Complete Resection of a Giant Middle Mediastinal Castleman Disease Using Robot-Assisted Thoracic Surgery: A Case Report.

INTRODUCTION: Castleman disease is a rare benign lymphoproliferative disorder characterized by lymph node hyperplasia. Unicentric Castleman disease (UCD) involves a single anatomical region. Complete surgical resection remains the standard treatment. Lesions in the middle mediastinum can become large and technically demanding because of their proximity to the trachea, esophagus, and major vessels. Although video-assisted thoracoscopic surgery has been used in selected cases, reports of robot-assisted thoracic surgery (RATS) for giant UCD arising in the subcarinal middle mediastinum remain extremely limited. Herein, we report a case illustrating the feasibility and potential advantages of RATS in the treatment of giant middle mediastinal UCD. CASE PRESENTATION: A man in his 40s was incidentally found to have a 9.2 × 6.4 cm middle mediastinal mass beneath the tracheal bifurcation on chest imaging. The patient was asymptomatic, and laboratory tests, including interleukin-6 and tumor markers, yielded normal results. Fluorodeoxyglucose PET/CT demonstrated a homogeneous lesion with mild uptake. Endobronchial US-guided transbronchial needle aspiration was nondiagnostic, and upper gastrointestinal endoscopy showed no direct invasion of the esophagus. Although UCD was suspected, the differential diagnoses included malignant lymphoma and a solitary fibrous tumor. Complete surgical resection was planned for both diagnosis and treatment because of the uncertain diagnosis, the tumor size, and its location. The tumor was mobilized and removed en bloc using right-sided RATS with 4 robotic ports and 1 assistant port. The robotic platform provided 3D visualization, articulated instrumentation, and precise dissection, particularly around the right main bronchus, esophagus, azygos vein, and posterior aspect of the tumor. The operative time was 311 min, and the estimated blood loss was 200 mL, with no major intraoperative bleeding or postoperative complications. Histopathology confirmed hyaline-vascular-type UCD, and margin-negative resection was achieved. The postoperative recovery was uneventful, and the patient was discharged on POD 5. CONCLUSIONS: When combined with meticulous preoperative planning and strategic port placement, RATS may offer a feasible minimally invasive approach for managing large mediastinal tumors in challenging locations.