Port-Site Implantation Diagnosed by Iodine-131 Post-Ablation Single-Photon Emission Tomography-Computed Tomography After Robotic Thyroidectomy: A Case Report

Objective: Unusual or unexpected effect of treatment Background: Robotic thyroidectomy using remote access approaches is currently regarded as the optimal surgical protocol for highly selected patients. This approach has excellent cosmetic outcomes compared with conventional open transcervical thyroidectomy. Although the remote access approach offers significant benefits, it can cause complications associated with the large working space required for surgery. Such complications can lead to unusual imaging findings. Case Report: We report a case of a 37-year-old woman with thyroid cancer who underwent robotic thyroidectomy and demonstrated unusual port-site implantation findings on post-treatment iodine-131 whole-body scintigraphy and single-photon emission computed tomography-computed tomography. Evaluation of stimulated thyroglobulin and additional imaging studies did not reveal any remarkable findings. Through a multidisciplinary discussion, we discovered that the bag had developed a tear during specimen retrieval. Our patient was administered a therapeutic dose of radioiodine, which accumulated within the target area and successfully ablated the implanted tissue. Follow-up imaging and biochemical studies were normal after a follow-up period of 7 years. Conclusions: Port-site seeding is a rare and unexpected surgical complication; however, it can be treated with radioiodine therapy involving a therapeutic dose. Meticulous surgical manipulation is essential to prevent port-site implantation related to spillage and tearing of thyroid or cancer tissue. Awareness and identification of these rare complications, which manifest as unusual imaging findings, are critical for improving the accuracy of interpretation.