Gastric adenocarcinoma is the most common malignancy of the stomach, arising from the glandular epithelium of the gastric mucosa. It accounts for approximately 90-95% of all gastric cancers. According to the Lauren classification, it is divided into two main histological subtypes: intestinal and diffuse. The intestinal type typically presents as a well-defined, polypoid or ulcerative mass, while the diffuse type (including signet ring cell carcinoma) can lead to linitis plastica through submucosal infiltration. On imaging, focal or diffuse wall thickening, irregular enhancement, and obliteration of perigastric fat planes are characteristic findings.
Age Range
40-85
Peak Age
65
Gender
Male predominant
Prevalence
Common
Gastric adenocarcinoma develops through the Correa cascade of chronic gastritis, intestinal metaplasia, and dysplasia, or in the diffuse type through CDH1 gene mutation leading to E-cadherin loss. Helicobacter pylori infection is the most significant risk factor, with chronic inflammation causing mucosal damage and carcinogenesis. The tumor progresses transmurally from the mucosa through the submucosa, muscularis propria, and serosa; the imaging correlation of this layered invasion manifests as loss of wall stratification and irregular enhancement on contrast-enhanced CT. Infiltration of perigastric fat planes indicates T3 stage, while adjacent organ invasion indicates T4 stage, both detected by fat plane obliteration on CT. Lymphatic spread is common, with perigastric and celiac lymph node involvement being critical for N staging; FDG uptake on PET-CT is used for evaluating both the primary tumor and metastatic lymph nodes.
In gastric adenocarcinoma, focal or segmental irregular wall thickening with obliteration of perigastric fat planes is the most important CT finding indicating transmural invasion and locally advanced disease. This finding is critical for differentiation from benign pathologies.
Report Sentence
In the arterial phase, focal/segmental thickening measuring [X] mm with heterogeneous enhancement is noted in the [location] gastric wall.
Report Sentence
In the portal venous phase, [X] mm wall thickening in the [location] gastric wall with loss of wall stratification and obliteration of perigastric fat planes is noted, consistent with T[X] stage.
Report Sentence
Progressive enhancement is noted in the tumoral area in the delayed phase, consistent with desmoplastic stroma.
Report Sentence
On MRI, [X] mm thickening in the [location] gastric wall is noted, hyperintense on T2W, showing diffusion restriction on DWI, with heterogeneous enhancement on post-contrast sequences.
Report Sentence
On EUS, a [X] mm hypoechoic mass in the [location] gastric wall is noted, suggesting T[X] stage consistent with [layer] invasion.
Report Sentence
On PET-CT, increased FDG uptake with SUVmax: [X] is noted in the thickened [location] gastric wall, consistent with metabolically active malignancy.
Report Sentence
On barium study, mucosal irregularity/filling defect/lumen narrowing in the [location] region of the stomach is noted, suspicious for malignant lesion.
Criteria
Intestinal type in the Lauren classification typically presents as a well-defined polypoid or ulcerative mass. On CT, it shows focal eccentric wall thickening with heterogeneous enhancement. It has a strong association with H. pylori and chronic gastritis. It is generally more common in older patients (>60) and males. PET-CT shows higher FDG uptake compared to diffuse type.
Distinct Features
Criteria
Diffuse type adenocarcinoma spreads through submucosal infiltration and typically does not form a distinct mass. It is characterized by diffuse thickening and rigidity of the gastric wall (linitis plastica). On CT, diffuse concentric thickening of the gastric wall and decreased distensibility are observed. It is more common at younger ages and in females. CDH1 gene mutation causes hereditary diffuse gastric cancer syndrome.
Distinct Features
Criteria
Early gastric cancer refers to a stage where the tumor is confined to the mucosa or submucosa, regardless of lymph node status. According to the Japanese classification, there are Type I (protruded), Type II (superficial), and Type III (ulcerative) subtypes. CT sensitivity is limited; EUS and double contrast barium study are more sensitive. Early detection is critical as it is curable with endoscopic submucosal dissection (ESD). 5-year survival is >90%.
Distinct Features
Distinguishing Feature
Distinguishing Feature
Distinguishing Feature
Distinguishing Feature
Distinguishing Feature
Urgency
Management
Biopsy
Not NeededFollow-up
Gastric adenocarcinoma is one of the most common cancers worldwide. Early-stage disease is curable with surgery; advanced disease requires chemotherapy and palliative approaches. Early detection significantly improves survival.