From the Department of Radiology, University of Texas Health Science Center, 6431 Fannin St, MSB 2.130, Houston, TX 77030 (V.R.S.); Department of Radiology, Mayo Clinic, Scottsdale, Ariz (C.O.M., A.K.H.); Department of Radiology, University of Texas MD Anderson Cancer Center, Houston, Tex (A.M.A., M.E., K.M.E.); Department of Radiology, University of Texas Health Science Center, San Antonio, Tex (V.S.K.); Department of Radiology, MetroHealth Medical Center, Cleveland, Ohio (W.C.B.); Department of Radiology, University of Ottawa, Ottawa, Ontario, Canada (A.K.); and Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (C.L.S.).
Radiographics. 2016 Sep-Oct;36(5):1339-53. doi: 10.1148/rg.2016150209.
Tumors and tumorlike conditions of the anus and perianal region originate from the anal canal and anal margin or result from direct extension of tumors from adjacent organs. The anatomy of the anal canal is complex, and its different histologic characteristics can lead to diverse pathologic conditions. The anal canal extends from the anorectal junction to the anal verge. The World Health Organization classification of anal canal tumors includes (a) anal intraepithelial neoplasia, the precursor of squamous cell carcinoma (SCC), and (b) invasive tumors. Invasive tumors are further classified on the basis of cell type as epithelial tumors (SCC, adenocarcinoma, mucinous adenocarcinoma, small cell carcinoma, and undifferentiated carcinoma), nonepithelial tumors, carcinoid tumors, melanoma, and secondary tumors (direct spread from rectal, cervical, or prostate carcinoma). The anal margin, or perianal skin, lies outside the anal verge and encompasses a radius of 5 cm from the anal verge. Tumors in the anal margin are classified according to the World Health Organization classification of skin tumors. Anal margin tumors include SCC, anal intraepithelial neoplasia, also known as Bowen disease, adenocarcinoma and its precursor Paget disease, basal cell carcinoma, and verrucous carcinoma (Buschke-Löwenstein tumor), which is a rare variant of SCC. Imaging plays an important role in the evaluation, staging, and follow-up of patients with anal and perianal tumors. However, because of the overlap in imaging features among these diverse entities, a definitive diagnosis is best established at histopathologic examination. Nevertheless, familiarity with the pathogenesis, imaging features, and treatment of these tumors can aid radiologic diagnosis and guide appropriate patient treatment. (©)RSNA, 2016.
肛门和肛周区域的肿瘤和肿瘤样病变源自肛管和肛门边缘，或由相邻器官的肿瘤直接延伸所致。肛管的解剖结构复杂，其不同的组织学特征可导致不同的病理状况。肛管从直肠肛门交界延伸至肛门缘。世界卫生组织（WHO）对肛管肿瘤的分类包括（a）肛门上皮内瘤变，是鳞状细胞癌（SCC）的前身，和（b）浸润性肿瘤。浸润性肿瘤进一步根据细胞类型分为上皮性肿瘤（SCC、腺癌、黏液腺癌、小细胞癌和未分化癌）、非上皮性肿瘤、类癌肿瘤、黑色素瘤和继发性肿瘤（来自直肠、宫颈或前列腺癌的直接扩散）。肛门边缘或肛周皮肤位于肛门缘之外，涵盖距肛门缘 5cm 的半径范围。肛门边缘的肿瘤根据 WHO 皮肤肿瘤分类进行分类。肛门边缘肿瘤包括 SCC、肛门上皮内瘤变，又称 Bowen 病、腺癌及其前驱 Paget 病、基底细胞癌和疣状癌（Buschke-Löwenstein 肿瘤），后者是 SCC 的罕见变异型。影像学在评估、分期和随访肛门和肛周肿瘤患者中发挥着重要作用。然而，由于这些不同实体之间的影像学特征存在重叠，因此最好通过组织病理学检查来建立明确的诊断。尽管如此，熟悉这些肿瘤的发病机制、影像学特征和治疗方法可以有助于放射诊断并指导患者的适当治疗。（©）RSNA，2016 年。
