Clinical and pathological analysis of collecting duct carcinoma of the kidney

Objective To analyze the clinical and pathological features of collecting duct carcinoma (CDC) of the kidney. Methods 11 patients with CDC were analyzed,among which 6 were males and 5 were females.Their age ranged from 22 to 67 years old with a mean age of 55.4 cases were found by routine health examination,4 cases were presented with gross hematuria and 3 cases had flank or abdomen pain.The CT scan showed an unclear boundary mass in kidney,with tumor sizes from 2.1 to 8.5 cm ( mean 5.6 cm).Only medullary involvement was present on CT in 3 cases,Medullary and cortical involvement in 5 cases,Medullary and pelvic involvement in 2 cases,and all involvement in 1 case.Infiltrative lesion has expanded kidney but maintains reniform contour.Contrast-enhanced CT scan showed lesion mild to moderate enhancement compared with surrounding parenchyma. Results Radical nephrectomy was performed in 8 cases and palliative nephrectomy in 3 cases.All patients were finally diagnosed by pathology.Grossly,the tumor is often appears gray or white.In HE staining,tumor showed prominent tubular or tubulaopapillary structures with desmoplasia and inflammatory reaction.Occasionally,some tumor cells take on a hobnail appearance.Immunohistochemical examination showed UEA-1 positive in all cases,EMA positive in 9 cases,PNA positive in 8 cases,and HMW-CK positive in 7 cases.Only 2 patients showed positive CD10.7 patients died within 6 to 47 months (mean 12.5 months),2 survived with tumor free for 9 months and 8 years respectively,one lost of follow-up,and one patient with distant metastasis is receiving postoperative chemotherapy. Conclusions Collecting duct carcinoma of the kidney is a rare histological type of renal cell carcinoma,whose final diagnosis depends on histopathological examination.Rapid progression,highly malignant,poor prognosis are the characteristics of this disease. Key words: Kidney neoplasms;  Collecting duct;  Carcinoma