Pathological features of clinical T1b renal cell carcinoma

Abstract

Objective To investigate the pathological characters of clinical T1b (4<diameter≤7 cm) renal cell carcinoma and provide reference basis for the nephron sparing surgery (NSS). Methods From January 2002 to December 2014, the pathological features of clinical T1b renal cell carcinoma were studied in 710 cases, including 505 male cases and 205 female cases. The mean age was 58 years old, ranged from 26 to 88 years old. The location of tumor included 377 in left side and 383 in right side. In the recorded 372 cases, the accurate site of tumor included 137 in upper portion, 96 in middle portion and 139 in lower portion. The initial symptom included hematuria in 103 cases, back pain in 62 cases, hematuria accompanied with back pain in 34 cases and asymptom in 511 cases. The diameter of tumor ranged from 4.0 to 7.0 cm, mean 5.4 cm. We analyzed pathological features, Fuhrman grades, histologic subtype, tumor metastasis, perirenal fat invasion and vein tumor thrombosis in all patients. Results The proportions of the clear cell, papillary, chromophobe, unclassified and mixed cell histologic subtype were 75.8% (538/710), 5.1% (36/710), 4.6% (33/710), 1.1% (8/710) and 13.4% (95/710), respectively. The proportions of hemorrhage, necrosis, cystic degeneration and fibrosis were 51.0% (362/710), 30.1% (214/710), 35.4% (251/710) and 7.8% (55/710), respectively. The rates of perirenal fat invasion and vein tumor thrombosis were 4.1% (29/710) and 3.1% (22/710). Among the 710 clinical T1b renal cell carcinoma, 144 (20.3%) were Fuhrman gradeⅠ, 513 (72.3%) were grade Ⅱ, 43 (6.1%) were grade Ⅲ, 10 (1.4%) were grade Ⅳ. In 657 cases with low Fuhrman grade(Ⅰ/Ⅱ), 17 cases were noticed perirenal fat invasion.In 53 cases with high Fuhrman grade (Ⅲ/Ⅳ), 10 cases were noticed perirenal fat invasion. The analysis showed that high Fuhrman grading was concerned with the perirenal fat invasion. Conclusions Clinical T1b renal cell carcinoma has obvious heterogeneity in its biological behavior. Most of them has characters of high differentiation, low malignant tendency and good biological behavior. Rare carcinoma exhibits the aggressive character or early distant metastasis. During the nephron sparing surgery, perirenal fat should be removed and perform pathological examination. Vein tumor thrombosis should be bolt out and radical nephrectomy is recommended at the same time. Key words: Carcinoma, renal cell; Pathology; Nephron sparing surgery