Podium 01
案例報告: 模仿腎細胞癌合併腎靜脈栓塞的罕見腫瘤-類上皮細胞型腎臟血管肌肉脂肪瘤
葉星佐、羅浩倫
高雄長庚紀念醫院泌尿科
Case Report: A Rare Tumor Mimicking Renal Cell Carcinoma with Renal Vein Thrombus - Epithelioid Angiomyolipoma
Hsing-Tsuo, Yeh, Hao-Lun Luo
Kaohsiung Chang Gung Memorial Hospital, Department of Urology
Introduction: Epithelioid angiomyolipoma (EAML) of the kidney is a rare variant of angiomyolipoma with malignant potential. Due to its low percentage of fat, it is difficult to distinguish EAML from renal cell carcinoma(RCC) and fat‑poor AML on CT or MRI preoperatively, which may lead to misdiagnosis. Here we report a case of renal mass with renal vein thrombus, which was thought to be RCC at first, but then turned out to be renal EMAL.
Case Report: This 53-year-old female has underlying disease of eczema, anxiety, major depressive disorder, and migraine. She was presented with right flank pain for 5 days. Thus, she went to local medical department for first aid, where abdominal CT found a 4.3 cm heterogenous mass at upper pole of right kidney. Biopsy was done there, which revealed xanthogranulomatous inflammation. She was then referred to our hospital for further survey. Physical exams were unremarkable. Urine analysis showed bacteriuria, blood tests reported microcytic anemia (Hb 8.1g/dL), tumor markers were all within normal range. MRI showed a 5x6 cm right renal upper pole mass with enhancement, compatible with renal cell carcinoma cT2N0 (AJCC 8th edition). However, pathology from biopsy showed negative PAX-8 and positive CD68, favor xanthogranulomatous inflammation. After discussion with patient, she preferred follow up renal mass at OPD.
Abdominal CT follow up 6 months later showed no progressive change of renal tumor. Nevertheless, another CT follow up 4 months later revealed additional renal vein thrombus, favor RCC, cT3aN0. Radical nephroureterectomy was carried out accordingly. Pathology and immunohistochemical stain showed epithelioid eosinophilic neoplasm. Resection margin was clear, but there were many worrisome features including: > 1 mitotic figures per 10hpf, atypical mitotic figures, necrosis, carcinoma-like growth pattern, and invasion of renal vein. Taken together, more aggressive clinical behavior is likely, and long-term follow-up is recommended.
Discussion: Renal EAML can occur sporadically or associate with tuberous sclerosis. Most cases of EAML is benign, approximately one third of EAML cases are characterized by aggressive biological behavior, such as local recurrence after excision, enlarged lymph nodes, extension into the venous system and distant metastases. The standard treatment is partial nephrectomy or radical nephrectomy, depending on tumor size, location, and the need of renal preserving. Some studies have reported that mTOR inhibitors, such as sirolimus or temsirolimus, may represent an improved treatment option for patients with EAML. Therefore, the correct diagnosis of renal EAML can potentially direct clinicians to a more effective therapy, especially in patients with extensive disease.