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Lee and Kang: Differential Diagnosis for Chronic Diarrhea: Are Multiple Random Biopsies with Colonoscopy Mandatory?


A 65-year-old woman visited our hospital complaining of watery diarrhea and intermittent low abdominal pain for the past 6 months. Her stool frequency was generally 5–10 times a day. Her symptoms did not include fever, weight loss, rectal bleeding, or bowel movements at night. Colonoscopy 6 months ago were not remarkable. She takes aceclofenac for knee pain as needed.
Her complete blood count, blood chemistry, and thyroid function analysis were normal. Results of stool examination, including toxin for Clostridium difficile, were negative, except for a slightly elevated fecal calprotectin level (110 μg/mg). Colonoscopy was performed to identify the cause of chronic diarrhea. The colonic mucosa was relatively normal, but the vascular pattern sporadically decreased (Fig. 1). Multiple random biopsies were performed in the entire colon (Fig. 2).
What is the most likely diagnosis?


Conflicts of Interest: The authors have no potential conflicts of interest.

Fig. 1.
Colonoscopic findings demonstrating a relatively normal colonic mucosa with some areas of decreased vascular pattern in the cecum (A), transverse colon (B), sigmoid colon (C), and rectum (D).
Fig. 2.
Microscopic findings showing a thickened subepithelial collagen band (12 μm) with (A) hematoxylin and eosin stain, ×50 magnification, and (B) Masson’s Trichrome stain, ×100 magnification.


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