Vanishing Papillary Thyroid Carcinoma: Morphological Changes After Fine-Needle Aspiration

Abstract

Objective: Fine-needle aspiration (FNA) of a thyroid nodule is typically considered a benign procedure. Uncommonly, morphological changes can occur in the nodule or tissue after the procedure. These changes have been noted in tissues like thyroid, breast, lymph node, and prostate. The objective of this case report is to report the rare occurrence of thyroid cancer diagnosed on FNA, appearing as a necrotic mass after near total thyroidectomy and to emphasize the need for confirmation of diagnosis with histopathology. Methods: A 69-year-old man was seen for a self-discovered neck mass. Thyroid ultrasound demonstrated a thyroid nodule with suspicious features. Ultrasound-guided FNA of the nodule was performed with a 22-gauge needle without immediate complications. Results: The cytology was read as consistent with papillary thyroid cancer with a preoperative thyroglobulin level of 15,288 ng/mL (normal range is 1.6–55 ng/mL). After a near total thyroidectomy, histopathology revealed complete infarction of the tumor with no evidence of cancerous tissue remaining. Based on the pathology report, he was considered cured of the cancer and did not receive radioactive iodine therapy. Conclusion: The occurrence of tissue infarction following FNA of a thyroid nodule is rare, reportedly <2%. We conclude a review of the original cytology material and a thorough examination of remaining viable tissue be made. Complete evaluation for invasion of the capsule or surrounding tissue must be ascertained to decrease diagnostic errors.