle aspiration (FNA) in the diagnosis of thyroid cancer, given the difficulty of obtaining appropriate cellular content. This becomes a diagnostic and therapeutic challenge. We present a case of a 31-year-old female with a 1-month history of palpitations, fatigue, and night sweats, who underwent evaluation, and was diagnosed with subclinical hyperthyroidism. She presented 4 years later with compressive symptoms leading to repeat FNA, showing Bethesda III-atypia of undetermined significance and negative molecular testing. Thyroid lobectomy revealed PTC with cystic changes. This case is a reminder that patients with hyperfunctioning thyroid nodule should have closer follow-up. It poses the diagnostic dilemma of how much is good enough in the evaluation and management of a thyroid nodule. Early detection and action should be the standard of care.