Guo Aitao, Liu Aijun, Teng Xiaodong
1 Department of Pathology, Chinese PLA General Hospital, Beijing 100853, China ; 2 Department of Pathology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310058, China.
Chin J Cancer Res. 2016 Feb;28(1):107-21. doi: 10.3978/j.issn.1000-9604.2016.02.01.
Inverted lesions in the urinary bladder have been the source of some difficulty in urological pathology. The two common ones are von Brunn's nests and cystitis cystic/cystitis glandularis, which are considered normal variants of urothelium. Apart from them, a number of other rare urothelial lesions with inverted growth pattern occur in the urinary bladder. Some of them are only reactive conditions, just as pseudocarcinomatous hyperplasia. Some are benign tumors, namely inverted papilloma. Whereas others are malignant neoplasms, including inverted papillary urothelial neoplasm of low malignant potential (PUNLMP), non-invasive inverted papillary urothelial carcinoma (low-grade and high-grade), and invasive urothelial carcinoma (inverted, nested and big nested variants). Because of the overlapping morphological features of all the inverted lesions mentioned above, even between high-grade invasive carcinoma and pseudocarcinomatous hyperplasia which are only a kind of reactive conditions, it is very important for the surgical pathologist to recognize and be familiar with these inverted lesions in urinary bladder. In this article, we review these spectrums of inverted lesions of the urinary bladder. Emphasis is placed on histogenesis, morphology, differential diagnosis of these lesions, and the pathologic grading of the non-invasive inverted neoplasms, such as inverted papilloma, inverted PUNLMP, non-invasive inverted papillary urothelial carcinoma with low-grade, and non-invasive inverted papillary urothelial carcinoma with high-grade.
膀胱内翻性病变一直是泌尿外科病理学中的难点。常见的两种是von Brunn巢和囊性膀胱炎/腺性膀胱炎，它们被认为是尿路上皮的正常变异。除此之外，膀胱还会出现一些其他罕见的具有内翻生长模式的尿路上皮病变。其中一些只是反应性病变，如假癌性增生。一些是良性肿瘤，即内翻性乳头状瘤。而其他的则是恶性肿瘤，包括低恶性潜能内翻性乳头状尿路上皮肿瘤（PUNLMP）、非浸润性内翻性乳头状尿路上皮癌（低级别和高级别）以及浸润性尿路上皮癌（内翻型、巢状和大巢状变异型）。由于上述所有内翻性病变在形态学上存在重叠特征，甚至在高级别浸润性癌与仅为一种反应性病变的假癌性增生之间也存在重叠，因此对于外科病理学家来说，识别并熟悉膀胱内这些内翻性病变非常重要。在本文中，我们将对膀胱内翻性病变的各个方面进行综述。重点在于这些病变的组织发生、形态学、鉴别诊断以及非浸润性内翻性肿瘤的病理分级，如内翻性乳头状瘤、内翻性PUNLMP、低级别非浸润性内翻性乳头状尿路上皮癌和高级别非浸润性内翻性乳头状尿路上皮癌。
