非活體移植腎偶見上皮樣血管平滑肌脂肪瘤 - 病例報告

王毓婷¹ 、李明哲²、董劭偉¹ 、陳至亨¹、鄒凱亦¹

¹台北醫學大學附設雙和醫院泌尿科,  ²台北醫學大學附設雙和醫院一般外科

Incidental Epithelioid Angiomyolipoma in a Deceased Donor Kidney : a Case Report

Yu-Ting Wang¹ Ming-Che Lee² , Shao-Wei Dong¹ , Chih-Heng Chen¹, Kai-Yi Tzou¹

1Department of Urology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, ²Department of General Surgery, Shuang Ho Hospital, Taipei Medical University, New Taipei City

Introduction

A deceased donor kidney with an incidentaloma carries the risk of transmitting malignancy to the recipient. Partial nephrectomy (PN) before grafting is considered a safe approach as it does not increase surgery-related complications or post-transplant cancer recurrence. However, specific tumors with an unknown level of transmission potential require more rigorous clinical judgment and a more comprehensive follow-up plan. Through this case report and literature review, we aimed to evaluate the safety of performing partial nephrectomy on a graft that contained epithelioid angiomyolipoma (EAML), a tumor that carries an unclear malignant potential due to its rarity.

Case report

A 52-year-old female patient had a medical history of poorly controlled hyperlipidemia and end stage renal disease. After being on continuous ambulatory peritoneal dialysis (CAPD) for eight years, she was admitted to receive a kidney from a deceased donor, a 64-year-old female with schizophrenia, who suffered cardiac arrest as a result of aspiration pneumonia. Preoperative CT of the donor revealed an incidentaloma over the kidney of interest. The lesion was 2 cm in size and demonstrated an early arterial enhancement with an early washout pattern. Despite the lesion suggested by imaging, kidney procurement was performed, and PN was carried out during the back-table preparation for both diagnostic and therapeutic purposes. While awaiting frozen section analysis, the collecting system defect was attended using 5-0 polydioxanone (PDS), and the renal cortex was closed with horizontal mattresses over a cellulose Teflon Pledget using 2-0 Prolene. The frozen section yielded a diagnosis of EAML, and then the transplant proceeded after 10 hours and 35 minutes of cold ischemia time. Postoperative sonogram showed fair graft perfusion. However, delayed graft function had the patient returned to CAPD the next day after surgery. Along the postoperative course, urine output and serum creatinine level made gradual improvement. In addition, no urinary tract infection nor urinary leakage was noticed. At last, CAPD was terminated on postoperative day 14. The patient was eventually discharged under improved and relatively stable condition. At the latest outpatient clinic visit, her serum creatinine level and urine output were found to be 1.5 mg/dL and 2200 ml, respectively.

Discussion

The ongoing organ shortage necessitates the assessment of all potential donors, including those with malignant diseases. For renal grafts containing suspicious masses, evidence suggests that performing partial nephrectomy does not significantly increase surgery-related complications or cancer recurrence for the recipient. According to the consensus made by the United Network for Organ Sharing (UNOS), the risk of donor-transmitted malignancy is 0% for benign tumors, whereas the risk is less than 1% for renal cell carcinoma smaller than 2.5 cm. In these cases, transplant with the grafts is usually recommended.

We describe a case of deceased donor kidney transplant with a graft that carries EAML, a rare subtype of AML characterized by the predominance of epithelioid cells rather than adipose tissue. Unlike benign AML, approximately 21 to 30% of EAML cases exhibited local recurrence, invasion, and/or distant metastasis. Predictive factors for malignant behavior include tumor size >9 cm, renal vein invasion, ≥ 70% atypical epithelioid cells, ≥ 2 mitotic figures per 10 high-power fields, atypical mitotic figures, and the presence of tumor necrosis. Partial or radical nephrectomy remains the primary treatment for EAML, and clinical studies have shown that mTOR inhibitors may be effective in the cases of recurrent or metastatic disease. However, there is no consensus on the optimal follow-up strategy. Considering the recipient's vulnerable renal function, sonography or CT scan without contrast at regular intervals might be more appropriate.

Conclusion