Differential Diagnosis for Right Lower Quadrant Distal Small Bowel Narrowing and Narrowing of the Cecum/Ileocolic Junction

• Single Most Likely Diagnosis
  • Crohn's disease: This is a common cause of narrowing in the distal small bowel and the cecum/ileocolic junction due to its tendency to affect the terminal ileum and cause strictures.
• Other Likely Diagnoses
  • Tuberculosis: Intestinal tuberculosis can cause narrowing and strictures, particularly in the ileocecal region, due to its predilection for affecting the cecum and terminal ileum.
  • Carcinoid tumor: These tumors can cause fibrosis and narrowing, especially in the small intestine, and are known to occur in the distal small bowel.
  • Lymphoma: Intestinal lymphoma can cause narrowing and obstruction, particularly if it involves the distal small bowel or the cecum/ileocolic junction.
• Do Not Miss Diagnoses
  • Intussusception: Although less common in adults, intussusception can cause bowel obstruction and must be considered, especially if there's a lead point like a tumor.
  • Volvulus: A twisting of the bowel can cause obstruction and ischemia, making it a critical diagnosis not to miss.
  • Ischemic bowel disease: Ischemia can cause narrowing and strictures, particularly if there's chronic or recurrent ischemia affecting the bowel.
• Rare Diagnoses
  • Eosinophilic gastroenteritis: This condition can cause bowel wall thickening and narrowing, although it's less common and typically presents with eosinophilia.
  • Scleroderma: This autoimmune disease can cause fibrosis and narrowing of the bowel, particularly in the small intestine, but it's relatively rare.
  • Amyloidosis: Systemic amyloidosis can deposit amyloid proteins in the bowel wall, leading to thickening and narrowing, but this is a rare condition.