Case Report
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jun 26, 2021; 9(18): 4789-4796
Published online Jun 26, 2021. doi: 10.12998/wjcc.v9.i18.4789
Collision carcinoma of the rectum involving neuroendocrine carcinoma and adenocarcinoma: A case report
Xing Zhao, Gang Zhang, Chun-Hui Li
Xing Zhao, Chun-Hui Li, Department of Pathology, The Affiliated Hospital of Chengde Medical University, Chengde 067000, Hebei Province, China
Gang Zhang, Department of General Surgery IV, Baoding First Central Hospital, Baoding 071000, Hebei Province, China
Author contributions: Zhao X was the pathologist involved in the patient’s diagnosis and follow-up, reviewed the literature and contributed to drafting the manuscript; Zhang G was the surgeon involved in the patient’s management and therapy, and performed the tumor consultation; Li CC was responsible for revision of the manuscript for important intellectual content, contributed to manuscript drafting and revision. All authors approved the final version of the paper prior to submission.
Informed consent statement: Informed written consent was obtained from the patient for publication of this report and any accompanying images.
Conflict-of-interest statement: The authors declare that they have no conflict of interest.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
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: Chun-Hui Li, MD, Chief Doctor, Department of Pathology, The Affiliated Hospital of Chengde Medical University, No. 36 Nanyingzi Street, Chengde 067000, Hebei Province, China. 23131675@qq.com
Received: January 10, 2021
Peer-review started: January 12, 2021
First decision: March 14, 2021
Revised: March 28, 2021
Accepted: April 13, 2021
Article in press: April 13, 2021
Published online: June 26, 2021
Processing time: 152 Days and 8.6 Hours
Abstract
BACKGROUND

Collision carcinoma is a rare histological pattern, and includes two or more different types of tumors coexisting in the same organ as one neoplasm. Different to the combined type, the two adjacent tumors of collision carcinoma are histologically distinct. Collision carcinoma may occur from any origin or organ, including the cecum, liver, cervix, thyroid, stomach, kidney, and esophagus. In the rectum, adenocarcinoma is the most common pathological type, the combined type is rare, and collision tumors are even rarer. To date, only a limited number of collision carcinoma cases originating from the rectum have been reported. Due to the scarcity of rectal collision carcinoma, more cases need to be reported to fully understand the clinico-pathological features and biological behavior of the tumor.

CASE SUMMARY

Here we report a 40-year-old female who presented with the chief complaints of persistent changes in bowel habits and hematochezia for 10 d. She underwent Miles' operation which revealed a collision carcinoma of the rectum, showing a “side by side” pattern, composed of a high grade neuroendocrine carcinoma, (small cell carcinoma) and moderately differentiated adenocarcinoma, based on its clinico-pathological features and biological behavior. The patient remained disease-free at 12 mo follow-up. We also focused on the related literature and expert opinion.

CONCLUSION

Collision carcinoma is a rare tumor with ambiguous biological behavior. Greater attention should be paid to its clinico-pathologic diagnosis. Regular and adequate follow-up is essential to help rule out metastasis and assess the prognosis.

Keywords: Collision carcinoma; Rectum; Neuroendocrine carcinoma; Adenocarcinoma; Case report

Core Tip: Combined small cell carcinoma is a rare type of tumor, which has an additional component that consists of any histological type of non-small cell carcinoma, usually adenocarcinoma, squamous cell carcinoma, or large cell carcinoma. Collision carcinoma is even rarer because of the strict diagnostic criteria. To the best of our knowledge, the present case represents the tenth case of primary collision carcinoma of the rectum, consisting of neuroendocrine carcinoma and adenocarcinoma. Moreover, more cases are necessary to understand the prognosis and treatment of collision carcinoma.