A prospective, multicenter analysis of pseudocapsule characteristics: Do all stages of renal cell carcinoma have complete pseudocapsules?

To assess the characteristics of pseudocapsule (PC) in localized renal cell carcinoma (RCC) by analyzing the rates of completeness of PC and pseudocapsular invasion and clinical and pathological risk factors of it.

Between February 2013 and September 2015, data were gathered prospectively from 180 consecutive patients who underwent partial nephrectomy or radical nephrectomy at 3 institutions, and 161 were enrolled. Evaluated factors included age and sex; histologic factors such as tumor diameter, stage, tumor subtype, necrosis, and Fuhrman grade; and clinical factors such as RENAL score; and completeness of PC.

Only 94 tumors (58.4%) were surrounded by a continuous PC completely, 62 (38.5%) were partially surrounded, and 5 (3.1%) had no PC. Overall, 56 PCs (34.8%) were free from invasion, 58 PCs (36.0%) had partial invasion of PC without parenchymal invasion, and 47 PCs (29.2%) had parenchymal invasion. Defining parenchymal invasion as true pseudocapsular invasion, histologic diameter, RCC subtype, and completeness of PC were significant predictors for parenchymal invasion on multivariate analysis (P = 0.006, 0.046, and 0.002, respectively).

Rate of complete PC in RCC is relatively low in this study. The risk factors for pseudocapsular invasion were a histologic diameter greater than 4cm, non-clear cell histology, and an incomplete PC. Surgeons must prepare for the possibility of a positive surgical margin if a tumor has at least one of these risk factors.

Urologic oncology. 2017 Feb 07 [Epub ahead of print]

Seok Cho, Jeong Hyeon Lee, Seung Hyun Jeon, Jinsung Park, Sang Hyub Lee, Chul Hwan Kim, Ji-Youn Sung, Joo Heon Kim, Jong Hyun Pyun, Jeong Gu Lee, Je Jong Kim, Jun Cheon, Sung Gu Kang, Seok Ho Kang

Department of Urology, Korea University School of Medicine, Seoul, Republic of Korea., Department of Pathology, Korea University School of Medicine, Seoul, Republic of Korea., Department of Urology, Kyung Hee University School of Medicine, Seoul, Republic of Korea., Department of Urology, Eulji University Hospital, Eulji University School of Medicine, Daejeon, Republic of Korea., Department of Pathology, Kyung Hee University School of Medicine, Seoul, Republic of Korea., Department of Pathology, Eulji University Hospital, Eulji University School of Medicine, Daejeon, Republic of Korea., Department of Urology, Korea University School of Medicine, Seoul, Republic of Korea. Electronic address: mdksh@korea.ac.kr.