Case report of a giant hypervascular mediastinal mass with airway and SVC compromise managed without preoperative biopsy.

Rationale: To summarize the clinical experience of multidisciplinary management for giant hypervascular mediastinal follicular dendritic cell sarcoma. Patient concerns: A 37-year-old man had a one-week history of progressive dyspnea, orthopnea, and morning facial swelling. Diagnoses: Preoperative imaging suggested Castleman disease as the leading differential diagnosis, and pathological examination confirmed follicular dendritic cell sarcoma (FDCS). Interventions: The patient received an effective strategy under the supervision of multidisciplinary specialists, including 3D reconstruction for precise surgical planning, preoperative angioembolization to reduce vascularity, awake fiberoptic intubation, and video-assisted thoracoscopic surgery (VATS). Learning points: In hypervascular mediastinal tumors, angioembolization of feeding vessels performed on the day of surgery maximally reduces intraoperative bleeding while avoiding complications of prolonged devascularization. When tracheal stenosis and SVC syndrome coexist, a sequential positioning strategy is essential: tumor-side tilt for awake intubation, followed by left lateral decubitus to relieve SVC compression. When biopsy risk is prohibitive, upfront surgical resection offers simultaneous decompression and definitive diagnosis after multidisciplinary discussion.