Surgical treatment of renal angiomyolipoma with inferior vena cava tumor thrombus: case report and literature review

Objective To explore the clinical characteristics of renal angiomyolipoma (AML) with inferior vena cava (IVC) tumor thrombus and to improve the diagnosis and treatment of the disease. Methods The clinical data of 3 patients with renal AML and inferior vena cava tumor thrombus was retrospectively reviewed. The patients were all female, aged 19 to 70 years. Among them, 2 patients presented with lumbago on the right side, and the other one was diagnosed by physical examination. The body mass index ranged from 18.4 to 24.6 kg/m2, with a median value of 20.4 kg/m2. According to the American Society of Anesthesiologists (ASA), they were classified as grade Ⅱ. Color doppler ultrasound examination of the kidney and IVC was performed in all the 3 patients, all of which showed hyperechoic solid mass in the right kidney. Color doppler ultrasound of IVC showed hyperechoic band in the IVC, indicating blood flow signals and the tumor thrombus. All the 3 cases showed irregular fat density or mixed density in the right kidney and multiple irregular fat density were observed in the right renal vein and inferior vena cava on CT. Two of them received MRI examination of IVC, which showed irregular lesions in the right kidney, short T1 and long T2 signals, low lipids, and no definite limited diffusion on DWI. Irregular fat signal were seen in the right renal vein and inferior vena cava. All 3 patients were diagnosed with right renal mass with IVC tumor thrombus, with 1 patient of Mayo grade Ⅲ tumor thrombus and the other 2 of Mayo gradeⅡtumor thrombus. One underwent laparoscopic radical nephrectomy and inferior vena cava tumor thrombectomy, another one underwent open right partial nephrectomy and tumor thrombectomy, and the third one suffered preoperative AML rupture, undergoing open radical nephrectomy and tumor thrombectomy. Results The operation time was 168 to 659 min, with median of 220 min. Intraoperative blood loss ranged from 50 to 300 ml, with the median of 50 ml. Postoperative indwelling time of drainage tube was 5 to 11 days, with the median of 6 days. Postoperative hospital stay ranged from 7 to 14 days, with a median of 8 days. Postoperative follow-up ranged from 12 to 16 months, with a median follow-up of 13 months. All the three patients underwent operation without postoperative complications. Postoperative pathology proved to be right renal angiomyolipoma. After 3 months of follow-up, the patients showed no tumor recurrence or metastasis. Conclusions Renal AML is a benign lesion, which is rarely concurrent with inferior vena cava cancer thrombus. Enhanced CT examination is the main diagnostic method, surgical resection of the lesion is the preferred treatment, partial nephrectomy combined with thrombectomy can be performed in patients with AML, if permitted, and postoperative prognosis turns out to be propitious. Key words: Inferior vena cava; Renal angiomyolipoma; Tumor thrombus