In a saucepan, combine chicken broth and frozen chopped broccoli. Bring to a boil.

Reduce heat to low, cover the saucepan, and simmer for 5 minutes. Set aside.

In a separate pan, cook sliced fresh mushrooms and chopped onion in margarine until softened.

Blend in all-purpose flour, 1/2 teaspoon salt, and 1/8 teaspoon pepper.

Gradually add milk to the mushroom mixture, stirring constantly until thickened.

Continue to cook and stir for two more minutes.

Add the broccoli and broth mixture, drained whole corn, and chopped pimento to the sauce.

Heat through for 3 to 4 minutes, stirring occasionally.