Case Report
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Dec 6, 2019; 7(23): 4063-4074
Published online Dec 6, 2019. doi: 10.12998/wjcc.v7.i23.4063
Micronodular thymic tumor with lymphoid stroma: A case report and review of the literature
Bei Wang, Kai Li, Qing-Kun Song, Xiu-Hong Wang, Lei Yang, Hong-Lei Zhang, Ding-Rong Zhong
Bei Wang, Xiu-Hong Wang, Lei Yang, Hong-Lei Zhang, Ding-Rong Zhong, Department of Pathology, China-Japan Friendship Hospital, Beijing 100029, China
Kai Li, Department of Surgical Oncology, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China
Qing-Kun Song, Department of Science and Technology, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China
Author contributions: Zhong DR was responsible for the overall design of the paper and reviewed the contents of the paper; Wang B performed the histological examination of the case, was responsible for retrieving, reading, and collating the references, and was also a major contributor in writing the manuscript; Li K was responsible for retrieving, reading, and screening of the literature; Song QK was responsible for all statistical work; Wang XH performed the histological examination of the case and took all the pictures; Yang L and Zhang HL were responsible for all histological staining, immunohistochemical staining, and molecular detection. All authors read and approved the final manuscript.
Informed consent statement: The patient was asked to sign an informed consent statement for the publication. This work was approved by the ethics committee of China-Japan Friendship Hospital.
Conflict-of-interest statement: No conflict of interest exists in the submission of this manuscript. The authors declare that they have no competing interests.
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 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: Ding-Rong Zhong, MD, Director, Professor, Department of Pathology, China-Japan Friendship Hospital, 2 Yinghuayuan Dongjie, Beijing 100029, China. txzzzryy@163.com
Telephone: +86-10-69159370
Received: March 6, 2019
Peer-review started: March 8, 2019
First decision: September 9, 2019
Revised: October 16, 2019
Accepted: November 14, 2019
Article in press: November 14, 2019
Published online: December 6, 2019
Processing time: 276 Days and 8 Hours
Abstract
BACKGROUND

Micronodular thymic tumors with lymphoid stroma include micronodular thymoma with lymphoid stroma (MNT) and micronodular thymic carcinoma with lymphoid hyperplasia (MNC), whose micromorphological features are lymphoid stromal hyperplasia and nodular arrangement of tumor epithelial cells. This type of tumor is rare; therefore, the corresponding clinical guidelines, histopathological diagnostic criteria, prognostic factors, and therapeutic regimens have not been established.

CASE SUMMARY

This study covers a novel presentation of MNC in a patient and summarizes the clinicopathological characteristics of this type of tumor by using pooled-analysis methods. Morphologically, this tumor type is a series of benign to malignant pedigrees. We establish the following criteria for the classification of micronodular thymic tumors with lymphoid stroma: (1) Tumor cells with moderate-to-severe dysplasia; (2) Tumor cell mitotic figures > 2/10 high-power fields; (3) Appearance of neoplastic necrosis; (4) No terminal deoxynucleotidyl transferase-positive immature T lymphocytes within the tumor; (5) Tumor cells with a Ki-67 index ≥ 10%; and (6) Tumor cells express CD5. Cases that fall into the borders of two categories in terms of morphology are attributed to atypical MNT. It is proposed that the diagnosis of MNT should be established on the diagnostic criteria mentioned above.

CONCLUSION

Our diagnostic algorithm can effectively distinguish malignant tumors from benign tumors and provides a potent basis for predicting a prognosis, which offers a practical reference for oncologists and pathologists.

Keywords: Micronodular thymic tumors with lymphoid stroma; Micronodular thymoma with lymphoid stroma; Micronodular thymic carcinoma with lymphoid hyperplasia; Thymus; Case report

Core tip: This study covers a novel presentation of micronodular thymoma with lymphoid stroma in a patient and summarizes the clinicopathological characteristics of this type of tumor by using pooled-analysis methods. Morphologically, this tumor type contains a series of benign to malignant pedigrees. We established criteria for the classification of micronodular thymic tumors with lymphoid stroma. Our diagnostic algorithm can effectively distinguish malignant tumors from benign tumors and provides a potent basis for predicting patient prognosis.