[Metastatic renal cell carcinoma: a clinicopathological analysis of 196 cases]

Objective: To analyze the clinico pathological features, differential diagnosis and prognosis of metastatic renal cell carcinomas. Methods: The clinical data, histology, immunophenotype and follow-up data of 196 patients with metastatic renal cell carcinoma diagnosed from 1994 to 2017 at the Department of Pathology, Changhai Hospital, Naval Military Medical University, Shanghai, China were analyzed retrospectively. Results: There were 142 males and 54 females, with a median age of 61 years. The top three metastatic sites for the 196 cases of metastatic renal cell carcinoma were lung (31.1%, 61/196), bone (29.1%, 57/196) and digestive system (19.4%, 38/196). Among the pathological subtypes of metastasis, the proportion of clear cell renal cell carcinoma was 94.4% (185/196) and that of type II papillary renal cell carcinoma was 3.6% (7/196). The TFE3 translocated renal cell carcinoma and congestive tubular carcinoma were rare, with 3 cases and 1 case, respectively. CK, vimentin, CAⅨ and CD10 were expressed in all metastatic clear cell renal cell carcinomas. CK7, CD10 and P504s were expressed in papillary renal cell carcinomas. TFE3 was expressed in TFE3 translocated renal cell carcinoma. The collecting duct carcinoma was positive for HCK. Conclusions: Lung metastasis and bone metastasis are still the most frequent metastatic sites of renal cell carcinoma. Five years after primary lesion resection may be the high risk time for metastasis. Most of the metastases are solitary when they are first identified. To better diagnose and identify the renal origin of a metastatic renal cell carcinoma, one should consider morphological characteristics, clinical history information of the metastasis and the combined immunohistochemistry of CK, vimentin, CD10, CK7, TFE3, PAX2 and PAX8.