Case Report
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Mar 6, 2019; 7(5): 684-690
Published online Mar 6, 2019. doi: 10.12998/wjcc.v7.i5.684
Melanotic Xp11-associated tumor of the sigmoid colon: A case report
Gang Wang, Gang-Gang Li, Sheng-Mao Zhu, Bao-Jia Cai, Peng-Jie Yu, Cheng-Wu Zhang
Gang Wang, the Graduate School of Qinghai University, Xining 810016, Qinghai Province, China
Gang-Gang Li, Sheng-Mao Zhu, Bao-Jia Cai, Peng-Jie Yu, Cheng-Wu Zhang, Department of Gastrointestinal Surgery, Affiliated Hospital of Qinghai University, Xining 810000, Qinghai Province, China
Author contributions: Li GG and Zhu SM designed the study; Zhang CW, Cai BJ, and Yu PJ performed the operation; Wang G wrote the paper; all authors read and approved the final manuscript.
Supported by The Key Research & Development and Transformation Project of Qinghai Province for 2018 (No. 2018-SF-113).
Informed consent statement: Informed consent was obtained from the patient for this publication.
Conflict-of-interest statement: The authors declare that they have no competing interests.
CARE Checklist (2016) statement: The guidelines of the “CARE Checklist - 2016: Information for writing a case report” have been adopted.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (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: Cheng-Wu Zhang, MD, Chief Doctor, Professor, Department of Gastrointestinal Surgery, Affiliated Hospital of Qinghai University, No. 29, Tongren Road, Xining 810000, Qinghai Province, China. 861072284@qq.com
Telephone: +86-153-4973630
Received: November 16, 2018
Peer-review started: November 16, 2018
First decision: December 9, 2018
Revised: December 30, 2018
Accepted: January 30, 2019
Article in press: January 30, 2019
Published online: March 6, 2019
Abstract
BACKGROUND

Melanotic Xp11-associated tumors are rare mesenchymal-derived tumors. So far, most primary melanotic Xp11-associated tumors have been reported in the kidney, and reports of this tumor in the gastrointestinal tract are rare.

CASE SUMMARY

Here we describe the case of a 25-year-old woman who presented with a melanotic Xp11-associated tumor in the sigmoid colon. Colonoscopy revealed a large mucosal bulge in the sigmoid colon, approximately 32 cm inside the anus. The surface was rough with local erosion. The tumor was brittle on biopsy and bled easily. Computed tomography revealed thickening of the rectal wall with edema. Postoperative pathology indicated the likelihood of a perivascular epithelioid cell tumor. Histologically, the tumor comprised plump epithelioid cells with abundant clear to lightly eosinophilic cytoplasm and round nuclei arranged in an alveolar or trabecular pattern. The tumor cells were strongly positive for HMB-45, Melan-A, Cathepsin K, and TFE3 but negative for vimentin, smooth muscle actin, S100 protein, CD10, CK20, and desmin. The tumor cells had a low Ki-67 labeling index (approximately 2%). Fluorescence in situ hybridization revealed TFE3 fracture. Based on these histologic and immunohistochemical features, a diagnosis of melanotic Xp11-associated tumor of the sigmoid colon was made.

CONCLUSION

In summary, we report the clinicopathological features of a primary tumor that is extremely rare in the sigmoid colon and review the clinicopathological characteristics of melanotic Xp11-associated tumors, compatible with the very rare tumor termed “melanotic Xp11 translocation renal cancer” in all aspects.

Keywords: Melanotic Xp11-associated tumor, Perivascular epithelioid cell tumor, Melan-A, Sigmoid colon, Case report

Core tip: Melanotic Xp11-associated tumors can occur at all ages; children and young adults are particularly prone whereas it is rare in middle-aged and elderly individuals. So far, most primary melanotic Xp11-associated tumors have been reported in the kidney, and reports of this tumor in the gastrointestinal tract are rare. Therefore, data regarding the clinical features and biologic behavior of melanotic Xp11-associated tumors are limited.