Understanding Small Bowel Lymphoma: Clinical, Radiological, and Therapeutic Insights

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Understanding Small Bowel Lymphoma: Clinical, Radiological, and Therapeutic Insights

소장 림프종 이해: 임상적, 방사선적, 치료적 통찰력

Introduction

Small bowel lymphoma, although a rare entity, represents a critical diagnostic and therapeutic challenge in gastrointestinal oncology. Accounting for 15–20% of primary gastrointestinal lymphomas, this malignancy may present with vague and non-specific symptoms, delaying diagnosis and treatment. Early recognition using modern imaging modalities and a multidisciplinary treatment approach is essential for improving patient outcomes.

Primary Keywords: Small bowel lymphoma, GI lymphoma diagnosis, CT imaging, intestinal lymphoma, B-cell lymphoma, non-Hodgkin lymphoma

Epidemiology

Primary gastrointestinal lymphomas account for only 1% to 4% of all gastrointestinal malignancies and roughly 10% to 15% of all non-Hodgkin lymphomas (NHLs) [1]. The small intestine is the second most common site after the stomach, with the ileum being the most frequently involved segment due to its abundance of lymphoid tissue (Peyer's patches).

  • Most common age group: 50–70 years

  • Gender: Male predominance (M:F = 2:1)

  • Histological subtypes:

    • Diffuse large B-cell lymphoma (DLBCL) – Most common

    • MALT lymphoma, Burkitt lymphoma, Enteropathy-associated T-cell lymphoma (EATL)

Etiology and Risk Factors

The development of small bowel lymphoma is influenced by genetic, immunologic, and environmental factors. Key risk factors include:

  • Chronic inflammatory diseases:

    • Celiac disease – associated with EATL

    • Crohn’s disease

  • Immunodeficiency (congenital or acquired, e.g., HIV/AIDS)

  • Helicobacter pylori infection (gastric MALT can occasionally extend)

  • Immunosuppressive therapy post-transplant

  • Autoimmune diseases – e.g., Sjögren's syndrome, rheumatoid arthritis

Pathophysiology

Small bowel lymphoma arises from mucosa-associated lymphoid tissue (MALT) and invades the submucosa, eventually penetrating through all layers of the intestinal wall.

Mechanism:

  • Uncontrolled proliferation of lymphocytes (typically B cells)

  • Destruction of normal bowel architecture

  • Formation of tumor masses, ulcers, strictures, or fistulae

  • Lymphatic spread to mesenteric nodes

  • Hematogenous spread in aggressive forms

Clinical Presentation

Symptoms are typically nonspecific and may mimic Crohn’s disease or tuberculosis.

Common symptoms:

  • Abdominal pain

  • Weight loss

  • Bloating

  • GI bleeding (occult or overt)

  • Nausea/vomiting

  • Intermittent bowel obstruction

  • “B symptoms”: Fever, night sweats, weight loss (in systemic involvement)

Red flag: Sudden onset of obstructive symptoms or bleeding in a middle-aged male with chronic inflammatory bowel disease may raise suspicion.

Imaging Features

Radiological imaging plays a pivotal role in both diagnosis and staging.

1. CT Imaging (with contrast)

Figure 1: Segmental circumferential thickening of the ileum with aneurysmal dilation, a classic radiologic hallmark of small bowel lymphoma.

  • Aneurysmal dilatation of the bowel lumen due to destruction of the muscularis propria and autonomic plexus

  • Homogeneous or heterogeneous wall thickening

  • Mesenteric lymphadenopathy (non-necrotic)

  • May lack obstruction despite large size

2. Barium Studies (less common today)

  • “Sandwich sign”: Mesenteric mass encasing vessels and bowel

  • Fold thickening with ulcerations

  • Nodular pattern or polypoid masses

3. PET-CT and MRI

  • PET-CT: Useful for detecting occult disease and staging

  • MRI enterography: Preferred in younger patients; shows mural infiltration and extramural spread

Figure 2: PET-CT image showing metabolically active bowel lymphoma with nodal involvement.

Diagnosis

Diagnosis of small bowel lymphoma requires integration of:

  • Endoscopic biopsy (push enteroscopy, capsule endoscopy, or double-balloon enteroscopy)

  • Histopathology:

    • Large atypical lymphoid cells

    • Positive CD20, Bcl-6 (B-cell markers)

  • Immunohistochemistry and Flow Cytometry

  • Staging using the Ann Arbor or Lugano classification

  • Bone marrow biopsy (for systemic involvement)

Treatment Options

1. Chemotherapy

  • R-CHOP regimen for DLBCL (Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, Prednisolone)

  • Enteropathy-associated T-cell lymphoma (EATL) responds poorly to standard chemo

2. Surgical intervention

  • Reserved for:

    • Complications (perforation, obstruction, hemorrhage)

    • Diagnostic uncertainty

3. Radiation therapy

  • Limited use in the small bowel

  • More useful in localized gastric or nodal disease

4. Stem cell transplant

  • Considered in relapsed or refractory disease

Prognosis

The prognosis depends on:

  • Histologic subtype (B-cell types have a better prognosis than T-cell types)

  • Stage at diagnosis

  • Patient’s immune status

  • Response to chemotherapy

5-year survival:

  • ~80% for localized DLBCL with R-CHOP

  • <30% for EATL or late-stage disease

Quiz

1. Which of the following is the most characteristic imaging finding of small bowel lymphoma?

A. Apple core lesion
B. Target sign
C. Aneurysmal dilation with wall thickening
D. Pneumatosis intestinalis

2. Which histologic subtype of small bowel lymphoma is most common?

A. MALT lymphoma
B. Enteropathy-associated T-cell lymphoma
C. Burkitt lymphoma
D. Diffuse large B-cell lymphoma

3. What is the most appropriate next step for a patient with suspected small bowel lymphoma and CT findings of segmental thickening with mesenteric nodes?

A. Start empirical antibiotics
B. Schedule colonoscopy
C. Perform an enteroscopic biopsy
D. Refer for surgery immediately

Answer & Explanation

1. Answer: C. Aneurysmal dilation with wall thickening
Explanation: Lymphoma destroys the muscularis layer, leading to dilation rather than obstruction—a hallmark imaging feature.

2.  Answer: D. Diffuse large B-cell lymphoma
Explanation: DLBCL accounts for the majority of small bowel lymphomas and shows good response to R-CHOP.

3. Answer: C. Perform enteroscopic biopsy
Explanation: Definitive diagnosis requires histological confirmation via enteroscopy and biopsy.

Conclusion

Small bowel lymphoma is an elusive but clinically significant malignancy of the gastrointestinal tract. Awareness of its subtle imaging signs—particularly aneurysmal dilation, wall thickening, and lack of obstruction—is crucial for early diagnosis. Integration of cross-sectional imaging with endoscopic biopsy, followed by tailored chemotherapy regimens, can drastically improve outcomes. A multidisciplinary approach remains the cornerstone of care in managing this challenging malignancy.

References

[1] A. G. Ng, T. P. Lee, “Gastrointestinal lymphoma: An overview,” Clin Radiol, vol. 67, no. 10, pp. 909–917, 2012.
[2] K. S. Zahir, M. G. Strickland, “Primary Small Bowel Lymphoma: Imaging Diagnosis,” Radiographics, vol. 35, no. 1, pp. 103–115, 2015.
[3] R. Dawson et al., “Primary malignant lymphomas of the intestinal tract,” Br J Surg, vol. 36, no. 144, pp. 55–66, 1948.
[4] M. H. Kim et al., “PET-CT in gastrointestinal lymphoma,” Korean J Radiol, vol. 12, pp. 229–239, 2011.
[5] A. A. Shiraishi, “CT findings in patients with GI lymphoma,” Abdom Imaging, vol. 29, pp. 82–87, 2004.
[6] B. R. Smith et al., “Management of GI lymphomas: Surgery vs. medical therapy,” Am J Surg, vol. 198, pp. 722–727, 2009.
[7] J. I. Lee, C. H. Kim, “Enteropathy-associated T-cell lymphoma: Features and therapy,” Hematol Oncol Clin North Am, vol. 23, no. 4, pp. 789–807, 2009.

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