Lymphoplasmacytic lymphoma is an uncommon sub-type of non-Hodgkin lymphoma (NHL) occurring mainly in older people. It results from a neoplastic proliferation of post-germinal centre B cells with some degree of maturation to plasma cells . The term encompasses Waldenström’s macroglobulinaemia, which is defined in the WHO classification  as a lymphoplasmacytic lymphoma with an immunoglobulin (Ig) M component and bone marrow infiltration. Various diagnostic criteria have been proposed [2–4].
The presentation is very variable with some clinical features being typical of lymphoma (hepatomegaly, splenomegaly and lymphadenopathy) and others being the result of the paraprotein that is often present . Patients with a high concentration of an IgM paraprotein may have the clinical presentation of Waldenström’s macroglobulinaemia, specifically increased plasma volume and hyperviscosity leading to retinal abnormalities, haemorrhage, cardiac failure and cerebral or neurological symptoms. Other patients have clinical features resulting from a paraprotein that is a cold agglutinin (chronic cold haemagglutinin disease) or a cryoglobulin (either essential or type I cryoglobulinaemia or type II cryoglobulinaemia) or has antibody activity leading to peripheral neuropathy. Hepatitis C has been reported to be associated with type II cryoglobulinaemia and lymphoplasmacytic lymphoma in some geographical areas. The lymphoma may be preceded by a phase of IgM monoclonal gammopathy of unknown significance (IgM-MGUS). Transformation to high-grade lymphoma sometimes occurs.
Haematological and pathological features
There may be anaemia and the blood film often shows increased rouleaux formation; sometimes there are red cell agglutinates or cryoglobulin deposits. A paraprotein is usually present, most often IgM but sometimes IgG or IgA. Bence Jones protein may be detected in the urine. A minority of patients do not have a monoclonal band. The lymphocyte count may be normal or there may be mild lymphocytosis (Figure 7.1). Lymphocytes are small and mature and may show plasmacytoid features — abundant basophilic cytoplasm with a small Golgi zone. Larger cells may be present if transformation occurs (Figure 7.2).
Peripheral blood film from a patient with lymphoplasmacytic lymphoma showing rouleaux and one lymphoid cell with an eccentric nucleus and an ill-defined Golgi zone. Romanowsky stain, ×100 objective.
Peripheral blood film from a patient with large cell transformation of lymphoplasmacytic lymphoma, showing cells with a high nucleocytoplasmic ratio with a Golgi zone being apparent in two of the three cells. Romanowsky stain, ×100 objective.
Bone marrow infiltration is usual and is characteristically by small lymphocytes admixed with plasmacytoid lymphocytes and plasma cells. Crystals or other Ig inclusions are sometimes present within lymphocytes, the term Russell body being used to indicate a rounded cytoplasmic inclusion and Dutcher body to indicate ...