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Neoplastic diseases of white blood cells are
divided into four main groups:
• Malignant lymphomas are diseases of tissue-based and nodal lymphocytes.
• Leukaemias and myeloproliferative disorders are malignant neoplasms derived
from cells of the bone
marrow. Neoplastic cells may circulate in the blood, secondarily colonizing
• Plasma cell tumours are neoplasms derived from terminally differentiated
B-cells derived from bone marrow.
• Histiocytoses are neoplasms derived from histiocytic cells, particularly
Multiple myeloma is most commonly seen after the age of 50 years. It is due to
neoplastic proliferation of a single clone of bone-marrow-derived plasma cells.
There are several main effects:
• Plasma cells grow within marrow, diffusely replacing normal homopoietic
tissue. Expansion may cause lytic
lesions and bone pain. Bone destruction may cause hypercalcaemia and
pathological fractures. Lesions are
most common in the vertebrae, ribs, skull, and pelvis.
• Cells synthesize monoclonal immunoglobulin chains, which accumulate in the
blood and may be detected by
serum electrophoresis as a monoclonal band. In most cases the monoclonal
immunoglobulin is IgG. When the
immunoglobulin is IgM, patients may develop
hyperviscosity of blood.
• Free light chains from excess monoclonal immunoglobulin
may be filtered by the glomerulus to enter the urine, where they can be detected
as Bence-Jones protein.
• Increased protein concentration in the blood is responsible for an elevated
ESR as a result of rouleaux
• Patients develop immune paresis and are susceptible to infection.
• In some cases the light chains form amyloid which is deposited in tissues,
particularly the renal glomeruli and heart.
• Renal dysfunction is common as a result of light-chain protein casts, with
secondary damage to tubules and
Diagnosis is based on examination of bone marrow aspirates, which show an excess
plasma cells. It is supported by finding a monoclonal immunoglobulin band on
serum protein electrophoresis,
and Bence-Jones protein in urine.
Plasmacytomas are also composed of neoplastic plasma cells and may be associated
with secretion of monoclonal immunoglobulin.
In contrast to multiple myeloma, they are solitary circumscribed lesions. In
may form osteolytic lesions. They may also develop in soft tissue. Many cases
multiple myeloma after a period of years.
Waldenstrِm's macroglobulinaemia typically affects patients over the age of 60
There is proliferation of plasmacytoid lymphoid cells in bone marrow (without
as well as in lymph nodes and spleen.
Cells secrete IgM (macroglobulin), which results in a hyperviscosity syndrome.
This lesion can
also be considered as a form of low-grade lymphoplasmacytic lymphoma.
'Benign monoclonal gammopathy' is a term applied to patients who have a
immunoglobulin band on serum electrophoresis, but have no pathologically
plasma-cell abnormality. The natural history is for many patients to develop
after a period of years.
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We give here simplified and accurate information about the disease
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