Endoscopic detection of near-infrared autofluorescence in the parathyroid glands: a case report of two patients

Introduction and importance: Preservation of the parathyroid glands during thyroid surgery is crucial to prevent postoperative hypocalcemia. Parathyroid glands exhibit intrinsic autofluorescence with an emission peak around 820 nm, and near-infrared imaging has been applied for their intraoperative identification. However, its feasibility in endoscopic thyroid surgery remains unclear, particularly when using a small-diameter endoscope. Here, we report two cases in which parathyroid autofluorescence was successfully visualized during endoscopic surgery using a 5-mm endoscope. Case presentation: The first patient was a 75-year-old woman with breast cancer who was referred to us with a right thyroid nodule detected on preoperative positron emission tomography/computed tomography. Fine-needle aspiration cytology suggested papillary carcinoma, and as the nodule gradually enlarged, we performed a right thyroid lobectomy after 7 years using video-assisted neck surgery (VANS) with a 5-mm endoscope. A parathyroid gland on the posterior thyroid surface showed homogeneous and strong autofluorescence. The second patient was a 53-year-old woman with primary hyperparathyroidism who presented with hypercalcemia and elevated intact parathormone levels. We performed a right parathyroidectomy using VANS with the same endoscope. A parathyroid tumor showing heterogeneous and relatively weak autofluorescence was identified on the posterior aspect of the right thyroid lobe. Clinical discussion: In both cases, near-infrared imaging revealed parathyroid autofluorescence during VANS. Adequate display settings, including enhanced brightness and contrast, appear to be important for clear visualization. Conclusion: Parathyroid autofluorescence can be visualized even during endoscopic thyroid surgery with a 5-mm endoscope and may contribute to safer procedures.