Plasmablastic lymphoma – Diagnostics – Overview of Information and Clinical Research

Plasmablastic lymphoma is a rare and aggressive form of lymphoma that requires careful diagnostic testing to identify accurately. Because its features can overlap with other blood cancers, doctors use multiple specialized tests to confirm the diagnosis and determine if someone is suitable for treatment, including enrollment in clinical trials.

Introduction: Who Should Seek Diagnostic Testing

People who might need diagnostic testing for plasmablastic lymphoma typically present with certain warning signs that should prompt medical attention. Anyone experiencing rapidly growing masses or lumps in their mouth, digestive system, or lymph nodes should consider seeking medical evaluation. These growths might appear as soft tissue masses that can be painful, ulcerating, or even bleeding in some cases.^[1]

Certain groups of people should be especially vigilant about seeking diagnostics. Individuals living with HIV are at higher risk, as plasmablastic lymphoma is strongly associated with HIV infection. About two-thirds of people diagnosed with this condition are HIV-positive.^[2] Additionally, people who have received organ transplants or those with weakened immune systems due to autoimmune disorders or other conditions should monitor for unusual symptoms. Even elderly adults who appear to have normal immune function can develop this disease, so age should not discourage someone from seeking evaluation.^[3]

If you notice unexplained lumps in your mouth, jaw, or digestive tract, especially if they grow quickly, it’s advisable to consult a doctor promptly. Other symptoms that warrant investigation include persistent pain in the digestive system, blood in stool, nosebleeds accompanied by sinus inflammation, or any unusual growths under the skin. Some people may also experience what doctors call B symptoms—these include drenching night sweats that soak through bedding, unexplained fever, and significant weight loss without trying. These symptoms are more commonly seen in people with HIV infections.^[2]

⚠️ Important

Plasmablastic lymphoma is most commonly found outside the lymph nodes, particularly in the mouth or digestive system. Disease that only affects lymph nodes without involving other areas of the body is quite rare. This unusual pattern means that traditional signs of lymphoma, like swollen lymph nodes, may not always be present, making it crucial to pay attention to other symptoms.^[1]

Classic Diagnostic Methods

Diagnosing plasmablastic lymphoma is challenging because it shares features with other serious blood cancers. The diagnostic process typically begins with a physical examination where doctors assess any visible or palpable masses and ask about symptoms. If lymphoma is suspected, several specialized tests are necessary to confirm the diagnosis and distinguish plasmablastic lymphoma from similar conditions.^[2]

Histologic Evaluation and Biopsy

The cornerstone of diagnosing plasmablastic lymphoma is histologic evaluation, which means examining tissue samples under a microscope to look at the structure and appearance of cells. To obtain this tissue, doctors perform a biopsy—a procedure where a small sample of the suspicious mass or tumor is removed for analysis. The biopsy can be taken from various locations depending on where the disease appears, such as the oral cavity, lymph nodes, gastrointestinal tract, or skin.^[1]

When pathologists examine the tissue under a microscope, they look for specific characteristics. Plasmablastic lymphoma cells are large and resemble cells called immunoblasts or plasmablasts—these are cells in the process of transforming from infection-fighting B-cells into mature plasma cells. The malignant cells in plasmablastic lymphoma have stopped this transformation midway and instead multiply out of control.^[4]

Immunophenotyping

Immunophenotyping is a specialized laboratory technique that identifies proteins on the surface and inside cells. This test is crucial for plasmablastic lymphoma because it helps distinguish it from other lymphomas. The disease has a very specific pattern of protein expression that acts like a fingerprint for identification.^[1]

In plasmablastic lymphoma, the cancer cells typically show a plasma cell-like pattern. This means they express proteins usually found on plasma cells, such as CD38 and CD138, rather than proteins typically found on B-cells, like CD20. Testing usually reveals that CD20 is weakly positive or completely negative, which is unusual for most B-cell lymphomas. Other markers that may be positive include CD79a, EMA (epithelial membrane antigen), and IRF4/MUM1. The cells also show expression of cytoplasmic immunoglobulins, most commonly IgG along with either kappa or lambda light chains.^[5]

The Ki67 proliferation index is another important measurement. This marker indicates how quickly cells are dividing and multiplying. In plasmablastic lymphoma, the Ki67 index is usually very high, reflecting the aggressive, fast-growing nature of the disease.^[5]

Genetic Testing

Genetic testing adds another layer of information that helps confirm the diagnosis. One of the most important genetic features of plasmablastic lymphoma is MYC translocation, a rearrangement of genetic material involving the MYC gene. This abnormality is more common in cases where the cells are infected with Epstein-Barr virus (EBV). Doctors also look for clonal immunoglobulin heavy chain (IgH) light chain rearrangement, which demonstrates that the cancer cells all originated from a single abnormal cell.^[5]

Testing for EBV is particularly important. About two out of three people with plasmablastic lymphoma have evidence of EBV infection in their cancer cells. The presence of EBV can be detected through a test for EBV-encoded small RNAs (EBER), which shows whether the virus is present in the tumor tissue.^[2]

Additional Diagnostic Tests

Beyond examining the tumor itself, doctors typically order several other tests to understand the extent of the disease and assess overall health. Blood tests can reveal abnormalities in blood cell counts and provide information about organ function, particularly the liver and kidneys. Testing for HIV status is crucial, as the disease behaves differently in HIV-positive versus HIV-negative individuals.^[4]

Imaging studies help determine how widely the cancer has spread. These might include CT scans (computed tomography), PET scans (positron emission tomography), or MRI (magnetic resonance imaging). Because plasmablastic lymphoma commonly affects the gastrointestinal system, doctors may recommend an endoscopy—a procedure where a flexible tube with a camera is inserted to view the inside of the digestive tract.^[2]

A bone marrow biopsy may also be performed to check whether the lymphoma has spread to the bone marrow. This involves taking a small sample of bone marrow, usually from the hip bone, using a special needle. The sample is then examined under a microscope for cancer cells.^[3]

Distinguishing from Similar Conditions

One of the biggest challenges in diagnosing plasmablastic lymphoma is distinguishing it from other cancers that look similar under the microscope. The disease shares features with plasmablastic myeloma (also called plasma cell myeloma), which is a different type of cancer. Both conditions involve cells with plasma cell characteristics, but they are treated differently and have different prognoses.^[1]

Other conditions that must be ruled out include anaplastic lymphoma kinase-positive large B-cell lymphoma, human herpesvirus 8-positive diffuse large B-cell lymphoma, and primary effusion lymphoma. Each of these has its own distinct features, but the overlapping characteristics make diagnosis complex. This is why multiple tests—histology, immunophenotyping, and genetic studies—are typically needed together to reach a definitive diagnosis.^[3]

⚠️ Important

Plasmablastic lymphoma can be difficult to diagnose because it shares overlapping features with several other blood cancers. A correct diagnosis requires multiple specialized tests working together. If you’re undergoing evaluation for suspected plasmablastic lymphoma, don’t be surprised if doctors order several different tests—this thoroughness is necessary to ensure accurate identification and appropriate treatment planning.^[1]

Diagnostics for Clinical Trial Qualification

When someone is being considered for enrollment in a clinical trial for plasmablastic lymphoma, additional standardized testing may be required beyond the basic diagnostic workup. Clinical trials have specific criteria that participants must meet to ensure the study produces reliable results and that participants are suitable for the experimental treatment being tested.

Staging and Risk Assessment

Most clinical trials require detailed staging information to classify how advanced the disease is. Staging typically follows the Ann Arbor system used for lymphomas, which ranges from Stage I (disease in a single location) to Stage IV (widespread disease affecting multiple organs). Most people with plasmablastic lymphoma present with Stage III or IV disease, meaning the cancer is already quite extensive at diagnosis.^[3]

The International Prognostic Index (IPI) is commonly used to assess risk. This scoring system considers several factors including age, disease stage, blood levels of an enzyme called lactate dehydrogenase (LDH), performance status (how well a person can carry out daily activities), and the number of sites outside lymph nodes where the disease appears. For plasmablastic lymphoma, patients typically fall into intermediate to high-risk categories based on IPI scoring.^[5]

Required Laboratory Tests

Clinical trials typically require comprehensive blood work before enrollment. This includes a complete blood count to measure red blood cells, white blood cells, and platelets. Doctors also assess liver and kidney function through blood tests measuring enzymes and other markers. These baseline measurements help determine if someone is healthy enough to tolerate the experimental treatment and provide a comparison point for monitoring side effects during the trial.^[4]

For HIV-positive individuals, which represents a significant portion of plasmablastic lymphoma patients, trials may require documentation of HIV viral load and CD4 count. Some trials might have specific requirements regarding HIV control, such as being on stable antiretroviral therapy.^[8]

Confirmation of Diagnosis

Clinical trials typically require centralized pathology review, meaning that tissue samples must be reviewed by expert pathologists who specialize in lymphomas. This ensures that all participants truly have plasmablastic lymphoma and not a similar-appearing condition. The review process examines the same features described earlier—histology, immunophenotyping results, and genetic findings—but adds an extra layer of expert verification.^[4]

Documentation of specific molecular features may also be required. For example, some trials might specifically enroll only patients whose tumors have MYC rearrangement or are EBV-positive, while others might exclude these patients. Knowing the MYC status and EBV status of the tumor is therefore essential for matching patients to appropriate clinical trials.^[5]

Imaging Requirements

Most clinical trials require baseline imaging studies to document the extent and location of disease. This typically includes CT scans of the chest, abdomen, and pelvis. Some trials may also require PET-CT scans, which combine anatomical imaging with metabolic imaging to show areas where cancer cells are actively growing. These baseline scans are crucial because they provide a reference point for measuring whether the experimental treatment is working during the trial.^[10]

Performance Status Assessment

Performance status measures how well a person can carry out daily activities and care for themselves. Clinical trials typically use standardized scales such as the ECOG (Eastern Cooperative Oncology Group) performance status or Karnofsky performance scale. These assessments help determine if someone is physically strong enough to participate in a trial. Many trials exclude people with poor performance status because they may not tolerate intensive treatments well.^[8]

Additional Assessments

Depending on the specific trial, additional specialized tests may be required. For instance, if the experimental treatment targets a specific protein on cancer cells, such as CD38, the trial might require confirmation that tumor cells express that protein. Cardiac function tests, such as an echocardiogram or MUGA scan, might be needed for trials using drugs that can affect the heart. Neurological assessments might be required for treatments that could impact the nervous system.^[8]

Some trials examining the role of the immune system in controlling cancer may also require specialized immune function tests or analysis of tumor-infiltrating immune cells. These more specialized assessments help researchers understand not just whether a treatment works, but why it works or doesn’t work in particular patients.

Prognosis and Survival Rate

Prognosis

The prognosis for plasmablastic lymphoma remains challenging despite advances in treatment. This is an aggressive disease with a tendency to relapse even after intensive chemotherapy. Several factors influence how the disease might progress and what outcomes a patient might expect. Performance status—meaning how well a person can function in daily activities—plays an important role. People who are able to maintain good physical function generally have better outcomes than those who are significantly limited in their activities.^[8]

Achieving complete remission after the first round of treatment is one of the most important factors affecting prognosis. Patients who reach complete remission have significantly better outcomes than those who do not respond fully to initial therapy. The clinical stage at diagnosis also matters; however, most people with plasmablastic lymphoma present with advanced stage III or IV disease, which makes treatment more challenging.^[8]

The status of the MYC gene and the International Prognostic Index (IPI) score also influence outcomes. Additionally, the presence of Epstein-Barr virus in tumor cells has been identified as an independent factor affecting overall survival in some studies. Interestingly, there appear to be differences in prognosis between HIV-positive and HIV-negative patients, with some studies suggesting different clinical patterns and outcomes between these groups.^[10]

One variant of the disease, sometimes called plasmablastic lymphoma of the elderly, appears to have a significantly better prognosis than most other cases. This variant seems related to age-related immune system changes rather than severe immune suppression from HIV or transplants.^[3]

Survival Rate

Survival rates for plasmablastic lymphoma vary considerably across different studies and patient populations. Recent reports indicate that median progression-free survival—the length of time during and after treatment that the cancer does not grow or spread—ranges between 6 and 11 months. This relatively short timeframe reflects the aggressive nature of the disease and its tendency to return after treatment.^[8]

Overall survival rates have shown some improvement in recent years. The most recent studies report median overall survival ranging from 14 to 57 months. This wide range reflects differences in patient populations, treatment approaches, and other factors. The improvement compared to older studies suggests that advances in both lymphoma treatment and HIV management (for HIV-positive patients) may be helping some people live longer with this disease.^[8]

Patients with limited-stage disease, meaning the cancer is confined to one or a few nearby areas, tend to have better survival outcomes than those with widespread disease. Pediatric cases, though rare, have also shown better long-term survival rates in some reports. Some individuals with early-stage disease have achieved long-term complete remission, though this remains uncommon.^[8]

It’s important to understand that these are statistical averages, and individual outcomes can vary significantly. Factors such as response to treatment, overall health, age, immune system status, and access to specialized care all play roles in determining an individual’s prognosis. Additionally, ongoing research and clinical trials continue to explore new treatment approaches that may improve survival rates in the future.^[4]

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