Lymphoma for Radiology Board Review Part 2
Review of key concepts of lymphoma for radiology board examinations. Prepare to succeed!
Show Notes/Study Guide:
The most common extranodal site for non-Hodgkin’s lymphoma is what organ?
The stomach is the most common extranodal site of NHL.
What are typical imaging features of gastric lymphoma?
Gastric wall thickening without gastric outlet obstruction, even when extensive wall thickening is present. Note that primary gastric lymphoma is mucosa-associated lymphoma tissue (MALT) as stomach has no intrinsic lymphoid tissue. Both gastric lymphoma and gastric adenocarcinoma can cross the pylorus into the duodenum. Gastric lymphoma can also have a linitis plastica (leather bottle) appearance which can also be seen with infiltrative metastases from lung, breast, or other cancers. Compared to lymphoma, gastric carcinoma is more likely to present with a focal mass and gastric outlet obstruction. At a more detailed level, gastric lymphoma is typically either extranodal marginal zone lymphoma which has homogeneous wall thickening with perigastric lymphadenopathy or diffuse large B cell lymphoma which has wall thickening typically >4 cm with lymphadenopathy and possible cavitation.
What is most common—gastric adenocarcinoma or gastric lymphoma?
Gastric adenocarcinoma comprises about 95% of gastric cancers and lymphoma comprises the majority of the remaining 5%. GIST also occurs in the stomach and typically has characteristic smooth margins without lymphadenopathy.
Does H. pylori infection increase risk of gastric lymphoma?
Yes, H. pylori raises risk of both gastric adenocarcinoma and gastric lymphoma. Chronic H. pylori infection causes gastritis and over time this inflammation causes the mucosa to gradually acquire lymphoid tissue (MALT) that is at risk for monoclonal proliferation. Interestingly, low grade MALT lymphoma can sometimes be cured with H. pylori eradication. If H. pylori is untreated, you can progress from low-grade to aggressive gastric lymphomas such as diffuse large B cell lymphoma.
What is a classic appearance for mesenteric lymphoma?
Confluent lobulated homogeneous soft tissue masses that encase mesenteric vessels. This has been termed the sandwich sign (soft tissue masses sandwiching the mesenteric vessels). With mesenteric lymphoma you can see fat between the mesenteric mass. Mesenteric mass(es) may distort surrounding structures but does not occlude. NHL most common.
What is misty mesentery and is this a sign of potential lymphoma?
Misty mesentery manifests as fat stranding in the central mesenteric fat. Misty mesentery is a sign of lymphatic insufficiency and is most seen in middle aged males and is typically stable over time and idiopathic, inflammatory, or related to portal hypertension. However, if you see misty mesentery and abnormal lymph nodes, this is suspicious for lymphoma. Misty mesentery can also less commonly result from lymphatic infiltration from a GI malignancy.
What is the deal with Burkitt lymphoma?
Burkitt lymphoma is a very aggressive B cell lymphoma (can double in size in 24 hours) that has early metastases. Unfortunately, this is the most common type of NHL in kids but fortunately children have a good prognosis with appropriate chemotherapy. Adults, however, have a worse prognosis. Burkitt lymphoma is much more common in boys and in Africa so if you see an aggressive appearing lymphoma with widespread manifestation of disease in a young African boy on a board exam question you need to consider Burkitt lymphoma. Endemic Burkitt lymphoma in Africa is linked to Epstein-Barr virus infection and/or malaria infections. Can also happen with HIV or immunosuppression to include post-organ transplantation.
What are B symptoms?
B symptoms are fever, night sweats, and weight loss (unintentional loss of >10 % body weight in six months). Lymphoma commonly presents with B symptoms so look for these in a question stem on your board exams. This results from elevated inflammatory cytokines.
Do B symptoms have prognostic implications?
Yes, if B symptoms are present this generally predicts poorer prognosis for lymphoma patients. Under the Lugano classification system, lymphoma is staged higher if B symptoms are present.
What is the Lugano classification system for staging of lymphoma?
Lugano stages lymphoma based on two main divisions: limited disease or advanced disease. You can look up the details elsewhere, but limited disease is basically lymphoma only a few lymph nodes on the same side of the diaphragm and advanced disease has lymph nodes on both sides of the diaphragm. Limited disease is stage 1 and 2 and advanced disease is stage 3 and 4.
Can you have stage 4 lymphoma without having lymph node involvement?
Yes, stage 4 may or may not have lymph node involvement of disease but requires diffuse involvement of at least one extranodal organ or extranodal disease that can’t be treated with radiation therapy.
What is the size cutoff in the Lugano classification for a lymph node to be considered as bulky disease?
10 cm. If a lymph node is >10 cm in diameter this is considered bulky disease.
What is more common, Hodgkin lymphoma or non-Hodgkin lymphoma?
Non-Hodgkin lymphoma is more common and comprises about 2/3 of lymphoma cases with Hodgkin lymphoma comprising 1/3 of lymphoma cases.
True or false? Hodgkin lymphoma is curable in most cases.
True. Hodgkin’s lymphoma is curable in about 90% of cases.
What is the pathologic hallmark of Hodgkin’s lymphoma?
Reed Sternberg cells are the histologic hallmark of Hodgkin’s lymphoma.
What are classic imaging manifestations of Hodgkin’s disease?
Hodgkin’s lymphoma typically manifests as lymphadenopathy that starts in the chest, axilla, and/or neck. Extranodal disease is not common. However, in advanced cases, any organ/tissue may be involved. When extranodal disease is present, this may often be seen in the bones (lytic early and blastic later) followed by the lungs (may see direct extension from hilar lymphadenopathy into the pulmonary parenchyma). Look for anterior vertebral body erosions from paravertebral lymphadenopathy and/or an ivory vertebra (single high density vertebral body—differential considerations include other metastatic disease, TB, Paget disease).
What entities are part of the non-Hodgkin lymphoma family?
NHL is a catch-all for everything that is not Hodgkin’s lymphoma. This includes Burkitt lymphoma, mantle cell lymphoma, follicular lymphoma, T- and Nk-cell lymphomas, and post-transplant lymphoproliferative disorders.
