Hepatosplenic T-cell lymphoma

"Hepatosplenic" means liver and spleen, and that is where this lymphoma lives — in the liver, the spleen and the bone marrow, rather than in the lymph nodes where people expect to find a lymphoma.

Most cases arise from gamma-delta T cells, an uncommon subset of T cell that normally patrols tissue surfaces rather than circulating through the lymph nodes. That origin is part of why the disease sits where it does.

It is extremely rare. Fewer than 100 cases had been described in the entire world literature between the condition first being defined in 1990 and a 2009 review.

It typically affects younger adults — the median age in one 15-person series was 38, and Lymphoma Action describes it as typically arising in people in their mid-thirties — and it is more common in men.

The cause is not established.

There is a recognised association with long-term suppression of the immune system. Lymphoma Action names immunosuppression after an organ transplant, and treatment for Crohn’s disease.

The clearest published statement of that association is in the safety labelling for one class of drug. The boxed warning on infliximab reports cases occurring after the drug was on the market, notes that almost all of those people were also taking a thiopurine — azathioprine or 6-mercaptopurine — and that the majority occurred in adolescent and young adult males with Crohn’s disease or ulcerative colitis.

That is a reported pattern, not a measured risk. The warning reports cases; it does not give an absolute rate. In the 15-person series, 4 people had a history of a suppressed immune system, and the authors cite a literature estimate that roughly 10% to 20% of people with this lymphoma had prior immune suppression. Those denominators are far too small to build a rate on.

If you have been diagnosed with this while on long-term treatment for inflammatory bowel disease, the honest position is that an association is recognised and carries a formal warning, that the absolute risk is extremely small, and that any decision about your bowel disease treatment belongs to you and your gastroenterologist. Nothing on this page is a reason to stop taking anything.

The presentation is distinctive, and it is not what people expect from a lymphoma. In the 15-person series, every single person had an enlarged spleen and bone marrow involvement, two thirds had liver involvement, and only two had swollen lymph nodes.

Most had anemia and low platelets, and most had what are called B symptoms — fever, night sweats and weight loss.

So the presenting problems are an enlarged spleen and liver, tiredness and breathlessness from anemia, and bruising or bleeding from low platelets, in someone who has none of the lumps they would have gone looking for.

It is aggressive, and the published outcomes are poor. In that series the median overall survival was 11 months, and complete remissions achieved with chemotherapy alone were typically short — a median of 8 months.

Those numbers come from 15 people at a single centre, described in 2009. They are the best evidence available and they are also very thin evidence, and both of those things are worth knowing.

There is no established standard regimen. Response to the usual lymphoma chemotherapy protocols is poor, and remissions are usually short.

That is the reason a transplant enters the picture early here rather than after a relapse, which is unusual among the lymphomas.

Lymphoma Action states only that a stem cell transplant might give a better chance of staying in remission. It does not specify which kind, and we are not going to fill that gap by guessing.

Because the disease is so rare, treatment is usually at a specialist centre and often within a clinical trial.

It is usually diagnosed in a young adult, often without the swollen lymph nodes people associate with lymphoma — which means the route to the diagnosis frequently runs through an unexplained enlarged spleen, anemia or low platelets.

For someone diagnosed while being treated for Crohn’s disease or ulcerative colitis, there is a specific and painful question about whether their medication was involved. It deserves a real answer from their own team rather than a search result.

It is rare enough that most people will be the only case their local team has seen, and rare enough that there is very little written for patients rather than for clinicians.

The published outcomes are hard, and we have not softened them. They also rest on a very small number of people treated more than fifteen years ago.

This is one of the conditions where a donor transplant is part of first-line thinking rather than something that comes after a relapse.

EBMT’s 2025 recommendations state in their narrative text that a donor transplant is strongly recommended in first-line therapy for this disease, along with two other rare T-cell lymphomas. They add that while people transplanted in remission do better, those whose disease is stable or progressing should still be considered — because the other treatments do not usually produce long-term remission.

The evidence behind that is genuinely small. In the 15-person series, three people had a transplant: one using their own cells and two using a donor’s. All three were alive and in complete remission when the report was written. Three people cannot support a percentage or a general claim, and we are giving you the count rather than dressing it up.

Where a donor transplant is the right route and no relative matches, that donor comes from a registry. That is a real reason someone might join one.