Objective: Differentiated gastric cancer generally develops in the atrophic gastric mucosa, although undifferentiated cancer is sometimes encountered in patients with severe atrophic gastritis. We characterized the endoscopic features of undifferentiated gastric cancer in patients with severe atrophic gastritis.
Methods: Stage IA early gastric cancer was diagnosed in 501 patients who were admitted to our hospital between April 2003 and March 2012. The endoscopic and pathological findings were compared among 29 patients with undifferentiated cancer and severe atrophic gastritis, 104 patients with undifferentiated cancer and mild/moderate atrophic gastritis and 223 patients with well-differentiated cancer and severe atrophic gastritis. Endoscopic atrophic gastritis was classified according to the Kimura-Takemoto classification as no gastritis, C-1 and C-2 (mild), C-3 and O-1 (moderate) or O-2 and O-3 (severe).
Results: The tumors were larger and showed deeper mural invasion in the patients with undifferentiated cancer and severe atrophic gastritis than in those with well-differentiated cancer and severe gastritis or undifferentiated cancer and mild/moderate gastritis. On endoscopy, undifferentiated cancer associated with severe gastritis was often red in color.
Conclusion: It is often difficult to diagnose early undifferentiated gastric cancer, especially in patients with severe atrophic gastritis. The present study characterized the important endoscopic features of such tumors.