High Grade B cell Lymphoma with MYC and BCL2 Rearrangements: Understanding Your Pathology Report

by Jason Wasserman MD PhD FRCPC
April 16, 2026

High-grade B cell lymphoma with MYC and BCL2 rearrangements — also called diffuse large B cell lymphoma (DLBCL) with MYC and BCL2 rearrangements, or informally “double-hit lymphoma” — is an aggressive blood cancer that starts in B cells. These white blood cells help the body fight infections. The name refers to two specific genes, MYC and BCL2, that have each undergone a rearrangement. A rearrangement is a type of genetic change in which a segment of DNA breaks off from its normal location on a chromosome and reattaches somewhere else — sometimes next to a different gene that switches it on inappropriately. In this disease, rearrangements in both MYC and BCL2 occur at the same time, and it is this combination that makes the cancer behave more aggressively than most other lymphomas. MYC is a gene that drives rapid cell division, while BCL2 is a gene that prevents cells from dying when they should. Together, these changes cause the lymphoma cells to multiply quickly and resist the normal mechanisms that would otherwise eliminate them.

This cancer requires prompt diagnosis and treatment with more intensive chemotherapy regimens than those used for standard diffuse large B cell lymphoma. This article will help you understand the findings in your pathology report, what each term means, and why it matters for your care.

What are the symptoms?

The symptoms of high-grade B cell lymphoma with MYC and BCL2 rearrangements are similar to those of other aggressive lymphomas but tend to develop and worsen rapidly. The most common finding is a quickly growing lump or mass — usually a swollen lymph node in the neck, armpit, or groin — though the lymphoma can also arise in the abdomen, chest, bone marrow, or other extranodal sites (tissues outside the lymph nodes).

Many people experience general symptoms called B symptoms: unexplained fever, drenching night sweats, and unintentional weight loss of more than 10% of body weight over six months. Fatigue and loss of appetite are common. Because this lymphoma grows quickly, symptoms can escalate over days to weeks. A notably high LDH (lactate dehydrogenase) blood level — a marker of rapid cell turnover — is frequently present at diagnosis and often prompts urgent investigation. Central nervous system (CNS) involvement, either at diagnosis or as a site of relapse, is more common in this subtype than in standard diffuse large B cell lymphoma, and symptoms such as headache, confusion, or neurological changes should be reported promptly to your care team.

What causes high-grade B cell lymphoma with MYC and BCL2 rearrangements?

This lymphoma is caused by two simultaneous acquired genetic rearrangements — changes that occur in a B cell during a person’s lifetime rather than being inherited. The first involves the MYC gene, and the second involves the BCL2 gene. Understanding what each rearrangement does and why their combination is so dangerous helps explain why this lymphoma is more aggressive than most.

MYC is a gene that normally acts as a master switch for cell growth — it turns on dozens of other genes that push cells to divide and multiply. In normal cells, MYC is tightly controlled and only switches on when growth is needed. In high-grade B cell lymphoma, a rearrangement moves MYC next to a highly active region of the genome — most commonly the immunoglobulin heavy chain gene, which is permanently switched on in B cells. As a result, MYC is driven into continuous, uncontrolled activity, causing the lymphoma cells to divide at an extremely rapid rate. Virtually all MYC rearrangements in this disease involve a translocation called t(8;14), though variant translocations involving chromosomes 2 or 22 also occur.

BCL2 is a gene that produces a protein whose job is to prevent cells from dying through the normal process of programmed cell death (apoptosis). In healthy tissue, when a cell becomes damaged or abnormal, BCL2 activity decreases, allowing the cell to die and be cleared away. In this lymphoma, a rearrangement — typically t(14;18), the same translocation found in classic follicular lymphoma — places BCL2 under the control of the same immunoglobulin gene that drives MYC, resulting in permanently elevated BCL2 production. The lymphoma cells cannot die even when they should.

The combination of these two rearrangements creates a uniquely dangerous situation: the lymphoma cells divide rapidly because of MYC and simultaneously resist death because of BCL2. This dual effect makes the cancer more aggressive than when either rearrangement occurs alone, and it also makes the cells more resistant to some standard chemotherapy drugs, which often work by triggering programmed cell death.

No specific environmental or lifestyle factor has been identified as a cause of this disease. In most cases, the rearrangements arise by chance during the normal process of B cell development, in which B cells must rearrange their immunoglobulin genes. This process occasionally goes wrong and moves other genes into proximity with these powerful regulatory regions.

How is the diagnosis made?

The diagnosis requires tissue examination under the microscope, combined with specialized genetic testing. A biopsy — ideally an excisional biopsy of an affected lymph node — provides the tissue. The pathologist examines the cells and performs immunohistochemistry (IHC) to identify the protein profile of the lymphoma cells. FISH (fluorescence in situ hybridization) is then used to detect the MYC and BCL2 gene rearrangements that define this disease. FISH is essential because these rearrangements cannot be identified by immunohistochemistry alone. The diagnosis cannot be made without FISH confirmation of both rearrangements.

Once the diagnosis is established, a thorough staging evaluation is performed, including whole-body PET/CT imaging, blood tests (including LDH and full blood count), and bone marrow biopsy. Because CNS involvement is more common in this disease than in standard diffuse large B cell lymphoma, a lumbar puncture (spinal tap) to examine the cerebrospinal fluid for lymphoma cells is frequently part of the initial evaluation.

What does this lymphoma look like under the microscope?

Under the microscope, high-grade B cell lymphoma with MYC and BCL2 rearrangements shows a diffuse growth pattern — the lymphoma cells spread in flat sheets through the lymph node or tissue rather than forming compact clusters. This infiltrative growth replaces the normal tissue architecture. The cells are large, with prominent nuclei and large nucleoli (dense structures within the nucleus).

The microscopic appearance can vary considerably between cases and may resemble several other aggressive lymphomas, which is why genetic testing is essential. Three main appearances are seen:

DLBCL-like appearance — The most common pattern. Large cells with round or oval nuclei, several small nucleoli, and actively dividing cells (mitotic figures) throughout. Necrosis (areas of dead cells) is common. In some cases, scattered pale macrophages (immune cells that remove cellular debris) are distributed among the dark lymphoma cells, creating a pattern called “starry sky” — an appearance that in this context reflects the very high rate of cell death and turnover.
Burkitt-like appearance — Some cases have medium to large cells that closely resemble those seen in Burkitt lymphoma, with a very high proliferation rate and a prominent starry-sky pattern. These cases are sometimes described as having an “intermediate” morphology between DLBCL and Burkitt lymphoma.
Blastoid appearance — A minority of cases contain cells that resemble immature B cells, with finer chromatin (the material inside the nucleus appears lighter and less coarse than in typical DLBCL). This blastoid variant is associated with particularly aggressive behavior.

Pathologists cannot reliably distinguish high-grade B cell lymphoma with MYC and BCL2 rearrangements from standard diffuse large B cell lymphoma based on microscopic appearance alone — the morphology overlaps substantially. FISH testing is required to confirm the diagnosis.

Immunohistochemistry results

Immunohistochemistry (IHC) confirms the B cell nature of the lymphoma, establishes the cell of origin subtype, and identifies MYC and BCL2 protein expression. The typical profile is described below.

CD20 — Positive in most cases. Confirms B cell origin and is the target of rituximab used in treatment.
PAX5 — Positive. Confirms B cell lineage.
CD10 — Positive in approximately 88–98% of cases. The high rate of CD10 expression reflects the germinal center origin of most cases and classifies the majority as the GCB (germinal center B cell-like) subtype by the Hans algorithm.
BCL6 — Positive in approximately 75–89% of cases.
BCL2 protein — Positive in approximately 90–95% of cases. Strong BCL2 protein expression is expected due to the BCL2 gene rearrangement, which drives its overproduction. BCL2 positivity here is more uniform and intense than in typical non-rearranged DLBCL.
MYC protein — Positive in approximately 78–86% of cases. Because both MYC and BCL2 proteins are expressed, most cases are dual expressors by immunohistochemistry. However, it is important to understand that protein expression detected by IHC is not the same as gene rearrangement detected by FISH — some tumors express both proteins without having gene rearrangements (those are double-expressor DLBCL, not double-hit lymphoma), and conversely, some tumors with confirmed gene rearrangements may have lower-than-expected protein expression. The diagnosis requires FISH, not protein expression alone.
Ki-67 — High, typically 70–100%. This extremely high proliferation index reflects the relentless MYC-driven cell division and is one of the highest Ki-67 values seen in any lymphoma.
CD34 — Negative. TdT — Negative. The absence of these markers of immaturity helps exclude B-lymphoblastic lymphoma, which can occasionally appear similar.

FISH testing and the role of gene rearrangements

FISH is the definitive test for confirming the diagnosis. It detects whether the MYC and BCL2 genes have been physically moved from their normal positions on chromosomes to new locations. The diagnosis of high-grade B cell lymphoma with MYC and BCL2 rearrangements requires both rearrangements to be confirmed by FISH.

The MYC rearrangement is detected first. If MYC is rearranged, BCL2 is then tested. If BCL2 is also rearranged, the diagnosis is confirmed. Some cases also carry a BCL6 rearrangement in addition to MYC and BCL2 — these are sometimes called triple-hit lymphomas and tend to be particularly aggressive. BCL6 rearrangement without BCL2 rearrangement (i.e., MYC + BCL6 but no BCL2) does not fulfill the criteria for this diagnosis. It is instead classified as diffuse large B cell lymphoma with MYC and BCL6 rearrangements — a related but distinct entity.

A technical note: MYC rearrangements at unusual chromosomal breakpoints or involving small DNA insertions can occasionally be missed by standard FISH probes. If clinical suspicion is high and standard FISH is negative, additional testing with different probe types (fusion probes) or comprehensive genomic profiling may be warranted. Your pathologist will note in the report which probes were used and whether any technical limitations apply.

How is this disease different from standard DLBCL?

High-grade B cell lymphoma with MYC and BCL2 rearrangements is classified separately from standard diffuse large B cell lymphoma because it is substantially more aggressive and responds less well to the treatment regimen — R-CHOP — that is standard for DLBCL. Several key differences are worth understanding:

In standard DLBCL, approximately 60–70% of patients achieve long-term remission with R-CHOP. In high-grade B cell lymphoma with MYC and BCL2 rearrangements, long-term remission rates with R-CHOP are significantly lower — approximately 25–40% in most published series. This is why more intensive regimens are typically recommended.

It is also important not to confuse this disease with double-expressor DLBCL, in which both MYC and BCL2 proteins are expressed by immunohistochemistry without underlying gene rearrangements. Double-expressor DLBCL has a worse prognosis than standard DLBCL but is still classified as DLBCL and may be treated with standard R-CHOP or modified regimens. High-grade B cell lymphoma with MYC and BCL2 rearrangements — defined by confirmed gene rearrangements on FISH — is a distinct, more aggressive entity. Your pathology report will specify whether the diagnosis is based on gene rearrangements (FISH) or protein expression (IHC) — this distinction matters for treatment planning.

Staging

Staging follows the Lugano classification, based on PET/CT imaging and bone marrow biopsy, using the same stage I–IV framework as other lymphomas. Most patients present with advanced-stage (stage III–IV) disease at diagnosis, often with multiple nodal and extranodal sites involved and an elevated LDH. CNS involvement — either leptomeningeal disease (spread to the membrane and fluid around the brain and spinal cord) or parenchymal brain involvement — is more common than in standard DLBCL, occurring at diagnosis or as relapse in approximately 10–15% of patients, which is why CNS evaluation with lumbar puncture is typically performed at staging.

What is the prognosis?

High-grade B cell lymphoma with MYC and BCL2 rearrangements has a less favorable prognosis than standard diffuse large B cell lymphoma, particularly when treated with standard R-CHOP. With intensive induction chemotherapy (discussed below), approximately 40–60% of patients achieve a complete response, and long-term remission rates in patients who receive intensive therapy followed by consolidation range from approximately 40–55% in published clinical series. These figures continue to improve as treatment approaches evolve.

Factors associated with worse prognosis include advanced stage at diagnosis, high IPI (International Prognostic Index) score, CNS involvement, and failure to achieve complete remission after initial treatment. The presence of a BCL6 rearrangement in addition to MYC and BCL2 (triple-hit) may be associated with even worse outcomes, though the data are limited. Achieving a complete metabolic response on PET/CT after treatment is the strongest predictor of long-term remission.

The prognosis for patients who relapse after intensive first-line therapy is generally poor, with lower response rates to salvage regimens than are seen in relapsed standard DLBCL. Referral to experienced lymphoma centers and clinical trial enrollment are particularly important in this setting.

What happens after the diagnosis?

Because of the aggressive nature of this disease, treatment typically begins promptly — within days to a week or two of diagnosis. Standard R-CHOP chemotherapy is generally considered insufficient for this disease. The most widely used intensive regimen is DA-EPOCH-R (dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin, plus rituximab), which allows real-time dose adjustment based on blood count recovery between cycles. In several clinical series and retrospective studies, DA-EPOCH-R has shown higher complete response rates than R-CHOP in this disease, and it is the regimen most commonly recommended in North America for fit patients. Other intensive induction regimens used in some centers include R-HyperCVAD/MA (rituximab plus hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone alternating with methotrexate and cytarabine) or R-CODOX-M/IVAC.

CNS prophylaxis — treatment to prevent or detect early spread to the central nervous system — is a standard component of management. This typically involves intrathecal chemotherapy (medication delivered into the spinal fluid via lumbar puncture) or high-dose systemic methotrexate, which penetrates the blood-brain barrier. The specific approach varies by center and clinical risk factors.

For patients who achieve a complete remission after induction, consolidation with autologous stem cell transplantation (collecting and reinfusing the patient’s own stem cells after intensive conditioning chemotherapy) has been used at some centers for high-risk patients. However, evidence for its benefit in this disease, specifically compared to continued observation in complete responders, remains debated.

For relapsed or refractory disease, options include salvage chemoimmunotherapy, CAR T cell therapy (axicabtagene ciloleucel or lisocabtagene maraleucel), bispecific antibodies (epcoritamab, glofitamab), or clinical trials. Response rates to salvage therapy are generally lower than in relapsed standard DLBCL, making clinical trial participation particularly valuable when available.

Questions to ask your doctor

Did FISH confirm both MYC and BCL2 rearrangements, and was BCL6 also tested?
Is my lymphoma triple-hit (MYC, BCL2, and BCL6 all rearranged), and does that change my treatment plan?
Was my LDH elevated at diagnosis, and what is my IPI score?
Has the lymphoma been assessed for CNS involvement? Was a lumbar puncture performed?
What treatment regimen are you recommending — DA-EPOCH-R or another intensive regimen — and why?
Will I receive CNS prophylaxis, and in what form?
How many treatment cycles will I need, and how will response be assessed?
Is autologous stem cell transplantation being considered as consolidation after remission?
What symptoms should prompt me to contact you urgently during treatment?
What happens if the lymphoma does not respond to or comes back after treatment?
Are there clinical trials available for my situation that I should consider?