Renal clear cell carcinoma undergoing cystic change: A cases report and review of the literature

Introduction: We presented a case diagnosed the renal clear cell carcinoma undergoing cystic change (RCCCC) with detailed clinical data. Along with literature review, we aimed to investigate clinical diagnosis and treatment of RCCCC and explore the differential diagnosis of RCCCC and multilocular cystic renal cell carcinoma (MCRCC). Case presentation: The patient was diagnosed with a right renal cyst after physical examination, which was misdiagnosed as a renal cyst by imaging examination. Intraoperative surgical treatment was performed to remove the roof and decompress the renal cyst. Rapid pathology revealed MCRCC with low malignant potential during laparoscopic right renal cyst decompression. Radical nephrectomy was performed with the family's signature. The postoperative pathological diagnosis was clear cell carcinoma cystic lesion of kidney (RCCCC). No recurrence or metastasis during 1 year follow-up. Clinical discussion: RCCCC cases were similar to classical clear cell renal carcinoma. Radical nephrectomy should be avoided in patients with MCRCC, and radical nephrectomy should be chosen in patients with RCCCC, with postoperative and close follow-up. Unroofing decompression of renal cyst was performed during the operation, and the risk of tumor implantation and metastasis was worried after the operation. The patient agreed to receive eight cycles of immune checkpoint inhibitor therapy after surgery. Adrenal insufficiency occurred after 8 cycles of immune checkpoint inhibitor therapy(ICIs), then the immunotherapy was discontinued. Conclusion: RCCCC is a rare and special type of renal clear cell carcinoma, and its prognosis is the same as that of renal clear cell carcinoma. The preoperative diagnosis of RCCCC mainly depends on imaging examination (CT or B-ultrasound). The early differential diagnosis from multilocular cystic renal cell carcinoma is difficult, and the diagnosis usually depends on postoperative pathological diagnosis.