Renshaw A A, Zhang H, Corless C L, Fletcher J A, Pins M R
Department of Pathology, Brigham & Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
Am J Surg Pathol. 1997 Oct;21(10):1203-9. doi: 10.1097/00000478-199710000-00011.
Papillary renal cell carcinomas (RCCs) traditionally have been defined histologically as tumors with at least 50% true papillae. However, these tumors also have characteristic immunohistochemical and genetic features that separate them from other RCCs. We identified six tumors composed of solid sheets of cells without true papillae but that otherwise resembled papillary RCCs, which we feel represent solid variants of papillary RCCs. All six tumors were primary lesions of the kidney, all were strongly reactive for epithelial membrane antigen, cytokeratin 7, and callus keratin, and all were negative for the high molecular weight keratin antibody 34BE12. Four of four tumors tested showed trisomies for chromosome 7, chromosome 17, or both by either cytogenetic analysis or fluorescence in situ hybridization. Four cases were composed of solid sheets of cells containing distinct micronodules that in some cases resembled abortive papillae. The cells composing the micronodules had abundant eosinophilic cytoplasm, open chromatin, and in some cases prominent nucleoli. The intervening cells had similar nuclei, but the amount of cytoplasm was variable. In three of these micronodular cases, multiple tumors diffusely replaced the kidney; in the fourth case two typical clear cell RCCs and a typical papillary RCC were also present in the same kidney, but the micronodular tumor was unifocal. The two remaining cases were solitary tumors consisting of solid sheets of cells forming ill-defined tubules. These cells had scant clear cytoplasm and small round to elongate nuclei with occasional nuclear grooves but only rare small nucleoli. Limited follow-up has shown no evidence of disease in any patient thus far. The differential diagnosis includes "renal adenoma," renal adenomatosis, metanephric adenoma, and clear/granular cell RCC. We conclude that solid variants of papillary RCCs lack true papillae but have characteristic histologic, immunohistochemical, and genetic features.
传统上，乳头状肾细胞癌（RCC）在组织学上被定义为至少50%为真性乳头的肿瘤。然而，这些肿瘤也具有特征性的免疫组化和基因特征，使其与其他肾细胞癌区分开来。我们识别出6例肿瘤，其由无真性乳头的实性细胞片组成，但在其他方面类似于乳头状肾细胞癌，我们认为这些肿瘤代表乳头状肾细胞癌的实性变体。所有6例肿瘤均为肾脏原发性病变，均对上皮膜抗原、细胞角蛋白7和角蛋白呈强阳性反应，且均对高分子量角蛋白抗体34BE12呈阴性。通过细胞遗传学分析或荧光原位杂交检测，4例检测的肿瘤中有4例显示7号染色体、17号染色体三体或两者均三体。4例由含有不同微结节的实性细胞片组成，在某些情况下这些微结节类似于发育不全的乳头。构成微结节的细胞具有丰富的嗜酸性细胞质、开放染色质，在某些情况下有明显核仁。其间的细胞有相似的细胞核，但细胞质的量各不相同。在这些微结节性病例中的3例中，多个肿瘤弥漫性取代肾脏；在第4例中，同一肾脏中还存在2例典型的透明细胞肾细胞癌和1例典型的乳头状肾细胞癌，但微结节性肿瘤为单灶性。其余2例为孤立性肿瘤，由形成边界不清小管状的实性细胞片组成。这些细胞有少量清亮细胞质和小圆形至细长形细胞核，偶尔有核沟，但仅有罕见的小核仁。有限的随访显示，迄今为止任何患者均无疾病证据。鉴别诊断包括“肾腺瘤”、肾腺瘤病、后肾腺瘤以及透明/颗粒细胞肾细胞癌。我们得出结论，乳头状肾细胞癌的实性变体缺乏真性乳头，但具有特征性的组织学、免疫组化和基因特征。
