Reading T-cell lymphoma reports: connecting pathology, PET scans and blood results

A pathology report may say CD30 positive, a marrow report may find no definite lymphoma, and a PET report may describe several active sites. These statements can coexist. Each test examines different material and answers a different question. The useful task is to identify what has been established, what remains uncertain, and which result would change a treatment decision. Counting positive markers or abnormal arrows cannot provide an overall severity score.

Key takeaways

These excerpts come from the original article. Read the full sections below for context.

Before reading the unfamiliar abbreviations, check where the sample came from, when it was taken and whether it was collected before treatment. A removed lymph node, a small skin sample and a marrow core are not interchangeable pieces of evidence. Differences between them may reflect the sampled location, the amount of abnormal tissue, treatment effects or an actual change in disease.
EBER in situ hybridisation evaluates a viral signal in tissue. Blood EBV DNA measurement is a different test. Although both refer to EBV, one result cannot simply substitute for the other. Viral evidence has a particular role in some T-cell and NK-cell entities, but an isolated raised blood measurement cannot assign a lymphoma subtype without the required clinicopathological evidence. Trends also need the treatment stage and concurrent clinical events. d’Amore et al.: ESMO–EHA guideline for peripheral T- and NK-cell lymphomas, 2025
It is reasonable to ask the clinician to write the current complete diagnosis, the assessed response and the finding that determines the next step. Any unresolved issue should remain visibly unresolved in the record. A later addendum can update it. Forcing every ambiguous word into either reassuring or frightening news creates certainty that the evidence does not provide.

Quick answer

Full guide

Start with the specimen and the status of the conclusion

Before reading the unfamiliar abbreviations, check where the sample came from, when it was taken and whether it was collected before treatment. A removed lymph node, a small skin sample and a marrow core are not interchangeable pieces of evidence. Differences between them may reflect the sampled location, the amount of abnormal tissue, treatment effects or an actual change in disease.

Also look for an addendum. A preliminary report may have been issued before additional stains, molecular results or specialist review became available. Phrases such as “consistent with,” “favoured” and “cannot exclude” do not express the same degree of certainty. Ask which integrated diagnosis is currently being used and keep both the original report and its updates. The CAP lymphoma workup guideline explains why sample adequacy and the choice of ancillary tests need to match the diagnostic question. A provisional label on inadequate tissue is not necessarily a completed classification. CAP/ASCP: Laboratory Workup of Lymphoma in Adults guideline

For an appointment, make a short note of the accepted diagnosis, the unresolved findings and whether any of those findings must be clarified before the next treatment. This is more useful than ordering another broad panel whenever an unfamiliar term appears. If urgent treatment has already started, ask how that timing affects interpretation of later samples.

Read the complete disease name

The phrase T-cell lymphoma covers illnesses with substantially different treatment pathways. Mature systemic T-cell disease, a primary cutaneous lymphoma and T-lymphoblastic lymphoma should not lose their distinguishing words in a referral. Within mature disease, systemic anaplastic large cell lymphoma, a nodal follicular helper T-cell lymphoma and peripheral T-cell lymphoma not otherwise specified are also separate entities. Classification integrates morphology, immunophenotype, molecular findings and the clinical setting. Campo et al.: International Consensus Classification of Mature Lymphoid Neoplasms, 2022

An older report may use angioimmunoblastic T-cell lymphoma while a later report places the same illness within a nodal follicular helper T-cell category. The team should explain whether this is a change in terminology, a more precise classification or a genuinely revised diagnosis. The word “follicular” does not make this a follicular B-cell lymphoma. A translated report should retain the full entity name rather than shortening everything to the general heading.

CD30, ALK and Ki-67 should not be read as interchangeable scores

CD30 interpretation includes which cells stain and the pattern and extent of expression. It can contribute to classification and to discussion of a CD30-directed treatment, but CD30 positivity alone does not establish systemic anaplastic large cell lymphoma. ALK results likewise need the accompanying morphology and clinical information. A negative stain means that the test did not demonstrate that particular finding; it does not mean there is no cancer. d’Amore et al.: ESMO–EHA guideline for peripheral T- and NK-cell lymphomas, 2025

Ki-67 describes proliferative activity in the sampled tissue. It is not a stopwatch for tumour doubling and cannot be converted into a personal life expectancy. Comparing two percentages requires attention to the specimens, methods, sampled regions and intervening treatment. If the difference is considered clinically meaningful, ask the pathologist or treating clinician to explain why rather than applying a threshold from an unrelated lymphoma website.

A biomarker also does not function as an automatic prescription. Treatment eligibility still depends on the precise disease, prior therapy, fitness, evidence and the relevant drug label. NCI's biomarker guidance explains that finding a potentially relevant alteration does not guarantee benefit from a matching treatment. For a consultation in China, provide the underlying test and ask how the proposed use is supported locally; a translated phrase such as “target positive” is insufficient. NCI: Biomarker Testing for Cancer Treatment

Establish what a molecular test actually sampled

Molecular reports may list a variant frequency, evidence tier, assay sensitivity and technical limitations. First establish whether testing used tumour tissue, marrow or peripheral blood. Then ask whether the purpose was classification, treatment selection, monitoring or investigation of inherited susceptibility. A mutation detected in blood can sometimes arise from an accompanying blood-cell clone rather than uniquely identifying the lymphoma cells. A single result should not overturn the whole tissue assessment without a coherent explanation. Campo et al.: International Consensus Classification of Mature Lymphoid Neoplasms, 2022

Clonal T-cell receptor findings also require context. Non-malignant clonal expansions occur, while low tumour content and technical factors can limit detection. The CAP guideline therefore does not support indiscriminate upfront clonality testing in every suspected case. A positive result should be reconciled with morphology and the abnormal cell population; a negative result should be interpreted alongside the remaining evidence. Neither word resolves every diagnostic uncertainty on its own. CAP/ASCP: Laboratory Workup of Lymphoma in Adults guideline

A variant of uncertain significance has insufficient established clinical meaning for a confident application. It is not a reason to purchase an experimental product or ask all relatives to undergo testing. If inherited risk is suspected, specialists can advise on appropriate material and counselling. Testing a tumour for acquired changes and testing a person for a germline condition are different exercises. The report should make clear which was performed. NCI: Biomarker Testing for Cancer Treatment

Keep EBV and HTLV-1 findings in their proper setting

EBER in situ hybridisation evaluates a viral signal in tissue. Blood EBV DNA measurement is a different test. Although both refer to EBV, one result cannot simply substitute for the other. Viral evidence has a particular role in some T-cell and NK-cell entities, but an isolated raised blood measurement cannot assign a lymphoma subtype without the required clinicopathological evidence. Trends also need the treatment stage and concurrent clinical events. d’Amore et al.: ESMO–EHA guideline for peripheral T- and NK-cell lymphomas, 2025

Adult T-cell leukaemia/lymphoma is associated with HTLV-1 and should not be confused with every T-cell lymphoma occurring in an adult. WHO distinguishes HTLV-1 infection from the illnesses associated with it; infection does not mean that everyone develops this cancer. If screening or confirmatory tests appear in the record, ask whether infection has been established and whether the tissue and blood findings support the particular disease. A positive screening test is not the entire classification. WHO: Human T-lymphotropic virus-1, December 2025

This distinction matters when seeking another opinion abroad. A short referral saying “virus positive T-cell cancer” removes information the receiving team needs. Send the actual assay name, specimen, result, units where relevant and the accompanying interpretation. Preserve a negative or indeterminate confirmatory result as carefully as a positive screen.

A PET hot spot needs a comparison and an explanation

SUV measures tracer uptake under the conditions of the examination; it does not count lymphoma cells. Infection, inflammation and tissue recovery can complicate interpretation. Lymphoma assessment compares the location and metabolic behaviour of lesions with the baseline study and uses defined response methods, including the Deauville framework when applicable. Focusing only on the largest SUV misses that broader assessment. Cheson et al.: Lugano classification for lymphoma evaluation and response

A shrinking mass may remain visible after successful therapy. Conversely, size alone cannot establish whether a persistent lesion is active. The PRoLoG consensus addresses integration of metabolic and anatomical findings and the handling of uncertainty. When one new focus would lead to a major change, such as changing systemic therapy or reconsidering transplantation, ask what evidence supports that conclusion and whether review, interval assessment or tissue confirmation is appropriate. That does not mean every abnormal focus requires a biopsy. PRoLoG Consensus Initiative: clinical application of Lugano assessment

“Complete metabolic response” describes the response criteria met at an assessment point. It cannot rule out every future relapse. “Partial response” must also be read with its timing: a scan during treatment does not necessarily carry the same implication as an end-of-treatment scan. Supply dates of treatment and relevant recent infections or medicines to the imaging team rather than asking them to interpret an isolated image without context.

Understand why marrow and PET findings can disagree

A marrow biopsy samples a limited area, whereas PET provides information across the body. The CHEMO-T PET substudy in PTCL documented imperfect agreement between the tests, including biopsy-positive cases with PET-negative marrow and findings in the opposite direction. These observations support an integrated assessment rather than a claim that either test is universally decisive. CHEMO-T investigators: PET/CT substudy in peripheral T-cell lymphoma, 2025

If a discrepancy changes staging, ask how the final clinical stage was assigned and whether another explanation for the abnormality is plausible. Marrow reports can also describe treatment effects or other changes in blood production. Not every abnormal phrase means infiltration by lymphoma. Keep morphology, biopsy, flow cytometry and molecular pages together when transferring care; a one-line summary of “marrow negative” can omit relevant detail.

Read laboratory arrows as dated measurements

LDH can contribute to risk assessment but is not specific to T-cell lymphoma. Blood counts and liver tests can change for several reasons, including therapy, infection and other health problems. NCI's discussion of tumour markers explains why a measurement usually needs other evidence: an isolated abnormal result does not establish relapse, and a normal result does not replace follow-up. NCI: Tumor Markers

Record the actual result, unit, reference range and date instead of only the words high or low. This is especially useful when laboratories in different countries use different methods or units. If treatment is postponed because of a result, ask whether the concern is infection, bleeding, organ toxicity or a need to reassess disease. Obtain a plan for repeat testing and an appropriate contact route.

Reporting a new fever, substantial breathlessness, confusion or persistent bleeding should not wait until the entire record has been translated. The immediate clinical problem takes priority over arranging an ideal document set. A photograph or electronic copy of available results can accompany urgent care while the remaining paperwork is collected.

Leave the consultation with an interpretation you can use

It is reasonable to ask the clinician to write the current complete diagnosis, the assessed response and the finding that determines the next step. Any unresolved issue should remain visibly unresolved in the record. A later addendum can update it. Forcing every ambiguous word into either reassuring or frightening news creates certainty that the evidence does not provide.

When requesting another opinion, organise reports by date and mark whether each sample or scan was before treatment, during treatment or after completion. Include the treatment list on the same timeline. This allows the next team to assess what changed and why, rather than comparing disconnected numbers. The resulting conversation can focus on a concrete decision: whether the diagnosis is sufficiently secure, whether the response needs further clarification, or whether the current plan should continue.