Histological transformation to signet-ring cell carcinoma in a patient with clinically aggressive poorly differentiated adenocarcinoma of the ascending colon after response to chemotherapy plus cetuximab: a case report

Sep 24, 2026

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Chemotherapy response in colorectal cancer can alter chemosensitivity or tumor aggressiveness, while liquid biopsy studies suggest evolving oncogene mutations. Histological transformation to signet-ring cell carcinoma is reported as exceptionally rare in colorectal cancer. This case report describes transformation of clinically aggressive scirrhous-type poorly differentiated adenocarcinoma of the ascending colon into signet-ring cell carcinoma across almost all recurrent tumors confirmed at autopsy following chemotherapy plus cetuximab.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages11

Reading Time28 min

AccessFree to download

Abstract

Background

Case presentation

Patient presentation and initial treatment response

Recurrence, autopsy findings, and outcome

Conclusion

Keywords

Nagano et al. World Journal of Surgical Oncology (2023) 21:172 [https://doi.org/10.1186/s12957-023-03053-2](https://doi.org/10.1186/s12957-023-03053-2) World Journal of Surgical Oncology CASE REPORT Open Access Histological transformation to signet-ring cell carcinoma in a patient with clinically aggressive poorly differentiatedadenocarcinoma of the ascending colon after response to chemotherapy plus cetuximab: a case report Hideki Nagano 1*, Shigekazu Ohyama1, Atsushi Sato1, Jun Igarashi 1, Tomoko Yamamoto1, Masumi Kadoya2 and Mikiko Kobayashi3 Abstract Background Alteration of chemosensitivity or tumor aggressiveness in response to chemotherapy has been reported, and liquid biopsy assessment during chemotherapy for colorectal cancers has confirmed the acquisition of mutations in various oncogenes. However, the occurrence of histological transformation seems to be extremely rare in colorectal cancers, and the few existing case reports of this transformation are from lung cancer and breast cancer. In this report, we describe the histological transformation of clinically aggressive scirrhous-type poorly differentiatedadenocarcinoma of the ascending colon to signet-ring cell carcinoma in almost all recurrent tumors that were confirmed by autopsy after response to chemotherapy plus cetuximab. Case presentation A 59-year-old woman visited our hospital with whole abdominal pain and body weight loss and was diagnosed with scirrhous-type poorly differentiated adenocarcinoma of the ascending colon with aggressive lymph node metastases. The intrinsic chemosensitivity of the tumors was evident upon initiation of mFOLFOX6 plus cetuximab therapy, and right hemicolectomy was performed, and the tumor obviously remained in the peripancreatic area, paraaortic region, or other retroperitoneal areas. The ascending colon tumors mainly consisted of poorly differentiated adenocarcinoma and were not associated with signet-ring cell components except for minute clusters in a few lymphatic emboli in the main tumor. Chemotherapy was continued, and metastases were eliminated at 8 months after the operation; this response was maintained for an additional 4 months. Discontinuation of chemotherapy plus cetuximab resulted in immediate tumor recurrence and rapid expansion, and the patient died of the recurrent tumor 1 year and 2 months after the operation. Autopsy specimens revealed that almost all of the recurrent tumors exhibited transformation and consisted of signet-ring cell histology. *Correspondence: Hideki Nagano [naganohideki06s@gmail.com](naganohideki06s@gmail.com) Full list of author information is available at the end of the article © The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit [http://creativecommons.org/licenses/by/4.0/](http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver ()[. The Creative Commons Public Domain Dedication waiver (](http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver ()[http://creativeco](http://creativeco)[mmons.org/publicdomain/zero/1.0/](mmons.org/publicdomain/zero/1.0/)) applies to the data made available in this article, unless otherwise

FAQs

What histological change occurred in this patient after chemotherapy plus cetuximab?

The clinically aggressive scirrhous-type poorly differentiated adenocarcinoma of the ascending colon transformed into signet-ring cell carcinoma in almost all recurrent tumors.

What was the patient’s initial clinical course with mFOLFOX6 plus cetuximab?

After starting mFOLFOX6 plus cetuximab, the intrinsic chemosensitivity was evident and metastases were eliminated by 8 months post-operation, with response maintained for an additional 4 months.

How did stopping chemotherapy plus cetuximab affect disease progression and survival?

Discontinuation resulted in immediate tumor recurrence with rapid expansion, and the patient died from recurrent tumor 1 year and 2 months after the operation.

Sep 24, 2026

Uploaded by Ophelia