Small Bowel Aneurysmal Dilatation Differential Diagnosis

Small bowel aneurysmal dilatation is a common pattern of disease in the small bowel. It consists of a focal segment of dilated small bowel associated with a mass. The mass is typically circumferential. The mnemonic MALL can be used to recall the common diagnoses.

	Disease	Notes
M	Malignant GIST	Lymphadenopathy absent; obstruction common
A	Adenocarcinoma of small bowel
L	Lymphoma	Lymphadenopathy present; obstruction uncommon
L	Leiomyosarcoma

Left Upper Quadrant Small Jejunal Aneurysmal Dilatation
Source: Radiology Assistant

Metastatic disease can also present with small bowel aneurysmal dilatation. The most common primary is melanoma, followed by lung, breast, and colon cancer. Metastases tend to be multifocal and necrotic.

References:

• Fundamentals of Diagnostic Radiology
• Fundamentals of Body CT
• Thai Journal of Gastroenterology
• Lymphoma Involving Distal Ileum | AJR