Histological Features
Histologically, WM is characterized by the presence of small lymphocytes, plasmacytoid lymphocytes, and
plasma cells in the bone marrow. These cells often have a
perinuclear hof and abundant basophilic cytoplasm. The bone marrow biopsy typically shows an interstitial infiltrate of these cells, occasionally forming nodular aggregates. Reticulin fibrosis may also be observed.
Diagnostic Markers
Several immunohistochemical markers are used to diagnose WM. The malignant cells typically express
CD19,
CD20, and
CD22, which are B cell markers. They may also express CD138, a marker for plasma cells. The detection of monoclonal IgM paraprotein in the serum is a key diagnostic criterion.
Role of Bone Marrow Biopsy
A bone marrow biopsy is crucial for the diagnosis of WM. It helps in identifying the characteristic infiltration pattern and the morphology of the malignant cells. The biopsy also aids in ruling out other disorders that may present similarly, such as multiple myeloma and other lymphomas.Clinical Implications
The overproduction of IgM can lead to hyperviscosity syndrome, causing symptoms such as visual disturbances, headaches, and bleeding. The infiltration of the bone marrow by malignant cells can result in anemia, thrombocytopenia, and neutropenia. Additionally, patients may present with enlarged lymph nodes and spleen.Treatment Considerations
While there is no cure for WM, treatment options aim to manage symptoms and reduce the burden of the disease. Therapeutic approaches include the use of
rituximab, a monoclonal antibody targeting CD20, and chemotherapeutic agents such as
bendamustine and
proteasome inhibitors. Plasmapheresis may be used to manage hyperviscosity symptoms.
Prognosis and Follow-up
The prognosis of WM varies, with median survival times ranging from several years to over a decade, depending on various factors such as age, overall health, and response to treatment. Regular follow-up with blood tests and imaging studies are essential for monitoring disease progression and treatment efficacy.
