Metastatic Sarcoidosis of Terminal Ileum and Colon: Very Rare, but Important to Differentiate From Crohn’s Disease

Abstract

Introduction: Sarcoidosis prevalence is reported to be 1-40 per 100,000 in the United States, but intestinal tract involvement is only 3.4% of that, with small bowel involvement considered to be the rarest. For Crohn’s disease, terminal ileum is the most common site, whereas for sarcoidosis, it is the least likely site in intestinal tract. A 66-year-old white male with history of hypertension, remote pulmonary sarcoidosis for 8 years came with complaint of increasing frequency of bowel movements for the past 2 months. Patient denied any other complaints. He was on amlodipine and tamsulosin. He had a 10-pack-year smoking history. Chest x-ray showed resolution of lymphadenopathy seen 8 years ago. CT scan of the abdomen showed small pulmonary nodules and mild splenomegaly. WBC count was 3900/uL, absolute neutrophil count was 3100/uL, with hemoglobin 13 g/dL, MCV 87.4 fL, calcium 8.7 mg/dL with normal chemistry and liver function tests. Outpatient colonoscopy showed 2 mm yellowish plaque-like lesions in colon and thickened folds in terminal ileum. Biopsy report showed multiple non-caseating granulomas involving the lamina propria and the submucosal tissue in both the colon and terminal ileum. Special stains for fungi and acid fast bacilli were negative. A diagnosis was made of small and large bowel sarcoidosis. Usually, treatment is indicated when organ function is impaired. It is not clear whether to treat asymptomatic gastrointestinal sarcoidosis or not. We decided not to treat the patient and follow up very closely. Sarcoidosis can mimic Crohn’s disease because of its non-caseating granulomatous pattern, but diagnosis is made based upon compatible history, demonstration of granulomas in at least 2 different organs, negative staining and culture for acid fast bacilli and fungi, absence of occupational or domestic exposure to toxins, and lack of drug induced disease. On biopsy, it can be differentiated by presence of Schaumann bodies, prominent intramucosal rather than sparse submucosal granumolas, lack of mucosal architectural distortion, acute inflammation, and lack of fistulas. In a very difficult case, ACE level can be really helpful too.Figure 1: Transverse colon sarcoidosis.