Cook macaroni according to package directions. Drain.
Cook celery in chicken broth (or use a chicken-flavored bouillon cube plus ¾ c. water) for 5 minutes.
Combine cooked macaroni, celery, broth, celery soup, mushrooms, chicken, parsley and Worcestershire sauce. Add salt if needed. Pour into greased 2-qt. casserole. Sprinkle with bread cubes; dot with b