Ulcerative Colitis with Subsequent Development of Collagenous Colitis: Evolution or Incident

Abstract

Purpose: Collagenous colitis (CC) is a subclass of microscopic colitis. It has a peak incidence of approximately 25-30 cases per 100,000 in women over the age fifty. Medications, luminal toxins, infections, bile acids, nitric oxide and genetics are etiological contribution. Moreover, autoimmune conditions are reported associations with CC. Most common presentation is watery, non-bloody, chronic diarrhea with normal endoscopic findings. Only one case has been reported of ulcerative colitis (UC) with subsequent development of CC. We describe a case of quiescent UC with symptoms of watery, non-bloody diarrhea; ensuing endoscopic and histologic examinations were consistent with CC. Case Description: The patient is a 72 year old woman with long standing history of UC, which had been in remission over the past few years. Most recently, she developed non-bloody, watery diarrhea without additional symptoms. Her medical history is significant for Graves disease, treatment-induced hypothyroidism, and UC. Medications include Levothyroxine and daily multi-vitamin supplement. No significant findings were observed on the physical exam. Subsequent endoscopic mucosal evaluation was unremarkable. Histological evaluation revealed quiescent colitis, and a subepithelial collagen band with surface epithelial cell damage. Discussion: Evolution of ulcerative colitis to CC seems unlikely given the fibrotic tissue only deposits under the surface epithelium. This pattern of peculiar deposition is seen elsewhere in the autoimmune conditions of the kidney. Similar to pattern of collagen deposition in CC, early periglomerular deposits end up with scarring. Perhaps an autoimmune process is paramount in the development of CC.Figure. 10: x Trichrome Stain. Quiescent ulcerative colitis with marked thickened subepithelial collagen layer (collagenous colitis).