Renal Lipoma-Like Angiomyolipoma of Tumour Thrombus Extending to the Confluence of Inferior Vena Cava with Right Atrium: A Rare Case Report and Literature Review

Angiomyolipoma (AML) complicated with tumour thrombus extending to the confluence of inferior vena cava (IVC) with right atrium is rarely observed. We report a female AML patient admitted to our centre on January 21, 2020, with complication of tumour thrombus extending to the confluence of IVC with right atrium and had no sign of difficult breathing. She underwent whole-abdominal enhanced CT for abdominal pain and was diagnosed with a possible renal AML with tumour thrombus. Open radical nephrectomy and thrombectomy of vena cava were performed. Intraoperative transoesophageal echocardiography indicated that the tumour thrombus has reached the confluence of IVC with right atrium. The operation took 255 min with an intraoperative haemorrhage of 800mL. The patient was discharged 7 days after surgery. Pathology revealed lipoma-like AML. Immunohistochemistry showed vimentin (+), EMA (-), HMB45 (+), S-100 (-), SMA (+), TFE-3 (-), melan A (+). After 2 years of follow-up, we found that the patient showed full recovery and had no recurrence. Therefore, lipoma-like AML should also be followed closely for recurrence and metastasis. When AML involves IVC tumour thrombus, open thrombectomy and radical nephrectomy are safe and effective methods.