Duodenal Lymphoma

Duodenal lymphoma is a primary or secondary lymphoma of the duodenum. Gastrointestinal lymphoma is the commonest extranodal site, and the small bowel makes up under 5% of gastrointestinal lymphoma, with the duodenum less affected than the jejunum and ileum.

Types are duodenal type follicular lymphoma (the commonest in the second part of the duodenum, indolent, stage I in most), diffuse large B-cell lymphoma (aggressive), extranodal marginal zone (MALT) lymphoma, mantle cell lymphoma (multiple lymphomatous polyposis), Burkitt lymphoma and, less often, enteropathy associated T-cell lymphoma.

Risk factors are coeliac disease, immunosuppression, HIV, Helicobacter pylori (MALT lymphoma), inflammatory bowel disease and previous transplant.

Pathophysiology.

Duodenal type follicular lymphoma carries t(14;18) with BCL2 overexpression. Large B-cell lymphoma arises de novo or from transformation of indolent disease.

Often incidental in follicular lymphoma. Others present with abdominal pain, nausea, bleeding, anaemia, obstruction, perforation, weight loss and fever.

Red flags.

• Obstruction or perforation.
• Gastrointestinal bleeding.
• B symptoms.
• Raised lactate dehydrogenase.

Endoscopy shows multiple small white granular polyps (follicular), bulky ulcerated masses or thickened folds. Biopsy with immunohistochemistry (CD20, CD10, BCL2, BCL6, Ki-67, cyclin D1, CD3, CD5) and fluorescence in situ hybridisation for t(14;18). Stage with positron emission tomography-CT and capsule or double balloon endoscopy for the small bowel, and bone marrow examination when indicated. Test for Helicobacter pylori, HIV and hepatitis B and C. Lactate dehydrogenase and urate are measured.

Differential diagnosis.

• Lymphoid hyperplasia.
• Coeliac disease and refractory sprue.
• Adenocarcinoma.
• Neuroendocrine tumour.
• Crohn disease.
• Infection.

• Duodenal type follicular lymphoma, localised and low burden: observation (watch and wait) with endoscopy every 6 to 12 months. Treat when symptoms or progression develop.
• Rituximab: 375 mg/m2 IV once weekly for 4 doses; single course, may repeat on relapse; maximum 375 mg/m2 for each dose and 4 doses in a course; monitor infusion reactions, hepatitis B reactivation, blood counts; screen for hepatitis B first; no renal dose change.
• Localised disease: involved site radiotherapy 24 Gy in 12 fractions is an alternative.
• Large B-cell lymphoma: R-CHOP every 21 days for 6 cycles: rituximab 375 mg/m2 IV on day 1, cyclophosphamide 750 mg/m2 IV on day 1, doxorubicin 50 mg/m2 IV on day 1, vincristine 1.4 mg/m2 IV on day 1 (capped at 2 mg) and prednisolone 100 mg orally on days 1 to 5; maximum lifetime doxorubicin 450 to 550 mg/m2; monitor blood counts before each cycle, echocardiography at baseline and by cumulative dose, liver function, tumour lysis and neuropathy; reduce doxorubicin and vincristine in hepatic impairment (raised bilirubin) and delay for neutrophils under 1.0 x 10^9/L; reduce cyclophosphamide in severe renal impairment.
• Hepatitis B prophylaxis for core antibody positive patients: entecavir 0.5 mg orally once daily, from before therapy until 12 months after; maximum 0.5 mg daily; monitor liver function and viral load; give 0.5 mg every 48 hours when creatinine clearance is 30 to 49 mL/min.
• MALT lymphoma: eradicate Helicobacter pylori if present, then observe or give rituximab based treatment for persistent disease.

Surgery is reserved for perforation, obstruction or bleeding.

Monitoring. Positron emission tomography-CT after treatment, endoscopy at 3 to 6 months, and relapse surveillance for 5 years.

Referral and escalation. Haematology oncology urgently for aggressive lymphoma; surgical review for complications.