Discussion On The Differential Diagnosis Of Renal Cell Carcinoma With Papillary Structure

Objective:This study aimed to detect the clinicopathological characteristics and immunophenotype of papillary renal cell carcinoma,clear cell papillary renal cell carcinoma and Xp11 translocation RCCs.Methods:We collected the surgical cases of renal cell carcinoma in Cancer Hospital Chinese Academy of Medical Sciences from January 2015 to December 2019 and selected pathologically-confirmed cases of papillary renal cell carcinoma,clear cell papillary renal cell carcinoma and Xp11 translocation RCCs.Clinical statistics were recorded and FISH analysis were conducted for Xp11 translocation RCCs cases.Pathological sections were reviewed and we observed the cell arrangement,nuclear morphology and stromal changes of those tumors under microscope.We chose typical sections for tissue microarrays and then for immunohistochemical staining.The immunohistochemical antibodies include Cathepsin K、GLUT1、CAⅨ、GATA3、P504S、PAX8、CD10、CK7、RCCm、AE1/AE3、EMA、CK34βE12、CK18、TFE3、HMB45 and Ki-67.We analyzed the results using statistical software SPSS 19.0 to obtain an antibody group for the differential diagnosis for the three renal cell carcinomas with papillary structure we mentioned above.Results:A total of 99 cases were included ranging from 18 to 88 years old(mean 56 years)with male to female ratio of 2:1.The tumor size ranged from 0.8～17cm(mean 4.9cm).Patients with Xp11 translocation RCCs were generally younger than those with papillary renal cell carcinoma and clear cell papillary renal cell carcinoma(P<0.05),and the latter two tend to occur to men(P<0.05).Besides,the tumor size of clear cell papillary renal cell carcinoma were significantly smaller than that of the other two(P<0.05).Morphologically,the existence of necrosis and psammoma bodies is meaningful in the differential diagnosis.The arrangement of nuclei in clear cell papillary renal cell carcinoma is characteristic of‘piano key’ pattern or resembles the endometrium in secretory phase(44%,7/16).And clusters of hyalinized globules can be observed in Xp11 translocation RCCs(29%,2/7).Necrosis is often seen in Xp11 translocation RCCs(71%,5/7;43%,3/7)and papillary renal cell carcinoma(53%,40/76;36%,27/76),which is less common in clear cell papillary renal cell carcinoma(6%,1/16;12%,2/16).Psammoma bodies are most commonly seen in Xp11 translocation RCCs(100%,7/7).They can present in papillary renal cell carcinoma(8%,7/76)and are absent in clear cell papillary renal cell carcinoma(0/16).According to statistical analysis of immunophenotype,we found out that the following antibodies including CK18、CK7、AE1/AE3、EMA、CA9、HMB45、P504S and PAX8,are useful in distinguishing the three tumors from each other with positive rate of 74%、56%、82%、71%、45%、16%、77%and 86%respectively.There is significant difference in the expression of those antibodies in different tumors(P<0.05).The ROC(receiver-operator characteristic curve)for different types of tumors was made and the AUC(area under the curve)was calculated for each antibody.Then we obtained the group of CK7、CAIX、P504S and HMB45 for differential diagnosis.The AUC of this panel for the diagnosis of papillary renal cell carcinoma,clear cell papillary renal cell carcinoma and Xp11 translocation RCCs are 0.590(95%CI,0.526～0.653)、0.781(95%CI,0.655～0.906)and 0.692(95%CI,0.499～0.896)respectively.Conclusion:Among the three tumors we collected,clear cell papillary renal cell carcinoma and papillary renal cell carcinoma have a preference for middle-aged or old male while Xp11 translocation RCCs occurs to young female.Clear cell papillary renal cell carcinoma exhibits the smallest diameters in tumor size.Microscopically,necrosis and psammoma bodies are frequent in papillary renal cell carcinoma and Xp11 translocation RCCs.If there are problems in specific diagnosis according to clinical and histological features,immunohistochemical panel including CK7、CAⅨ、P504S and HMB45 may help.