Roquero Leonardo, Kryvenko Oleksandr N, Gupta Nilesh S, Lee Min W
Department of Pathology, Henry Ford Health System, Detroit, MI, USA
Departments of Pathology and Urology, University of Miami Miller School of Medicine, Miami, FL, USA.
Int J Surg Pathol. 2015 Aug;23(5):359-63. doi: 10.1177/1066896915579198. Epub 2015 Apr 2.
Pseudocapsule in renal cell carcinoma (RCC) has been described but little is known about its prevalence and extent. Pseudocapsule was analyzed in 105 RCCs (44 clear cell, 44 chromophobe, 17 papillary). Pseudocapsule was graded as follows: grade 1, thickness comparable to adjacent muscular arteries; grade 2, thickness more than twice the diameter of adjacent muscular arteries; grade 3, grade 2 findings with vasculopathy. Tumor size, tumor regression, and International Society of Urologic Pathology (ISUP) nucleolar grade were recorded. Cases with grade 3 pseudocapsule were stained with elastic silver stain, Alcian blue, smooth muscle actin, and CD31. More clear cell RCCs had pseudocapsule (89%, 39/44) than chromophobe (30%, 13/44) and papillary (35%, 6/17). Average tumor size with pseudocapsule was 3.9 cm; average tumor size without pseudocapsule was 3.8 cm (P = .77). Grade 2 pseudocapsule was common in clear cell RCC (56%, 22/39). Chromophobe and papillary RCC had grade 1 pseudocapsule in 77% (10/13) and 83% (5/6) of cases. Grade 3 pseudocapsule was only seen in clear cell RCC (10%, 4/39). No correlation was noted between degenerative tumor changes, tumor size, ISUP nucleolar grade, and presence and grade of pseudocapsule. Smooth muscle actin and CD31 showed abundant smooth muscle component and rich vasculature within the pseudocapsule. Arterial elastic membrane disruption and/or fibrointimal mucin deposits were present in grade 3 pseudocapsule. Thus, pseudocapsule is rather characteristic and more prominent in clear cell, less frequent in chromophobe, and rare in papillary RCC. Its presence may be evaluated radiologically or in biopsy specimens with scant tumor fragments.
肾细胞癌（RCC）中的假包膜已有描述，但对其发生率和范围了解甚少。对105例肾细胞癌（44例透明细胞癌、44例嫌色细胞癌、17例乳头状癌）进行了假包膜分析。假包膜分级如下：1级，厚度与相邻肌性动脉相当；2级，厚度超过相邻肌性动脉直径的两倍；3级，伴有血管病变的2级表现。记录肿瘤大小、肿瘤消退情况以及国际泌尿病理学会（ISUP）核仁分级。对3级假包膜的病例进行弹性银染、阿尔辛蓝、平滑肌肌动蛋白和CD31染色。透明细胞肾细胞癌有假包膜的比例（89%，39/44）高于嫌色细胞癌（30%，13/44）和乳头状癌（35%，6/17）。有假包膜的肿瘤平均大小为3.9 cm；无假包膜的肿瘤平均大小为3.8 cm（P = 0.77）。2级假包膜在透明细胞肾细胞癌中常见（56%，22/39）。嫌色细胞癌和乳头状肾细胞癌分别有77%（10/13）和83%（5/6）的病例为1级假包膜。3级假包膜仅见于透明细胞肾细胞癌（10%，4/39）。未发现肿瘤退行性改变、肿瘤大小、ISUP核仁分级与假包膜的存在及分级之间存在相关性。平滑肌肌动蛋白和CD31显示假包膜内有丰富的平滑肌成分和丰富的血管。3级假包膜存在动脉弹性膜破坏和/或纤维内膜粘蛋白沉积。因此，假包膜具有一定特征性，在透明细胞癌中更突出，在嫌色细胞癌中较少见，在乳头状肾细胞癌中罕见。其存在可通过影像学评估或在肿瘤碎片较少的活检标本中评估。
