Page 400 - Textbook of Pathology, 6th Edition

384 Treatment and Prognosis 1. Hyperviscosity syndrome is the major clinical manifestation.
It results in visual disturbances, weakness, fatiguability,
Treatment of multiple myeloma consists of systemic
chemotherapy in the form of alkylating agents and weight loss and nervous system symptoms. Raynaud’s
symptomatic supportive care. Autologous stem cell phenomenon may occur.
transplantation and interferon-therapy are the other modern 2. Moderate organomegaly in the form of lymphadenopathy,
treatment modalities offered. Poor prognostic predictors for hepatomegaly and splenomegaly are frequently seen.
lower survival are: secretion of λ-light chain than those 3. Anaemia due to bone marrow failure may be present.
secreting κ-light chain, larger number of cytogenetic 4. Bleeding tendencies may occur due to interaction of
abnormalities, and increased β-2 microglobulin level. The macroglobulins with platelets and coagulation factors.
median survival is 2 years after the diagnosis is made. The DIAGNOSIS. Unlike myeloma, there are no characteristic
terminal phase is marked by the development of radiologic findings. The diagnosis rests on laboratory data
pancytopenia, severe anaemia and sepsis. as under:
1. Pleomorphic bone marrow infiltration
LOCALISED PLASMACYTOMA
2. Raised total serum protein concentration
Two variants of myeloma which do not fulfil the criteria of 3. Raised serum monoclonal M component which is due to
classical triad are the localised from of solitary bone IgM paraprotein
plasmacytoma and extramedullary plasmacytoma. Both these are 4. Elevated ESR
associated with M component in about a third of cases and 5. Normocytic normochromic anaemia.
occur in young individuals. Solitary bone plasmacytoma is The management of the patients is similar to that of
SECTION II
a lytic bony lesion without marrow plasmacytosis. myeloma. Patients respond to chemotherapy with a median
Extramedullary plasmacytoma involves most commonly the survival of 3-5 years.
submucosal lymphoid tissue of nasopharynx or paranasal
sinuses. Both variants have better prognosis than the classic HEAVY CHAIN DISEASES
multiple myeloma. Plasma cell granuloma, on the other hand,
is an inflammatory condition having admixture of other Heavy chain diseases are rare malignant proliferations of B-
inflammatory cells with mature plasma cells, which can be cells accompanied by monoclonal excess of one of the heavy
easily distinguished by a discernible observer. chains. Depending upon the type of excessive heavy chain,
three types—γ, α and μ, of heavy chain diseases are
WALDENSTRÖM’S MACROGLOBULINAEMIA distinguished:
GAMMA HEAVY CHAIN DISEASE. Also called Franklin’s
Waldenström’s macroglobulinaemia is an uncommon
1
malignant proliferation of monoclonal B lymphocytes which disease, it is characterised by excess of mostly γ -paraprotein,
secrete IgM paraproteins called macroglobulins as they have both in the serum and urine and is demonstrated as M
high molecular weight. The condition is more common in component. Clinically, the condition may develop at any age
men over 50 years of age and behaves clinically like a slowly and present with lymphadenopathy, splenomegaly,
progressive lymphoma. hepatomegaly, involvement of pharyngeal lymphoid tissue
The exact etiology is not known but a possible relation- (Waldeyer’s ring) and fever. Patients have rapidly downhill
ship of IgM macroglobulin with myelin-associated course due to severe and fatal infection.
glycoprotein which is lost in degenerating diseases has been ALPHA HEAVY CHAIN DISEASE. This is the commonest
suggested. The clinical evidence in favour is the appearance of heavy chain diseases characterised by α-heavy chains in
of peripheral neuropathy before the occurrence of macro- the plasma which are difficult to demonstrate in electropho-
globulinaemia in some patients. resis due to rapid polymerisation. The patients present with
Haematology and Lymphoreticular Tissues
bowel symptoms such as chronic diarrhoea, malabsorption
MORPHOLOGIC FEATURES. Pathologically, the disease and weight loss and may have enlargement of abdominal
can be regarded as the hybrid between myeloma and small lymph nodes. Chemotherapy may induce long-term
lymphocytic lymphoma. remissions.
Like myeloma, the disease involves the bone marrow,
but unlike myeloma it usually does not cause extensive MU HEAVY CHAIN DISEASE. This is the rarest heavy
bony lesions or hypercalcaemia. The bone marrow shows chain disease. The neoplastic B-cells produce μ heavy chains
pleomorphic infiltration by lymphocytes, plasma cells, which donot appear in the urine but κ light chains which are
lymphocytoid plasma cells, mast cells and histiocytes. Like also produced appear in the urine. Another feature that
in myeloma, serum M component is present. distinguishes this type of heavy chain disease from the others
is the presence of vacuoles in the malignant B lymphocytes.
Unlike myeloma and more like small lymphocytic
lymphoma, enlargement of lymph nodes, spleen and liver The course and prognosis are like those of leukaemia or
due to infiltration by similar type of cells is present more lymphoma.
frequently.
MONOCLONAL GAMMOPATHY OF UNDETERMINED
CLINICAL FEATURES. The clinical features of the disease SIGNIFICANCE (MGUS)
are due to both infiltration by the disease and paraproteins A relatively recently desribed entity, monoclonal gammo-
in the blood. pathy of undetermined significance (MGUS), is increasingly