Lymphatics Flashcards
The lymphoid system includes the cellular systems and organs involved in an immune response, made up of the?
Lymph Nodes
Spleen
Thymus Gland
Most common disorders of the lymphatics are a result of?
Reactive proliferations seen in the lymph nodes & spleen (due to an abnormal immune response)
Primary tumors (collectively called lymphomas)
Neoplastic Disease – Leukemia’s
Diseases which cause splenomegaly or a mass in the thymus gland.
What is the lymphatic system?
Lymphatic system is a series of vessels, organs & tissues which work to move a colorless watery fluid called lymph back into the bloodstream.
What is lymphoedema?
Swelling due to blocked lymph drainage
can be either:
Primary
Inherited abnormality
Secondary
Post surgery (.e.g breast cancer)
Post infection (e.g. filariasis, a tropical parasitic disease).
What is the main function of lymph nodes?
is to allow the interaction of antigens, antigen presenting cells and lymphoid cells to produce an immune response.
Different types of stimuli will produce a different response patterns in lymph nodes
which can be helpful in the identifying (diagnosing) the cause.
An enlarged lymph node it the most commonly due to reactive lymphadenopathy.
What is Lymphadenopathy?
Localised
Often indicates a local inflammatory response which is being drained away.
Palpable Lymph Nodes
Doesn’t always indicate a serious problem
could be due to minor trauma or recent infection
Can also occur in chronic inflammatory conditions
Can indicate neoplastic disease
What are the 5 main patterns of response with enlarged lymph nodes?
Follicular Hyperplasia
Paracortical Hyperplasia
Sinus Hyperplasia
Granulomatous Inflammation
Acute Lymphadenitis
Different conditions will present in different ways e.g. follicular seen in chronic inflammation such as RA, whilst granulomatous seen in TB and Chron’s
True or false? Metastatic Tumour is a common cause of lymphadenopathy
True
Lymph nodes are a major site for metastasis of tumour by lymphatic spread. True or false?
True - Lymph nodes are a major site for metastasis of tumour by lymphatic spread.
Most commonly seen in carcinoma’s and melanomas (less so sarcomas).
Clinically, an enlarged lymph node may be the only presenting sign of a tumour
with diagnosis only made after lymph node biopsy.
How does a metastatic lymph node present?
Tumor cells are first seen in the subcapsular sinus
they later form solid areas, replacing the nodal structure
With time, tumor extends outside of the nodal capsule and attaches to adjacent structures.
Typically, nodes involved in metastatic tumor are very hard and in advanced cases, are fixed to other structures.
Neoplastic Disease of White Blood Cells are divided into 4 main groups. What are they?
Malignant Lymphoma
Leukaemia’s
Plasma Cell Tumours
Histiocytosis
What are lymphoma?
Lymphomas are neoplasms derived from lymphoid cells.
The malignant lymphomas are primary neoplastic diseases of lymphoid cells which are divided into two main groups
(based on clinical & pathological features):
Hodgkin’s Lymphoma
&
Non- Hodgkin’s Lymphoma
What is Hodgkin’s lymphoma?
Caused by proliferation of an atypical form of lymphoid cell called the Reed- Sternberg Cell.
Clinically, the disease presents as:
an enlargement of a single lymph node, or group of nodes
or, discovery of enlarged nodes following investigations of non-specific symptoms such as weight loss, fever or pruritus.
Macroscopically, the affected nodes are enlarged (generally up to 2cm in diameter) and are replaced by firm, rubbery pinkish white tissue.
If not treated, the disease will spread to adjacent lymph nodes groups and can involve the spleen, liver and bone marrow.
Diagnosis
Lymph Node biopsy (and liver biopsy if suspected liver spread)
Then extent of disease is assessed by staging
CT or MRI are used to detect degree of spread & infliltration.
What 5 histological types are Hodgkin’s lymphoma divided into?
Nodular Lymphocyte – Predominant (mainly seen in young men)
Mixed cellularity (mainly adults in later life)
Nodular Sclerosis (most common type affecting young adults)
Lymphocyte rich
Lymphocyte depleted (mainly seen in elderly adults)
Common feature of all is the presence of Reed- Sternberg Cells.
What is non-Hodgkin’s lymphoma?
Originate either from B- Cells or T- Cells
Characterized by neoplastic proliferation of B-lymphocytes, T- lymphocytes & very rarely histiocytic cells.
Usually starts in the lymph nodes, and then spread to the spleen, liver & bone marrow.
Other organs can be involved in the advanced stage
Lymphoma’s are grouped according to their site of origin.
Classified as either:
Nodal
Tumors originating from the lymph nodes
Most cases
Extranodal
Tumors originating from specialized lymphoid cells.
Most arise from Mucosa- associated lymphoid tissue – MALT (a specialized epithelial associated lymphoid cell) e.g. the gut or lung
They will be made up of a predominant cell type (from when cell differentiation occurs).
Generally speaking,
Cells which small nuclei will grow slowly.
Cells with larger nuclei, will grow faster – associated with a more aggressive type of cancer.
