Superior vena cava (SVC) syndrome results from clear cell renal cell carcinoma and is a challenge in clinical practice due to its pathological complexity and a lack of research data. The current study presents a 49-year-old female with symptoms of exertional dyspnea and increased fatigue, which had persisted for 15 months, as well as bilateral edema in the lower limbs for two days. A transesophageal echocardiogram demonstrated a right atrial mass originating from the inferior vena cava (IVC; size, 14×8 cm) that caused a tricuspid inflow obstruction. Following a partial resection of the thrombus, a clear cell renal cell carcinoma was identified by histological examination. The patient received intensity-modulated radiation therapy following refusal of other therapeutic methods. The eleven-month follow-up indicated that the tumor on the kidney and IVC was stable. Intensity-modulated radiation therapy may be beneficial to patients with clear cell renal cell carcinoma and SVC syndrome. However, additional studies are required to obtain further data regarding the treatment of this syndrome.