S2491 Diagnosis of Papillary Thyroid Carcinoma by Transesophageal Endoscopic Ultrasound-Guided Fine-Needle Biopsy (EUS-FNB)

Abstract

Introduction: Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) can be used as a diagnostic modality with tissue sampling of both intra- and extra-luminal lesions. EUS allows for a less invasive, real-time image-guided biopsy of adjacent extraluminal structures. We present EUS-guided FNB evaluation in a patient with suspected recurrent thyroid cancer and a suspicious portocaval lymph node (PCNL). Case Description/Methods: A 36-year-old male with recurrent papillary thyroid cancer that had been previously treated with total thyroidectomy and modified radical neck dissection and iodine ablation presents with intermittent dysphagia to solid foods and a pressure sensation in his mid-neck. He reported poor compliance with follow-up appointments, surveillance imaging, and post-treatment TSH-suppressive T4 therapy. CT neck showed non-specific bilateral nodular changes in the thyroidectomy bed which were thought to reflect postsurgical changes versus recurrent neoplasm. A whole-body PET/CT showed no substantial FDG uptake in the neck but rather increased uptake in a PCNL concerning for intra-abdominal metastases. Surface ultrasound-guided FNA (USG-FNA) of the left neck mass was non-diagnostic. As the lymph node was inaccessible by percutaneous biopsy, and previous USG-FNA of thyroid bed was non-diagnostic, a EUS guided biopsy of both, the left neck mass and PCNL was pursued. The EUS revealed a 12mm x 8mm mass in the thyroid resection bed. EUS-guided thyroid biopsy was performed from the level of the upper esophageal sphincter, with 5 passes of a 25 gauge SharkCoreTM needle (C-25-05 Medtronic, Dublin, Ireland). Two enlarged ( >1cm) hypoechoic PCNL with well-defined borders were identified with EUS. Using a 22 gauge SharkCoreTM needle biopsy, FNB x 3 was performed on the PCNL. The pathology from the left thyroid mass revealed papillary thyroid carcinoma, and the histopathology from the PCNL was a benign lymphoid sample. The patient did well on follow-up and had no periprocedural adverse events. By demonstrating recurrent cancer, without PCNL involvement. This allowed the patient to undergo local surgical resection. Discussion: The evaluation and management of suspicious lesions in the superior mediastinum have evolved since the inception of EUS. We demonstrate that EUS can be used in the evaluation of recurrent thyroid cancer when USG-FNA is not diagnostic. An additional advantage of EUS is the ability to sample suspicious lymph nodes adjacent to the GI tract at the same time.Figure 1.: EUS guided fine needle biopsy of the enlarged lymph node in the porta hepatis region (a) revealed a benign lymphoid sample (c). A 1.2 x 0.8 cm lesion found in the left thyroid bed on EUS (b) with EUS-FNB showing malignant cells diagnostic of papillary thyroid carcinoma (d).