GI Lymphoma

DEFINITION
Tumour of the lymph tissues
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EPIDEMIOLOGY

2nd most common primary gastric malignancy.
- however only 2% of gastric primary malignancies, because adenoCa = 95%.

Most common malignancy of the bowel mesentery

Risk Fx
Celiac (esp non-Hodgkin T-cell)
H. pylori (MALT)
HIV (B-cell; poor prognosis)

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AETIOLOGY

Lymphoma
Almost all GI are non-Hodgkin lymphomas.
- (difference is lack of Reed-Sternberg cells in non-Hodgkin's; treatments and outcomes very different)
GI = most common site of extranodal lymphoma.

cf 'Psuedo-lymphoma'
Mass of lymphoid tissue in the GI wall; often an overlying ulcer.
- may be a chronic inflammatory reaction.

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BIOLOGICAL BEHAVIOUR

Pathology
Variety of non-Hodgkin subtypes
- vary in behavior, response to chemotherapy & prognosis
Include
- diffuse, B-cell lymphoma (most common)
- MALT (mucosa-associated lymphoid tissue) tumours associated with chronic antigenic stimulation (e.g. H. pylori and automimmune diseases)

Site
Stomach > Small bowel
Most common SB site = ileum.

Primary = usually involve just 1 site
Secondary = multiple sites

Natural history
20% present with a second primary in another organ.
Characteristically bulky at presentation.
5-yr survival is ~50%
- depends on stage, penetration of gastric wall, tumor grade.

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MANIFESTATIONS

Generally non-specific

Symptoms


Local
Intermittent pain
Occasionally bleeding, obstruction, perforation

Systemic
Malaise, fever, weight loss.

Signs

Palpate
For palpable mass.

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INVESTIGATIONS

Imaging
CT scan
- characteristically shows a large homogenous mass
- Variable mural thickening, from marked with B-cell lymphoma to moderate with T-cell

Biopsy
Biopsy required for diagnosis
Either by endoscopy, CT-guided or laparoscopy / laparotomy.
Enables immunohistochemistry, flow-cytometry and cytogenetic and molecular evaluations.
--> Classification of lymphoma and optimal treatment strategy.

Staging
Bone marrow biopsy
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MANAGEMENT

Optimal treatment of GI lymphoma is quite poorly defined and is debated
Chemotherapy = variable cure rates.
- diffuse large cell responds, others eg anaplastic do not.

For localised early-stage lymphoma, surgical resection of all gross disease plays a critical role
- prevents complications such as perforation and obstruction
- improves prognosis

For advanced tumours, involving multiple organs, no role for surgery.

Medical
Low grade lymphoma
Long-term chemo - cyclophosphamide.

Operative
Pseudolymphoma
Resection
- histo reassures; shows mature germinal centers.

High grade

Resection then radioRx; debated.

Intra-operative staging

- needle biopsy of liver lobes
- biopsies of celiac and para-aortic nodes
- splenectomy if involved

Prognosis
Varies with subtype
5yr survival is ~50%
Male and age >75 also predict poorer survival.

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REFERENCES

Cameron 10th
Doherty