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The lymph nodes are a major site for
metastasis of tumour by lymphatic spread. This is most
commonly seen with carcinomas and melanomas, occurring less frequently with
Clinically, development of enlarged lymph nodes may be the presenting sign of
the diagnosis being made only after histological examination of a lymph node
Tumour cells are first seen in the subcapsular sinus; they later form solid
the nodal structure. With time, tumour extends outside the nodal capsule,
nodes to adjacent structures.
Typically, nodes involved by metastatic tumour are very hard and, in advanced
cases, are fixed to other structures.
The malignant lymphomas are primary neoplastic diseases of lymphoid cells, which
divided into two main groups on the basis of clinical and pathological features.
Hodgkin's disease is characterized by neoplastic proliferation of an atypical
form of lymphoid cell eponymously termed the 'Reed-Sternberg cell'.
This is the most common type of lymphoma.
Non-Hodgkin's lymphomas are characterized by neoplastic proliferation of
T-lymphocytes or, rarely, histiocytic cells.
Hodgkin's disease involves proliferation of an atypical form of lymphoid cell
until recently, was extremely difficult to categorize - the Reed-Sternberg cell.
Clinically disease presents as enlargement of a single lymph node or group of
or enlarged nodes may be discovered following investigation for non-specific
symptoms such as weight loss, fever, or pruritus.
Affected nodes are enlarged and replaced by firm, rubbery, pinkish white tissue
The natural history of untreated disease is spread to adjacent
lymph node groups, with involvement of spleen, liver, and bone marrow.
These lymph nodes are enlarged and replaced by firm, creamy white tissue.
this example was taken from a case of Hodgkin's disease, nodes in non-Hodgkin's
lymphomas may appear identical.
Prognosis in Hodgkin’s disease is related to stage and sub-type
Histologically, four main types of Hodgkin's disease have been defined
(Rye classification), each with a different natural history and prognosis.
Common to all types of Hodgkin's disease is the presence of Reed-Sternberg
the morphology of which varies in different sub-types of disease. The difference
the types is in the extent and vigour of the host immune response associated
The response is marked in lymphocyte-predominant disease, moderate in mixed
variable in nodular sclerosis, and in lymphocyte-depleted it is virtually
The degree of associated immune response is related to prognosis, the best
seen in lymphocyte-predominant and the worst in lymphocyte-depleted disease.
Lymphocyte-predominant disease is mainly seen in young adult males.
Histologically the nodes are replaced by reactive lymphoid cells, among which
a small population of Reed-Sternberg cells of the lymphocytic/histiocytic type.
present with Stage I or II disease.
Mixed cellularity disease mainly affects adults in later life, but any
age can be affected. Lymph nodes are replaced by an infiltrate of Reed-Sternberg
the classic and mononuclear types, with a cellular response composed of lymphoid
eosinophils, plasma cells and histiocytes.
Over 50% of patients present in Stage III or IV.
Lymphocyte-depleted disease is mainly seen in elderly adults. The infiltrate
is composed of many pleomorphic Reed-Sternberg cells, and shows few reactive
Most patients with this pattern present with Stage III or IV disease; it is
with the poorest prognosis.
Nodular sclerosis is the most common type of Hodgkin's disease, mainly affecting
young adults. In most cases the mediastinal nodes are involved at presentation.
The key feature is that the infiltrate is divided into nodules by broad bands of
In nodular sclerosis Type I the infiltrate is cytologically the same as in mixed
cellularity disease. In nodular sclerosis Type II the infiltrate contains
Reed-Sternberg cells and there is lymphocyte depletion.
Non-Hodgkin's lymphomas may be classified as nodal (tumours originating in
lymph nodes, which account for the vast majority of cases) or extranodal
(tumours originating in specialized groups of lymphoid cells). Most extranodal
lymphomas arise in specialized epithelial-associated lymphoid cells
(mucosa-associated lymphoid tissue - MALT), and cases are seen in the gut and
Other examples develop in tissues that have been the seat of chronic lymphocytic
inflammation in organs not normally noted to have a lymphoid population
(e.g. testis and thyroid). Lymphomas may also develop in the brain and skin as a
Non-Hodgkin's lymphomas can be derived from either B- or T-lymphocytes.
They are composed of a predominant cell type, which can be identified
with one of the stages of differentiation of normal T- or B-cells.
On the basis of their cytology, phenotype and clinical behaviour, non-Hodgkin's
lymphomas have been divided into four main groups:
1 Low-grade B-cell lymphomas (50% of cases).
2 High-grade B-cell lymphomas (30% of cases).
3 Low-grade T-cell lymphomas (10% of cases).
4 High-grade T-cell lymphomas (10% of cases).
In older classifications, histiocytic lymphomas were included.
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