An 83-year-old man complained of repeated hematochezia for 3 months. Noother medical history was reported except for the percutaneous needle aspiration of left renal cyst 10 years ago. Colonoscopy revealed a 25-mm protruded lesion with central ulcer formation at the descending colon (Figure 1A). Massive bleeding occurredduring for cepsbiopsy (Figure1B), which was temporary managed by the clips. The initial pathologic result only indicated inflammation without evidence of malignancy. Abdominal enhancedcomputedtomography(CT)revealedaneoplasticlesionin the descending colon, involving adjacent left kidney (Figure 1C). The laparoscopic surgery was indicated for the management of massive bleeding. However, the histopathological findings showed renalcellcarcinoma(RCC)directlyinvadedfromcolonicserosato propriamusculariswithimmunohistochemicalstainingexpressing PAX-8,whcihindicatedclearcellrenalcellcarcinoma(ccRCC) .(Figure2A,H&E,orig.mag.×40;Figure2B,H&E,orig.mag. ×200; Figure 2C, IHC, orig. mag. ×200;). Renal cell carcinoma (RCC),locatedintheretroperitonealcavity,usuallymetastasizeto lymph nodes, lungs, bones, livers and brains [1], however, due to theanatomicseparation,themetastasisfromRCCtocolonorprimarycolontumortokidneywereonlyreportedinfewwidespread cases, while direct invasion rarely occurred [2,3]. A case report observedthatclipsmigratedtothedescendingcolonafterleftkid- ney nephrectomy, possibly caused by the postoperative repairing process [4]. In the present case, the postoperative histological observationofthetumorrevealedcloseadhesionsbetweeninvolved leftkidneyandcolonicwall,whichimpliedtheraresiteofcolonic metastasis might occur as the result of the previous interventionofleftrenalcyst.Therefore,whenacoloniclesioninvaded nearby kidneys, the possibility of colonic metastasis of RCC needs to be considered, especiallyin the patientswith history of renal disease or interventions.
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LiY. AProtrudedLeisionwithHemorrhageofUnexpectedHistologicalFindings . Annals of Clinical and Medical Case Reports 2021