An entity similar in nature, but inherently different from pizza. A pizza sandwich is a sandwich that contains tomato sauce, cheese, and whatever other toppings that are desired. What makes a pizza sandwich different from pizza is the placement of the ingredients between two pieces of bread, in accordance with the definition of a sandwich. This allows for easier consumption and transport of the said food.
Damn Lowry, I'm starving, I could really go for a pizza sandwich.