Pancreatic lymphoma is most commonly a B-cell subtype of non-Hodgkin lymphoma
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Epidemiology
Pancreatic lymphoma is typically seen in middle-aged patients with a mean age of around 55 years old and is more common in immunocompromised patients.
Clinical presentation
Symptoms are often non-specific but may include 1:
- abdominal pain ~ 85%
- mass ~ 60%
- weight loss ~ 50%
- obstructive jaundice ~ 40% of cases
- acute pancreatitis 10%
The classic B-symptoms of non-Hodgkin lymphoma (i.e. fever, weight loss, night sweats) are present in only 2% of cases 1,2.
Pathology
Etiology
It is classified as either primary or secondary:
- primary pancreatic lymphoma is a rare extranodal manifestation of any histopathologic subtype of B-cell non-Hodgkin lymphoma, representing <2% of extranodal lymphomas and 0.5% of pancreatic tumors 1,2
- secondary lymphoma: found in 30% of non-Hodgkin lymphoma patients with widespread disease, it is the dominant form and is the result of direct extension from peripancreatic lymphadenopathy 1
Location
Two morphologic patterns of pancreatic lymphoma are recognized 1:
- focal form: occurs in the pancreatic head in 80% of cases and has a mean size of 8 cm
- diffuse form: infiltrative, leading to glandular enlargement and poor definition, features that can simulate the appearance of acute pancreatitis
Radiographic features
CT
- minimal enhancement
- peripancreatic lymph node enlargement
- it typically has uniform low attenuation
- diffuse enlargement (diffuse form) may simulate acute pancreatitis
- encasement of the peripancreatic vessels may occur; vascular invasion is less common in lymphoma than in adenocarcinoma 1-2
MRI
- focal form: low signal intensity on T1-weighted images and intermediate signal intensity on T2-weighted images (slightly higher signal intensity than the pancreas but lower signal intensity than fluid), and shows faint contrast enhancement 1
- diffuse form: low signal intensity on T1- and T2-weighted MR images and shows homogeneous contrast enhancement, although small foci of reduced or absent enhancement are sometimes seen 1
Treatment and prognosis
Percutaneous or endoscopic core biopsy should be performed to establish the diagnosis 2.
Pancreatic lymphoma carries a better prognosis than adenocarcinoma because first-line treatment with chemotherapy is generally effective in producing long-term disease regression or remission. Surgery is not required in most cases 1.
Using complex treatment approaches, cure rates of up to 30% are reported for patients with primary pancreatic lymphoma. This prognosis is much better than the dismal 5% 5-year survival rate in patients with pancreatic adenocarcinoma 2.
Differential diagnosis
Imaging differential considerations include
For a diffuse bulkiness to the pancreas consider