What gastrointestinal mucosal changes are seen in sarcoidosis?

Gastrointestinal Mucosal Changes in Sarcoidosis

Gastrointestinal (GI) sarcoidosis is rare, occurring in a distinct oral-anal gradient with 80% of cases affecting the upper GI tract (esophagus, stomach, and duodenum), characterized primarily by noncaseating granulomas that can present as mucosal nodules, ulcerations, or exophytic lesions. 1

Epidemiology and Distribution

• GI tract involvement is uncommon in systemic sarcoidosis
• Clear oral-anal gradient exists, with decreasing frequency from proximal to distal GI tract
• Stomach (particularly the antrum) is the most commonly affected extrahepatic GI organ 2
• Small bowel is the least commonly affected segment 2
• Colon involvement is extremely rare 3

Pathological Findings

The hallmark histopathological finding is noncaseating granulomas in the GI mucosa, which may present as:

Mucosal Changes

• Noncaseating granulomas (diagnostic hallmark) 2, 1
• Diffuse mucosal infiltration 1
• Fine mucosal ulcerations (particularly in areas of obstruction) 3
• Nodular mucosal lesions that may mimic polyps 4
• Exophytic endoluminal lesions 1

Structural Changes

• Involvement of the myenteric plexus causing motility disorders 1
• Extrinsic compression from adjacent lymphadenopathy 2
• Strictures leading to obstruction (rare but reported) 3
• Peritoneal studding with nodules (extremely rare) 2

Clinical Presentation

• 10% of cases are asymptomatic, discovered incidentally during endoscopy 1
• GI sarcoidosis can be the first manifestation of systemic disease in approximately 50% of cases 1
• Symptoms vary based on location and extent of involvement:
  • Upper GI: Dysphagia, epigastric pain, early satiety
  • Lower GI: Abdominal pain, altered bowel habits, constipation
  • Severe cases (22%): Bowel obstruction, perforation, or massive hemorrhage 1

Endoscopic Findings

• Nodular mucosal lesions resembling polyps 4
• Diffuse fine ulcerations 3
• Strictures causing luminal narrowing 3
• Normal-appearing mucosa with granulomas on biopsy (subclinical disease)

Diagnostic Approach

1. Endoscopy with biopsy: Essential for diagnosis, showing noncaseating granulomas
2. Differential diagnosis: Must exclude other granulomatous conditions:
   • Tuberculosis
   • Fungal infections
   • Parasitic diseases
   • Inflammatory bowel disease
   • Whipple's disease 5

Treatment Considerations

• Corticosteroids are the first-line therapy for symptomatic GI sarcoidosis 5, 3
• Dramatic response often seen within days of starting treatment 3
• Immunomodulatory therapy may be needed for resistant cases
• Surgical intervention reserved for complications like obstruction, perforation, or massive hemorrhage 5

Important Clinical Pearls

• GI sarcoidosis can mimic malignancy on initial endoscopic evaluation 1
• Follow-up endoscopy after treatment often shows resolution of mucosal lesions 3
• Liver involvement is much more common than hollow GI organ involvement 2
• Diagnosis requires exclusion of other granulomatous diseases and ideally demonstration of sarcoidosis in at least one other organ system 2

Monitoring and Prognosis

• Follow-up endoscopy recommended after treatment to confirm mucosal healing
• Overall prognosis is generally good with appropriate treatment
• Cardiac and pulmonary complications remain the main causes of death in sarcoidosis patients 2

Remember that GI sarcoidosis can present with diverse and sometimes misleading clinical and endoscopic findings. A high index of suspicion is needed, particularly when encountering unusual mucosal lesions or unexplained granulomas on biopsy in patients with known or suspected systemic sarcoidosis.