A 41-year-old woman has had diarrhea with weight loss for th…

A 41-year-old woman has had diarrhea with weight loss for the past 6 months.  A biopsy specimen is taken from small intestine.  The patient begins a restricted diet with no wheat or rye grain products and has dramatic improvement.  Which of the following microscopic features is most likely to be seen in the biopsy specimen?