Retrospective Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Nov 6, 2020; 8(21): 5159-5171
Published online Nov 6, 2020. doi: 10.12998/wjcc.v8.i21.5159
Magnetic resonance imaging findings of carcinoma arising from anal fistula: A retrospective study in a single institution
Xin Zhu, Tian-Shu Zhu, Dan-Dan Ye, Shao-Wei Liu
Xin Zhu, Department of Radiology, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing 210029, Jiangsu Province, China
Tian-Shu Zhu, The First Clinical Medical College, Xuzhou Medical University, Xuzhou 221004, Jiangsu Province, China
Dan-Dan Ye, Department of Radiology, Quanzhou Orthopedic-Traumatological Hospital, Quanzhou 362000, Fujian Province, China
Shao-Wei Liu, Department of Radiology, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing 210029, Jiangsu Province, China
Author contributions: Zhu X and Zhu TS contributed equally to this work as first authors; all authors have made an intellectual contribution to the manuscript and approved the submission.
Institutional review board statement: The study was reviewed and approved by the Ethics Committee of The Affiliated Hospital of Nanjing University of Chinese Medicine Nanjing, Jiangsu Province, China.
Conflict-of-interest statement: The authors declare that they have no conflict of interest.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Xin Zhu, MD, Doctor, Department of Radiology, The Affiliated Hospital of Nanjing University of Chinese Medicine, No. 155 Hanzhong Road, Nanjing 210029, Jiangsu Province, China. zhuxin-njcm@njucm.edu.cn
Received: July 19, 2020
Peer-review started: July 6, 2020
First decision: August 8, 2020
Revised: August 18, 2020
Accepted: September 17, 2020
Article in press: September 17, 2020
Published online: November 6, 2020
Processing time: 109 Days and 17.2 Hours
Abstract
BACKGROUND

Magnetic resonance imaging (MRI) is currently the standard investigation for suspected perianal diseases. Carcinoma arising from anal fistula is very rare, and early diagnosis is often difficult.

AIM

To describe and summarize the MRI findings of carcinoma arising from anal fistula.

METHODS

In this retrospective study, records of ten patients diagnosed with carcinoma arising from anal fistula and confirmed by surgery (n = 7) or biopsy (n = 3) between June 2006 and August 2018 were analyzed. All patients underwent preoperative pelvic MRI. Morphologic features, signal characteristics, fistula between the mass and the anus, contrast enhancement of mass, signal and enhancement of peritumoral areas, and regional lymphadenopathy were assessed.

RESULTS

All ten tumors were solitary (8 mucinous adenocarcinomas and 2 adenocarcinomas). The maximum diameter of the tumors ranged from 3.4 cm to 12.4 cm (median: 4.15 cm; mean: 5.68 cm). Eight patients had a fistula between the mass and the anus. Contrast enhancement of the peritumoral areas was noted in three (3/5) patients. Perirectal or inguinal lymphadenopathy was noted in seven patients. Most lesions of mucinous adenocarcinoma were multiloculated and cauliflower-like, with a thin capsule and focally unclear boundary. They were markedly hyperintense on fat-suppressed T2WI, slightly hyperintense with focal hyperintensity on diffusion-weighted imaging (DWI), and hyperintense with focal hypointensity on apparent diffusion coefficient (ADC) map, with progressive mesh-like contrast enhancement. Adenocarcinomas had an infiltrative margin without a capsule and appeared heterogeneously hyperintense or slightly hyperintense on fat-suppressed T2WI, hyperintense on DWI, and hypointense on ADC map, with persistent heterogeneous enhancement.

CONCLUSION

Our study highlighted several characteristic and potentially helpful MRI findings to diagnose carcinomas arising from anal fistula.

Keywords: Anal fistula; Carcinoma; Magnetic resonance imaging; Morphologic features; Signal characteristics; Differential diagnosis

Core Tip: Magnetic resonance imaging (MRI) is currently the standard investigation for suspected perianal diseases. Carcinoma arising from anal fistula is very rare, and early diagnosis is often difficult. We aimed to describe and summarize the MRI findings of this entity.