Published online Jan 15, 2023. doi: 10.4251/wjgo.v15.i1.186
Peer-review started: October 8, 2022
First decision: October 17, 2022
Revised: October 31, 2022
Accepted: December 6, 2022
Article in press: December 6, 2022
Published online: January 15, 2023
Processing time: 94 Days and 3.2 Hours
Mucinous adenocarcinoma of the colorectum is a rare histological subtype characterized by an abundant mucinous component. Mucinous tumors are frequently diagnosed at an advanced stage, which indicates an aggressive subtype. However, few case reports have been published, and little information is available concerning genetic alterations in mucinous adenocarcinoma.
A 76-year-old man underwent en bloc endoscopic submucosal dissection (ESD) for the management of a type 0-Is+IIa lesion. Histological examination revealed an intramucosal mucinous adenocarcinoma with signet-ring cell carcinoma and well-to-moderately differentiated tubular adenocarcinoma. Three years after the ESD, local recurrence was detected by an endoscopic examination, revealing a new 0-Is+IIa lesion with a phenotype similar to the previously resected lesion. Re-ESD was chosen for the management of the recurrent tumor, and the histological examination showed positive tumor infiltration at the vertical margin. Additional surgical resection was performed for the curative treatment. Genetic analysis showed pathogenic alterations in RNF43 and TP53 in the adenoma and an additional SMAD4 alteration in the carcinoma.
This mucinous mucosal adenocarcinoma case was suggested to have an aggressive phenotype and a careful and close follow-up are required.
Core Tip: Colorectal mucinous adenocarcinoma, as characterized by an abundant mucinous component, is a rare histological subtype frequently diagnosed at an advanced stage. Intramucosal mucinous adenocarcinoma was dissected by endoscopic submucosal dissection and local recurrence was detected three years after the treatment. Genetic analysis showed pathogenic alterations of RNF43, TP53, and SMAD4. This case of mucinous mucosal adenocarcinoma was suggested to have an aggressive phenotype based on the treatment course and advanced genotype identified by target sequencing. Careful and close follow-up should be performed, and additional surgery should be considered when managing patients with mucinous adenocarcinoma.