An Unusual Cause of Severe Wall Thickening and Stenosis of the Sigmoid Colon Accompanied by Polyposis

Question: A 78-year-old woman with a history of hyperlipidemia and hypertension was referred to our department for further examination of frequent mucous and bloody diarrhea (10 times/d) and abdominal pain that had persisted for approximately 6 months. She had chronic constipation and difficulty defecating for more than 20 years. Physical examination revealed bilateral leg edema. Blood examination showed a normal white blood cell count and anemia (red blood cell count, 274 × 104 cells/μL, normal range [NR], 386–492 × 104 cells/μL; hemoglobin, 7.7 g/dL, NR, 11.6–14.8 g/dL; hematocrit, 24.8%, NR, 35.1–44.4%). Liver and kidney function test results were normal. Marked hypoalbuminemia (2.2 g/dL, NR, 4.1–5.1 g/dL) was seen, whereas coagulation and thyroid function test results were normal. She tested negative for antibodies against antinuclear antibodies and antineutrophil cytoplasmic antibodies against proteinase-3 or myeloperoxidase. Levels of serum C-reactive protein (CRP; 4.40 mg/dL, NR, 0–0.14 mg/dL), soluble interleukin-2 receptor (968 U/mL, NR, 121–613 U/mL), and interleukin-6 (29 pg/mL, NR, <7 pg/mL) were elevated. She tested negative for infection with Helicobacter pylori, tuberculosis, and cytomegalovirus since serum antibodies against H pylori, interferon-g release assay against tuberculosis, and cytomegalovirus antigenemia, respectively, were absent. Contrast-enhanced computed tomography (CT) revealed severe wall thickening limited to the sigmoid colon (Figure A). CT also revealed the severe stenosis of the distal and middle portions of the sigmoid colon (Figure A, arrowheads). Total colonoscopy revealed that the distal and middle portions of the sigmoid colon were stenotic because of the presence of numerous colonic polyps, most of which were sessile and covered by mucus exudate (Figure B, left, distal sigmoid colon; right, middle sigmoid colon). Polyposis was distributed throughout the sigmoid colon. Severe stenosis of the distal and middle portions of the sigmoid colon was visualized on gastrografin enema during colonoscopy (Figure C, arrowheads).