Mantle cell lymphoma is a less common form of non-Hodgkin's lymphoma; it makes up about 5% of this group. It is characterised by small cells and a specific genetic translocation - CCND1 (cyclin D1).
Mantle cell lymphoma occurs more commonly in men (2:1) and is diagnosed in older populations; the median age of diagnosis is around 60.
The most commonly identified genetic change is a translocation of chromosomes 11 and 14; this usually involves immunoglobulin genes (chromosome 14) and CCND1 (chromosome 11). The cause of the translocation has not been identified.
Most malignancies are sited in lymph nodes; the spleen, liver and bone marrow are commonly involved at diagnosis. Median survival is 3 - 5 years.
Patients usually present with symptoms of fever, weight loss, sweats, or painless lymph node masses. Splenomegaly, hepatomegaly and lymphadenopathy may be palpable. CT and PET are useful for staging. Diagnosis can be confirmed by lymph node biopsy, bone marrow aspiration or analysis of peripheral blood film.
The cell population is uniform and small to medium in size. The architecture varies; follicular, diffuse and nodular patterns are described. A common feature is irregular nuclear borders; nucleoli are difficult to visualise.
Most neoplastic cells are positive for CD5, FMC-7 and CD43. CD10 and BCL6 are negative. Cyclin D1 is almost always positive.
As mentioned above, the most common findings is a translocation of chromosomes 11 and 14, leading to cyclin D1 linked to the promotor region for an immunoglobulin. Cyclin D1 is overexpressed and unregulated, leading to cell cycle progression despite actions of RB1 and other cell cycle arresting genes. Many other genetic defects are identified but are not present with the frequency of cyclin D1 translocations. A few rare cases of without t(11;14) and normal cyclin D1 levels often have translocations involving the CCND2 or CCND3 genes.
The Ann Arbor staging system is currently used for lymphoma.
|I||Involvement of one lymph node site|
|IE||Involvement of a single extra-lymphatic site|
|II||Involvement of two or more lymph node sites, on one side of the diaphragm|
|IIE||Involvement of a single extra-lymphatic site and one or more lymph node groups, on one side of the diaphragm|
|III||Involvement of lymph nodes on both sides of the diaphragm|
|IIIE||Involvement of a single extra-lymphatic site, with nodes on both sides of the diaphragm|
|IIIS||Involvement of the spleen with nodes on both sides of the diaphragm|
|IIIE+S||Involvement of the spleen, a single extra-lymphatic site, with nodes on both sides of the diaphragm|