A healthy 45-year-old woman underwent a right nephrectomy in order to donate the kidney to her brother. The preoperative evaluation included a complete physical examination, complete blood cell count, liver function tests, serum creatinine measurement, serum electrolytes tests, routine clotting studies, hepatitis serologies, VDRL testing, HIV testing, urinalysis, creatinine clearance and quantitative urinary protein tests, intravenous pyelography, and renal angiography. The physical examination and all tests and radiologic evaluations were normal. The right kidney was chosen for donation because the angiogram revealed double left renal arteries but only a single right renal artery. During surgery, a 1-cm multicystic lesion was enucleated from the right lower pole of the kidney with the back of a knife handle and sent for frozen section examination (Figure 1). After the lesion was reported to be a benign mesenchymal tumor, the base of the lesion was fulgurated, and the transplantation to the patient's 33-year-old brother proceeded without complication.
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Low-power microscopy shows a multicystic renal lesion (hematoxylin-eosin stain, x40).
Unfortunately, permanent sections of the 1-cm lesion showed nuclear grade 1 clear cells lining the cysts and infiltrating the septae between cysts (Figure 2). A dense, fibrous capsule separated the lesion from normal parenchyma. The margins were negative, and no clear cells were identified in the surrounding capsule. Within the lesion, focal areas of necrosis and calcification were identified. The final diagnosis was multilocular cystic renal cell carcinoma (MCRCC).
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High-power microscopy demonstrates a cyst lined by nuclear grade 1 clear cells (hematoxylin-eosin stain, x200).
What do you recommend?
No further follow-up.
Careful surveillance.
Retransplantation when feasible.
Immediate transplant nephrectomy.