Small bowel lymphoma

Lymphoma of the small bowel accounts for 17 - 30% of all primary small bowel malignancies ¹ and 20 - 54% of all primary gastrointestinal lymphomas ^2-3.

Demographics and clinical presentation

Small bowel lymphoma is most commonly seen as secondary extra nodal involvement in widespread systemic lymphoma. When primary it is seen predominantly in well defined patient groups and the demographics therefore match those of said groups. Predisposing conditions include ¹:

• AIDS
• coeliac disease
• organ transplant (see post transplant lymphoproliferative disorder (PTLD)
• Helicobacter pylori positive patients

Presentation is variable and includes ¹ :

• small bowel obstruction
• gastrointestinal haemorrhage
• perforation

Pathology

The type of lymphoma depends on the underlying predisposing condition.

• H pylori -  mucosa-associated lymphoid tissue lymphoma (MALToma)
• PTLD - polyclonal B-cell non-Hodgkin's lymphoma (EBV associated)
• HIV - B-cell non-Hodgkin's lymphoma ³
• T-cell lymphomas are seen but are uncommon ⁵

Radiographic features

Typically small bowel involves a single loop of bowel with 5-20cm of its length demonstrating ³ :

• bowel wall thickening : 1-7cm
• aneurysmal dilatation : 30%

Less frequently the disease may manifest as a solid mass lesion. Despite the extensive involvement small bowel obstruction is uncommon and perforation rare.

Regional lymph node enlargement is seen in approximately 50% of cases.

Treatment and prognosis

Most frequently the involved segment is resected, with subsequent chemoradiotherapy ².

Differential diagnosis

• inflammatory bowel disease, especially Crohn's disease
• adenocarcinooma
• metastases : melanoma, renal cell carcinoma ³
• infection / enteritis
• leiomyoma / leiomyosarcoma / GIST