Figure 5

Duplicated muscularis mucosa. Both images show this (H&E, left, and cocktail CD31/SMA immunohistochemistry, right). This architectural anomaly has been implicated in the inadequate staging of endoscopic ultrasound. The differential risk of metastasis between deep and superficial submucosal layers is yet to be determined. m.m., muscularis mucosa; m.p., muscularis propria.