"Crawling-type" early gastric carcinoma (EGC) is a rare subtype of gastric cancer (GC) that is challenging to diagnose at an early stage due to its low-grade nuclear heterogeneity and morphology that mimics intestinal metaplasia. This study aimed to explore the clinical characteristics and pathological features of patients with crawling-type EGC.

This case series study retrospectively included patients with crawling-type EGC who underwent endoscopic submucosal dissection (ESD) or gastrectomy at the East Hospital Affiliated to Tongji University between January 2019 and March 2022.

8 patients (mean age 63.5 ± 7.8 years) were included: 4 underwent ESD, and 4 underwent partial gastrectomy. In 4 patients, the tumors were primarily located in the gastric cardia and the basal gland area of the upper stomach, while the other 4 patients had tumors in the antral region. Preoperative gastroscopy revealed atrophic gastritis and intestinal metaplasia in all patients. The lesions were generally flat in morphology. Submucosal infiltration was found in only one case. Signet ring cells were present in the tumors of 5 patients. The mucinous type was observed in 7 patients. Seven tumors were of the gastrointestinal mixed type. Curative resection was achieved in all patients. No recurrence events were observed in any patient at 1 year after surgery.

The crawling-type EGC may exhibit distinct clinical characteristics and pathological features compared with classical GC. Curative resection was achieved in all patients. The short-term prognosis of surgical treatment may be favorable.

Crawling-type gastric adenocarcinoma is a rare subtype of gastric cancer with diagnostic and therapeutic challenges due to its flat, ill-defined lesions. Advanced diagnostic techniques, such as narrow-band imaging and linear endoscopic ultrasonography, improve detection, but endoscopic submucosal dissection poses a risk of incomplete resection. Despite negative resection margins, vigilant postoperative monitoring is crucial due to the potential for recurrence. This letter highlights the importance of refined diagnostic criteria, individualized treatment approaches, and continuous follow-up to optimize management of this unique gastric cancer subtype.

In this editorial we comment on the article by Xu et al. Gastric adenocarcinoma (GA) is a malignancy which arises from the gastric mucosa and encompasses heterogenous tumors with varying characteristics. There are two main classifications: Lauren's and the World Health Organization distinguishing the diverse types of GA depending on clinical, genetic, morphological and epidemiological features. "Crawling-type" adenocarcinoma (CRA) is a subtype characterized by irregularly fused glands with low-grade cellular atypia. Moreover, CRA represents differentiated tumor cells resembling intestinal metaplasia which results in misdiagnosis. The diagnosis is of utmost importance, as well as the subclassification and thorough pathological assessment. With regard to the symptoms of GA, these depend on the stage of the disease. Diagnostic methods play a crucial role in assessing the extent of the tumor and the stage of the disease. Nevertheless, early detection of CRA remains challenging due to its histological features. In summary, CRA is a distinct type of GA with particular clinicopathological and histological characteristics. Despite its significance, it not distinguished as a subtype, resulting in diagnostic challenges. Diagnosis is based on careful observation and thorough biopsy analysis, indicating the importance of comprehensive pathological assessment.

In this editorial, we comment on an article by Xu et al. This article describes a case of crawling-type gastric adenocarcinoma (CRA) distinguished by its rare occurrence and diagnostic complexity. We reviewed the detailed case-report findings showcasing clinical, pathological, and molecular characteristics of CRA that shed light on its elusive nature and challenges for early detection and treatment. This case underscored the significance of advanced diagnostic tools such as endoscopic submucosal dissection. Emphasis was placed on the molecular peculiarities of CRA, including the higher mutation rates of genes such as TP53 and RHOA and the notable absence of HER2 amplification, differentiating it from more conventional forms of gastric adenocarcinoma. In this editorial, we advocate for a multidisciplinary approach to effectively manage this rare subtype and highlight the necessity for precision in both diagnostic and therapeutic strategies. Moreover, a heightened awareness urging the adoption of advanced diagnostic techniques and collaborative approaches is necessary among clinicians and researchers. We aim to contribute to the ongoing discourse in gastrointestinal oncology, emphasizing the importance of recognizing and addressing the complexities associated with rare cancer subtypes such as CRA.

Crawling-type adenocarcinoma (CRA) is an important gastric cancer (GC) subtype that exhibits a specific histological pattern and has characteristic clinicopathological findings. Despite its characteristic histology, little is known about the molecular characteristics of CRA.

We examined 177 GC cases, including 51 cases of CRA and 126 cases having conventional differentiated adenocarcinomas (CDAs). Results for immunohistochemistry (mucin phenotype; Muc5AC, Muc6, Muc2 and CD10, CDX-2, MLH-1, p53 and β-catenin), mutation analysis (TP53, KRAS and BRAF), microsatellite instability (BAT25, BAT26, D2S123, D5S346 and D17S250), DNA methylation status by a two-panel method (RUNX3, MINT31, LOX, NEUROG1, ELMO1 and THBD), MLH-1 promoter methylation, and allelic imbalance (AI; 1p, 3p, 4p, 5q, 8p, 9p, 13q, TP53, 18q and 22q) were examined.

CRAs were more likely to occur in the middle third of the stomach, in younger patients and to be macroscopically depressed. Nuclear accumulation of β-catenin and loss of MLH-1 expression were less frequent among CRA cases compared to CDA cases. At a molecular level, CRA is often characterized by the deletion mutation c.529_546 (18-base pair deletion at codon 177-182 in exon 5) in the TP53 gene (10 cases). Although the low methylation epigenotype was significantly more frequent for CRAs compared to CDAs, multiple AIs were more often seen in CRAs relative to CDAs.

The results demonstrated that TP53 mutations, particularly c.529_546del, and multiple AIs are closely associated with CRA carcinogenesis. Our results suggest that CRA is an independent entity of GC in terms of clinicopathologic and molecular findings.