Colitis microscópica atípica: descripción de 2 casos de colitis colágena, uno con células gigantes y otro con seudomembranas

We describe two patients with symptoms of microscopic colitis, which microscopically showed collagenous colitis (CC) with atypical features. A 54-year-old patient complained of watery diarrhea following the administration of acarbose for type-2 diabetes, which disappeared after drug withdrawal on two occasions. The colon biopsies showed collagenous colitis containing multinucleated giant cells. A 60-year-old woman with a 3 year history of watery diarrhea underwent colonic biopsies which showed CC with pseudomembranes. The possible etiology of these two atypical variants of microscopic colitis, one of CC with giant cells induced by acarbose and the other of CC with pseudomembranes, is discussed.