腎臟上皮樣血管平滑肌脂肪惡性腫瘤合併陰道及肺轉移 − 案例報告
Malignant Renal Epithelioid Angiomyolipoma with Vaginal and Pulmonary Metastases – Case Report
Chih-Heng Chen, Yu-Chuang Lu
Department of Urology, National Taiwan University Hospital
Introduction: Epithelioid angiomyolipoma (eAML) of kidney, a rare variant of AML, is a subtype of perivascular epithelioid cell tumors (PEComas) with malignancy potential. Extrarenal metastasis to liver, lung and bone have been mentioned in previous cases. Here we presented a case of eAML with vaginal and pulmonary metastases in the initial presentation.
Case presentation: A 61-year-old menopausal woman presented to the outpatient clinic with vaginal bleeding for 1 week. A 1-year history of right abdominal bloating was also reported. On physical examination, there was a mass at right lateral wall of vagina, and abdominal palpation showed a non-tender mass in the right hemiabdomen. The biopsy of the vaginal mass disclosed PEComas. Subsequent enhanced computed tomography scan revealed a huge, heterogeneous mass (21.0 cm by 20.3 cm by 12.7 cm) originating from lower pole of right kidney (Figure 1, white arrow) and another mass at right lower vagina (Figure 1, yellow arrow). Besides, multiple nodules were noticed in bilateral lung field. Right radical nephrectomy with retroperitoneal tumor excision, and partial vaginectomy were performed. The dissected surface of renal tumor was well-circumscribed with focal hemorrhage and necrosis (Figure 2). Histopathological examination confirmed malignant eAML of right kidney with vaginal metastasis. Genetic testing for tuberous sclerosis complex (TSC) revealed no germline mutation of TSC1/2. After the surgery, adjuvant treatment was initiated with sirolimus. No disease progression was noted at 18-month follow-up.
Renal eAMLs, an uncommon subtype of PEComa, is accounting for 4.6% of all renal AML. Unlike the classic AML, about one-third of eAML patients developed distant metastases. Strong relationship between nearly all types of PEComas and genetic mutation of TSC, an autosomal dominant genetic disorder caused by losses of TSC1/2, was reported. Previous study demonstrated that some adverse prognostic factors, including associated TSC or concurrent AML, tumor necrosis, tumor size>7cm, extra renal extension and/or renal vein invasion, and carcinoma-like growth pattern, were associated with significantly high risk of disease progression.Radical nephrectomy is the gold standard treatment for this aggressive disease. Neoadjuvant or adjuvant mammalian target of rapamycin (mTOR) inhibitors, such as everolimus, sirolimus, or temsirolimus, may lead to better clinical outcomes.