Hodgkin vs Non-Hodgkin Lymphoma on COMLEX: How to Tell Them Apart

The fastest way to separate Hodgkin from non-Hodgkin lymphoma on board exams is the cell on biopsy and the way the disease spreads. Hodgkin lymphoma shows Reed-Sternberg cells (large binucleate "owl eye" cells that are CD15 and CD30 positive), follows a bimodal age curve, and spreads in an orderly, contiguous fashion from one nodal group to the next. Non-Hodgkin lymphoma is a large family of B-cell and T-cell tumors with no Reed-Sternberg cells, a single peak in older adults, frequent extranodal disease, and noncontiguous spread. If the stem hands you a Reed-Sternberg cell, it's Hodgkin until proven otherwise.

Boards love this comparison because it integrates histology, epidemiology, and clinical behavior into one vignette. The trap is that both diseases share painless lymphadenopathy and B symptoms, so students who anchor on "swollen lymph nodes plus night sweats" can't split them. The discriminating data live in the biopsy description, the age in the stem, the pattern of nodal involvement, and the named translocation. Lock those in and these questions stop being a guess.

Why do boards confuse you with Hodgkin and non-Hodgkin lymphoma?

Both diseases open the same way: painless, rubbery lymphadenopathy, sometimes with fever, drenching night sweats, and weight loss. Those B symptoms show up in either category, so the opening sentence of the vignette rarely tells you which one you're looking at. That overlap is the whole point of the question.

The separators are histology, age, and spread pattern. Hodgkin lymphoma is defined by the Reed-Sternberg cell sitting in a background of reactive lymphocytes, eosinophils, and plasma cells. Non-Hodgkin lymphoma is a sheet of monoclonal malignant lymphocytes with no Reed-Sternberg cell in sight. Once you train yourself to look past the lymphadenopathy and hunt for the biopsy finding, the answer falls out.

Three axes crack almost every question in this differential:

1. Histology: Reed-Sternberg cell present (Hodgkin) or absent (non-Hodgkin)
2. Epidemiology: bimodal age curve (Hodgkin) versus a single peak in older adults (non-Hodgkin), plus any named risk factor like EBV, HIV, HTLV-1, or H. pylori
3. Spread and site: contiguous nodal spread with rare extranodal disease (Hodgkin) versus noncontiguous, often extranodal, frequently widespread disease (non-Hodgkin)

Hodgkin lymphoma: Reed-Sternberg cells and orderly spread

What Hodgkin lymphoma actually is

Hodgkin lymphoma is a B-cell malignancy in which the cancerous cell, the Reed-Sternberg cell, makes up only a small fraction of the tumor. Most of the mass is reactive immune cells recruited by cytokines the Reed-Sternberg cells secrete. The classic Reed-Sternberg cell is large, has abundant cytoplasm, and carries two mirror-image nuclei with prominent eosinophilic nucleoli, the "owl eye" look. On immunohistochemistry, classic Reed-Sternberg cells are CD15 and CD30 positive and usually CD20 negative.

The disease starts in a single nodal region, most often cervical or supraclavicular, and travels to contiguous nodal groups before going systemic. That predictable spread is why localized Hodgkin disease can be staged cleanly and treated with combination chemotherapy, sometimes with radiation to involved fields.

Board demographics and risk factors for Hodgkin lymphoma

The hallmark is a bimodal age distribution, with one peak in young adults (roughly 15 to 35) and a second peak after age 55. The young-adult peak is the one boards lean on hardest. Epstein-Barr virus is the classic associated agent, most tightly linked to the mixed cellularity subtype and to cases in immunocompromised patients. A prior history of infectious mononucleosis or HIV raises the risk.

Board histologic subtypes of Hodgkin lymphoma

COMLEX and USMLE both reward knowing the four classic subtypes and which one is most common.

A useful principle: the more lymphocytes and the fewer Reed-Sternberg cells, the better the prognosis. That single rule lets you rank the subtypes without rote memorization.

Board clinical features and workup for Hodgkin lymphoma

The high-yield stem is a young adult with painless cervical or supraclavicular adenopathy, drenching night sweats, unexplained weight loss, and fever. Two extra clues point hard at Hodgkin: Pel-Ebstein fever (a cyclical fever that rises and falls over days to weeks) and pain in an involved node after drinking alcohol. Neither is sensitive, but if a stem mentions either, it's steering you toward Hodgkin. A mediastinal mass on chest imaging in a young person fits nodular sclerosis especially well. Staging uses the Ann Arbor system, and treatment of classic disease is built around the ABVD chemotherapy regimen.

Non-Hodgkin lymphoma: many subtypes, scattered spread

What non-Hodgkin lymphoma actually is

Non-Hodgkin lymphoma is not one disease. It's a broad category of malignancies arising from B cells (roughly 85 percent) or T cells (the rest), each with its own genetics and behavior. There's no Reed-Sternberg cell. Instead the node or extranodal site is replaced by a monoclonal population of malignant lymphocytes. Because the malignant cells circulate, the disease spreads hematogenously and noncontiguously, skips around the body, and frequently involves extranodal sites like the gut, skin, central nervous system, and bone marrow. Many patients already have widespread disease at diagnosis.

That scattered behavior is the clinical mirror image of Hodgkin lymphoma. Where Hodgkin walks node to node, non-Hodgkin lymphoma jumps.

Board demographics and risk factors for non-Hodgkin lymphoma

Most non-Hodgkin lymphomas peak in older adults, although Burkitt and lymphoblastic types skew young. Immunosuppression is a major theme: HIV, post-transplant immunosuppression, and autoimmune disease all raise the risk. Several subtypes carry signature infectious or autoimmune associations that boards test directly, including EBV, HIV, HTLV-1, H. pylori, Sjogren syndrome, and Hashimoto thyroiditis.

Board high-yield non-Hodgkin subtypes

This is where most of the points live. Each subtype has a translocation, a buzzword, or an association that makes it identifiable.

You do not need every entity in the WHO classification for boards. You do need this short list cold, because the question usually hands you the translocation or the buzzword and asks you to name the tumor or the next step.

Board clinical features and workup for non-Hodgkin lymphoma

The presentation depends on the subtype and the site. A common pattern is painless lymphadenopathy in an older adult, with or without B symptoms, often plus an extranodal complaint: abdominal fullness, a skin lesion, or a neurologic deficit. Indolent types (like follicular) can wax and wane for years. Aggressive types (like diffuse large B-cell and Burkitt) grow fast and demand urgent treatment. Burkitt in particular can drive tumor lysis syndrome, so a stem with a fast-growing abdominal mass, high LDH, and rising uric acid and potassium is steering you there. Diagnosis rests on excisional lymph node biopsy and immunophenotyping, and management is subtype-specific, frequently including rituximab for CD20-positive B-cell disease.

Side-by-side comparison table

This is the table to drill until you can reproduce it from memory. If you can fill it in cold, you can answer most board questions on this differential in well under a minute.

How do you crack a lymphoma vignette in under a minute?

Read for the biopsy first, the demographics second, and the spread pattern third. Most of these stems hide the answer in one of those three places, and the lymphadenopathy and B symptoms at the top are just noise meant to slow you down. Five patterns carry most of the points:

1. Reed-Sternberg cell, owl-eye cell, or CD15/CD30 positive equals Hodgkin lymphoma. This is the single most reliable separator. If the histology line names it, you're done.

2. Young adult with a mediastinal mass and night sweats equals nodular sclerosis Hodgkin lymphoma. The mediastinal mass plus the young (often female) demographic is the classic nodular sclerosis fingerprint.

3. Fast-growing abdominal or jaw mass with starry-sky histology and tumor lysis equals Burkitt lymphoma. Add t(8;14) or c-myc to seal it. Endemic disease favors the jaw; sporadic disease favors the abdomen.

4. Gastric lymphoma that regresses after treating an infection equals H. pylori-associated MALT lymphoma. Treating the bug treats the tumor in early gastric MALT, which is a favorite "next step" answer.

5. Translocation plus behavior equals the named non-Hodgkin subtype. t(14;18) with indolent waxing-and-waning nodes is follicular; t(11;14) with CD5 positivity in an older man is mantle cell. The genetics are doing the work, not the adenopathy.

Students who internalize a structured framework like this stop missing integrated heme/onc questions, and that's exactly the kind of pattern drilling we build into the free Premeducated Skool community.

Common board pitfalls and how to avoid them

Pitfall 1: Anchoring on B symptoms. Fever, night sweats, and weight loss appear in both categories. They tell you a lymphoma is systemic, not whether it's Hodgkin or non-Hodgkin. Skip past them to the biopsy and the age.

Pitfall 2: Forgetting that the Reed-Sternberg cell is a B cell. It looks like its own creature, but the malignant Reed-Sternberg cell is B-cell derived. Boards sometimes test the cell of origin directly, and "B cell" is the answer even though classic Reed-Sternberg cells are usually CD20 negative.

Pitfall 3: Mixing up the translocations. t(14;18) is follicular (BCL2), t(8;14) is Burkitt (c-myc), and t(11;14) is mantle cell (cyclin D1). A quick memory hook: 8 and 14 for Burkitt because the c-myc story is the loudest one, and 11;14 for mantle cell because cyclin D1 controls the cell cycle.

Pitfall 4: Missing tumor lysis syndrome in Burkitt. A rapidly growing mass with high LDH, hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcemia is tumor lysis. Burkitt is the classic driver because it divides so fast. The board task is recognizing the metabolic emergency and starting hydration plus rasburicase or allopurinol.

Pitfall 5: Overlooking the H. pylori link in gastric MALT. When a stem describes a gastric lymphoma and asks for the next step, treating H. pylori can induce remission in early disease. Reflexively reaching for chemotherapy or surgery first is the trap.

Pitfall 6: Ignoring the immunosuppression theme in non-Hodgkin lymphoma. HIV, transplant immunosuppression, and autoimmune disease all raise non-Hodgkin risk, and EBV-driven lymphoma is common in these patients. If the stem plants immunosuppression, weight the differential toward non-Hodgkin disease.

Practice questions

Work through each stem with the answer choices covered, then check yourself against the explanation.

Question 1

A 24-year-old woman presents with a 2-month history of painless neck swelling, drenching night sweats, and a 6 kg unintentional weight loss. She reports that an involved node becomes painful after she drinks alcohol. A chest radiograph shows a large anterior mediastinal mass. Excisional biopsy of a cervical lymph node reveals scattered large binucleate cells with prominent eosinophilic nucleoli set in broad bands of fibrous tissue; these cells stain positive for CD15 and CD30. Which of the following is the most likely diagnosis?

A. Burkitt lymphoma B. Diffuse large B-cell lymphoma C. Follicular lymphoma D. Nodular sclerosis Hodgkin lymphoma E. Mantle cell lymphoma

Correct answer: D

This is classic Hodgkin lymphoma, nodular sclerosis subtype. The binucleate "owl eye" cells that are CD15 and CD30 positive are Reed-Sternberg cells, which define Hodgkin disease. The young woman, the anterior mediastinal mass, and the broad collagen bands all point specifically to the nodular sclerosis subtype, the most common form of Hodgkin lymphoma. Alcohol-induced nodal pain and B symptoms further support Hodgkin disease. The non-Hodgkin options (A, B, C, and E) lack Reed-Sternberg cells and would show a monoclonal lymphocyte population rather than the described histology, so each is wrong.

Question 2

An 8-year-old boy in equatorial Africa is brought in for a rapidly enlarging mass of the jaw and face that has doubled in size over 2 weeks. Laboratory studies show a markedly elevated lactate dehydrogenase, hyperuricemia, hyperkalemia, and hyperphosphatemia. Biopsy reveals sheets of intermediate-sized lymphocytes with numerous interspersed pale macrophages, producing a "starry sky" appearance, and a very high proliferation index. Which of the following genetic abnormalities is most likely responsible?

A. c-myc activation from t(8;14) B. Cyclin D1 overexpression from t(11;14) C. BCL2 overexpression from t(14;18) D. Retinoic acid receptor fusion from t(15;17) E. BCR-ABL fusion from t(9;22)

Correct answer: A

This is endemic Burkitt lymphoma, a highly aggressive B-cell non-Hodgkin lymphoma. The "starry sky" histology (sheets of malignant lymphocytes dotted with tingible-body macrophages clearing apoptotic debris) and the very high proliferation index are characteristic. The driving lesion is t(8;14), which places the c-myc oncogene under the immunoglobulin heavy chain promoter and drives relentless proliferation (A is correct). The jaw mass in an African child is the endemic, EBV-associated form. The fast turnover explains the tumor lysis pattern of high LDH, uric acid, potassium, and phosphate. t(11;14) is mantle cell (B), t(14;18) is follicular (C), t(15;17) is acute promyelocytic leukemia (D), and BCR-ABL is chronic myeloid leukemia (E), so each of those is wrong.

Frequently asked questions about Hodgkin vs non-Hodgkin lymphoma

What is the single most reliable way to tell Hodgkin from non-Hodgkin lymphoma?

Look for the Reed-Sternberg cell on biopsy. It's the large binucleate "owl eye" cell that stains CD15 and CD30 positive and sits in a reactive background of lymphocytes and eosinophils. If the histology line names it, the diagnosis is Hodgkin lymphoma. Non-Hodgkin lymphoma has no Reed-Sternberg cell and instead shows a monoclonal sheet of malignant B or T lymphocytes. Everything else (age, spread pattern, translocation) supports the call, but the Reed-Sternberg cell is the definitive separator.

Why does Hodgkin lymphoma have a better reputation on boards than non-Hodgkin lymphoma?

Hodgkin lymphoma spreads in an orderly, contiguous fashion from one nodal group to the adjacent one, so it's often caught while still localized and is highly treatable, frequently curable even at advanced stage. Non-Hodgkin lymphoma spreads hematogenously and noncontiguously, involves extranodal sites, and is often widespread at diagnosis. That said, non-Hodgkin prognosis is highly variable by subtype: indolent follicular lymphoma behaves very differently from aggressive Burkitt or diffuse large B-cell lymphoma. Boards reward knowing both the general rule and the subtype exceptions.

Which translocations do I actually need for non-Hodgkin lymphoma?

Three carry most of the points. t(14;18) overexpresses BCL2 and defines follicular lymphoma, an indolent disease with waxing and waning adenopathy. t(8;14) places c-myc under the immunoglobulin promoter and defines Burkitt lymphoma, with "starry sky" histology and tumor lysis risk. t(11;14) overexpresses cyclin D1 and defines mantle cell lymphoma, which is CD5 positive and aggressive. Memorize the translocation, the gene, and one behavioral buzzword for each, because the question usually gives you one and asks for the others.

How is EBV connected to lymphoma on board exams?

Epstein-Barr virus links to several lymphomas, which is why boards test it across the differential. In Hodgkin lymphoma, EBV associates most strongly with the mixed cellularity subtype and with cases in immunocompromised patients. In non-Hodgkin lymphoma, EBV drives endemic (African) Burkitt lymphoma and many lymphomas arising in HIV and post-transplant patients. A stem that mentions prior mononucleosis, HIV, or transplant immunosuppression is often steering you toward an EBV-associated lymphoma, so let that detail raise your suspicion.

Why does treating H. pylori matter for a gastric lymphoma question?

Gastric MALT lymphoma, a marginal zone non-Hodgkin lymphoma, is frequently driven by chronic Helicobacter pylori infection. In early-stage gastric MALT, eradicating H. pylori with antibiotics and a proton pump inhibitor can induce regression of the tumor itself. That makes "treat H. pylori" the correct next step on many board stems, ahead of chemotherapy or surgery. It's one of the cleaner examples on boards of an infection directly driving a cancer, so the link is heavily tested.

Are Hodgkin and non-Hodgkin lymphoma tested differently on COMLEX versus USMLE?

Both exams test the same core comparison, but with slightly different emphasis. COMLEX leans on the classic clinical vignette: the young adult with a mediastinal mass and night sweats for Hodgkin, the African child with a jaw mass for Burkitt, the gastric lesion that responds to H. pylori treatment for MALT. USMLE Step 1 adds more molecular depth, asking about the specific translocation, the oncogene, and the immunophenotype (CD15 and CD30 for Reed-Sternberg cells, CD20 for B-cell non-Hodgkin disease). If you can fill out the comparison table from memory, you'll handle questions on either exam.

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