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Lymph node, Lymphomas, Non-Hodgkin lymphoma Part 3

Posted Aug. 16, 2016. Pathology

Malignant Lymphoma

The lymphomas  are monoclonal in origin.

 Definition:

 Rappaport 1996 Defined that It is neoplastic proliferation of Lymphocyte, Histiocytes and reticulum cells in lymphoid tissue in the body. It is most common in Lymph Node.

Various names:

    • These lymphomas are also called Immunoproliferative disorders.
    • Britisher calls it Reticulosis,  or Reticuloendothelial.

Lymphoma:

 This is a Misnomer because it spreads from single Lymph Node to chain of Lymph Node and distant nodes. It also spreads to liver, spleen and Bone marrow where it gives leukemia phase.

 Lymphosarcoma:

It is a special variant of NHL (PDL)

Lymphomas are classified into :

1.     Non-Hodgkin’s lymphoma

2.     Hodgkin’s lymphoma

 Confusion for classification is due to:

1.     Histogenesis.

2.     Degree of differentiation.

3.     Failure to differentiate between Lymphocyte and Epithelial cells.

4.     Difficult to differentiate  malignant or hyperplastic lesion.

Non-Hodgkin’s lymphoma (NHL)

  1. Non-Hodgkin lymphoma may be localized or generalized.
  2. 2/3 of Non-Hodgkin lymphoma are primary origin from lymph nodes  while 1/3 or extranodal and they may originate from bone marrow, Oropharynx, Gastrointestinal Tract and skin.
  3. 3% of all malignancies in western countries are non-Hodgkin lymphomas.

 Reason for classification of NHL:

    •  Categorization to know response to treatment.
    • Should be easy to be followed by pathologist.

       Well known classification of NHL are :

    •     Rappaport                               1996
    •     Bennett                                    1974
    •     Dorfman                                  1974
    •       Lukes and Collin                    1974  
    •     Lennert         
    •     Mathew                                   1976
    •     Working formulation           1982
    • Real classification (Revised European-American classification of lymphoid neoplasm) 1994

 Non-Hodgkin’s Lymphoma:

  •   Majority (80-85%) are B-Lymphocyte origin.
  •    Rest non-Hodgkin’s lymphoma are T-Lymphocyte
  •     Histiocytic in origin are uncommon.
  • Non-Hodgkin’s lymphoma 2/3 are nodal in origin including Hodgkin’s lymphoma while 1/3 are extra-nodal e.g. skin, stomach and brain.

Rappaport Classification:

Given in 1966 and modified in 1978.

Criteria of classification:

  1. This depends upon;
    1. Nodular or diffuse
    2. Cell Morphology, where we look for:
      1.  Size of cells.
      2. Nuclear shape.
      3. Nucleoli.
      4.  Cytoplasm.
      5.  Chromatin
      6.  Mitosis.
    3. Two cell subset (Lymphocytes and Histiocytes).
    4. Degree of differentiation of cells.

Classification of lymphomas by Rappaport

Nodular type   Diffuse type  
Poorly differentiated     24% well differentiated lymphocytic 5 %
Mixed cell type 12 % Poorly differentiated  16 %
Histiocytic 3 % Histiocytic  28 %
    Mixed cell type 6 %
    Lymphoblastic <5 %
    Undifferentiated (Burkitt's type)  
    Undifferentiated (Non-Burkitt's)  

       Good Points of Rappaport:

  1.  Nodular (follicular) or diffuse : This is easy to appreciate and has good prognosis.
  2. Easy to follow histologically.

Drawbacks:

  1. Type of cells are not mentioned either B or T-Lymphocyte.
  2. Transformed activated B-Lymphocytes looks like histiocytes.
  3. Small B-Lymphocyte end-stage is incorrect.

Rappaport classification is based on cytologic cell division like :

  1. Small lymphocytes.
  2. Histiocytes which are 2 to 3 times than the small lymphocytes with 2 to 5 nucleoli and abundant cytoplasm.
  3. Then are the undifferentiated cells.

 Nodular Type Non-Hodgkin's Lymphoma 

  1. These are 40% of the lymphomas.
  2. These are the tumor of old age and rear before the age of 20 years.
  3. Sex ratio is female to male is equal.
  4. These lymphomas have better prognosis.
  5. These tumors can transform into diffuse form which take at least 8 years.
  6. These tumors needs to be differentiated from follicular hyperplastic changes in the lymph node.
  7. Mitosis are rare.
  8. The cells are Follicular small cell (FSC)  and mixed cells are Small cleaved (SC) and large cleaved cells (LC)>
  9. Surface markers are :
    1. Positive surface Ig.
    2. Positive pan B CD molecule 19 +.
  10. 75% of the cases bone marrow is involved.
  11. Extranodal spread is rare.
  12. Median survival is 7 to 9 years.

Diffuse well differentiated lymphocytic lymphoma  

  1. These  are low grade and are 5% of the lymphomas.  
  2. 40% are the transform into chronic lymphocytic leukemia.                                                         
  3.  There are small B- lymphocytes with compact nuclei.
  4. The mitosis are rare.
  5. These are the tumor of old age.
  6. There is monoclonal gammopathy.
  7. Tumor marker shows surface Immunoglobulin Igm and IgD.
  8. These cells are CD19 + cells.
  9. Bone marrow is almost always positive.
  10. These are the low grade lymphomas.

Poorly differentiated Lymphoma (PDL)

  1. These can be :
    1. Nodular 
    2. Diffuse
  1. Age is middle and older age group.
  2.  These are 30% of the lymphomas.
  3. Multiple lymph nodes are involved.
  4. There may be enlargement of spleen and liver.
  5. There is infiltration of the bone marrow.
  6.  Nucleus has variable morphology.
  7. Mitosis are rare.
  8. When involve the blood and bone marrow looks like acute lymphocytic leukemia.
  9. These are also called  lymphosarcoma.

       Histiocytic Lymphoma

  1. These may be:
    1. Nodular
    2. Diffuse:
  2. These are 31% of the Rappaport lymphomas.
  3. Extranodal form is more common.
  4. Leukemic form is uncommon.
  5. Nucleus is vesicular.
  6. There are 2 to 5 nucleoli.
  7. These are large noncleaved cells.
  8. There are areas of necrosis.
  9. Prognosis is poor. 

     Mixed cell type lymphoma

  1. These are more in nodular form.
  2. In this variety histiocytes are 30 to 50%.
  3. These lymphomas may start as nodular and transform into diffuse form.

Lymphoblastic Lymphoma

  1. These are <5% of the Lymphomas.
  2. These are considered to be  T-lymphocytes.
  3. Age : These are more common in the young patients.
  4. Sex : The male to female ratio is 6 : 1.
  5. There is mediastinal mass presentation in 50 to 70% of the cases.
  6. There is early involvement of the bone marrow.
  7. Surface markers: These cells are CD 4, CD 8, CD 2, CD 5 and CD 7 positive.
  8. In these cases nucleus is lobulated.
  9. Increased number of mitosis gives starry sky appearance.
  10. These lymphomas are treated like acute lymphoblastic lymphoma.
  11. These are to be considered as high grade.

Undifferentiated Non Hodgkin's Lymphoma

Burkitt's Type

  1. This group includes Burkitt's and Non Burkitt's.
  2. This variety is more common in African countries and is endemic in form.
  3. In these patients Epstein barr virus (EBV) is positive in 98% of the cases while antibody positive in 100% of the cases.
  4. This is the disease of young children.
  5. Cell is large with size of 10 to 25 micron in diameter.
  6. There are 2 to 5 nucleoli.
  7. There are increased number of mitosis.
  8. The common site and presentation is mandible and maxilla.
  9. There is long survival in 50% of the cases.
  10. Response to treatment is good.

Non Burkitt's or American type 

  1. These are more common in the older age group and around 34 years.
  2. There is involvement of the gastrointestinal tract, ovaries and peritoneum.
  3. The cell morphology is pleomorphic.
  4. These tumors are less responsive to treatment.
  5. These are high grade lymphomas.

                                       Luke's and Collins classification lymphoma 1974

  • This classification was given on the basis of origin of the cells like B or T lymphocytes.
  • Second criteria was the cell morphology considering cells size, shape and nucleus.

Table showing various type of Lymphomas according to Lukes and Collins Classification

B - lymphocytes origin  65% T - Lymphocyte origin 20% Histiocytic origin  0.2% U - cell origin 14.8%
Small cell 9% small lymphocyte 2%        
Follicular small cleaved 28%

Convoluted lymphocyte

cut.T cell lymphoma

10%        
Follicular large cleaved 5% Lymphoma 2%        
Follicular small non-cleaved 7% Immunoblastic cells 4%        
Follicular large non-cleaved 6%            
Immunoblastic cells 3%            
Plasmacytoid cells 7%            

Drawbacks of above classification are :

  1. There is no mention of nodular type or diffuse form.
  2. This classification is difficult to follow.

                                                Working Formulation - 1982

This classification has very strong clinical significance.

 These lymphomas are divided into grades on the basis of survival of the patient.

There is consideration of B and T lymphocytes.

Following diagram  shows the differentiation of the cells when stimulated by antigenic stimulation.

 

 

Table showing Working Formulation

Low grade Intermediate grade High grade
5 years survival 50 to 70% 5 years survival 35 to 40% 5 years survival 23 to 32%
10 years survival 45% 10 years survival 26% 10 years survival 23%
Small lymphocytes B-L (SLL) Follicular predominantly large cells (LC + LNC) Large cells Immunoblastic cells (B and T cells origen)
Follicular predominantly small cleaved (SC) Diffuse small cells (SC) Lymphoblastic cells
Follicular mixed (SC + large cells) Diffuse mixed cells (SC + large cells ) Small non-cleaved (Burkitt's and non-Burkitt's)
  Diffuse large cells (LC + LNC ) Miscellaneous (Mycosis Fungoides, Sezary syndrome, Histiocytosis and HTLV-leukemia)

                                                LOw Grade Lymphomas

Small lymphocytic lymphoma (SLL)

  1. These are 4% of the lymphomas.
  2. These are well differentiated lymphocytic non-hodgkin's lymphoma.
  3. These are old age group lymphomas. 6th to 7th decadesis common.
  4. There is generalized enlargement of the lymph nodes.
  5. There is mild enlargement of liver and spleen.
  6. These lymphomas have indolent course, but difficult to eradicate owing to low proliferative index.
  7. There is no follicular pattern and these are always diffuse .
  8. These are B - Lymphocytes (95%)  with surface marker of IgM, IgD, and CD19+.
  9. While T - Lymphocytes are 5% in origen.
  10. There is compact nucleus and mitosis are rare.
  11.  40 to 60% transform into chronic lymphocytic lymphoma.
  12. Bone marrow involvement is common.
  13. Some of these lymphomas produced IgM is called Waldenstrom's Macroglobulinemia.
  14. There is prolonged survival .

Follicular Lymphoma 

 These are 40% of the adult Non-Hodgkin's lymphoma.

There are types of :

  1. Small Cleaved cell
  2. Mixed cells type consists of Small cleaved, Large cleaved and Large non-cleaved.

Follicular Small cleaved cell Lymphoma

  1. These are most common. These are 60% of the adult Non-Hodgkin's lymphoma.
  2. This more common in the middle aged and the elderly people.
  3. Nucleoli are indistinct and mitosis are rare.
  4. There are Large cleaved and Large non-cleaved cells are present but these are <20%.
  5. Median survival is 10 years.

Follicular Mixed Cell Lymphoma

  1. These are more common in the older age group (50 to 60 years).
  2. Male, female ratio is equal.
  3. There is painless enlargement of the lymph nodes.
  4. Bone marrow involvement is common, seen in 75% of the cases.
  5. These are >20% and <50% are large cells. There are large cleaved and large non-cleaved cells.
  6. Transition to diffuse form takes roughly 8 years.
  7. There are >20% and <50% of the large cells.
  8. Lymphoma cells show surface markers of Ig, and CD10, CD20 and CD21. 
  9.  Median survival is 7 to 9 years.
  10. Some believes that hands off.

                                                      Intermediate Grade  Lymphoma

 Follicular Predominantly large cells.

  1. These are uncommon lymphomas <15%.
  2. There are increased mitosis.
  3. They change into diffuse form.
  4. Prognosis is poor because they early transform into diffuse .
  5. Majority of the large cells are large cleaved and large non-cleaved.

Diffuse Small Cleaved cells lymphoma

  1. Age is around 60 years.
  2. There is increase male to female ratio.
  3. There are increased mitosis.
  4. Nucleoli are indistinct and coarse chromatin.
  5. Surface Ig and pan B- antigen (CD19 and CD20) are positive.
  6. Rarely CD10 may positive.
  7. Prognosis is poor and median survival is 3 to 4 years.

Diffuse Mixed Cell Type Lymphoma

This lymphoma consists of Small cleaved (SC), Large cleaved (LC), and large non-cleaved (LNC).

Large cleaved cells are larger than normal histiocytes or endothelial cells.

Chromatin is dispersed and nucleoli are indistinct.

Large non cleaved cells are four times the size of small lymphocytes.

Nucleoli are prominent and are 1 to 2.

Nucleus is vesicular and cytoplasm is pale.

Diffuse large cell Lymphoma

  1. This consists of large cells and Large non-cleaved cells.
  2. These are most common.
  3. There is increased male to female ration.
  4. Median age is 60 years.
  5. Extranodal signs and symptoms are more common. There is involvement of skin, gastrointestinal tract, bone and brain.
  6. There is involvement of waldeyer's ring in more than 50% of the cases.
  7. There may be diffuse masses in liver, spleen.
  8. Aggressive chemotherapy  is needed. 
  9. Remission may be seen in 60 to 80%.
  10. 50% of the patient may be symptoms free.
  11. 70% of the cases there are B- lymphocytes and 30% has T- lymphocyte.

                                                                High Grade Lymphoma

These are aggressive lymphomas. Often cured by chemotherapy.

There is high proliferative index which make more susceptible to cytotoxic drugs.
Small Noncleaved Non Hodgkin.s lymphoma are Burkitt's and Non Burkitt's lymphoma .

Large Cell Immunoblastic lymphoma

There are wide morphologic changes.

B - Immunoblastic Lymphoma:

  1. There the cells are 4 to 5 times of the small lymphocytes.
  2. There is vesicular nuclei  and 1 to 2 nucleoli.
  3. Cytoplasm is deep staining.
  4. Surface marker is CD19 and CD20 positive.
  5. 50% has history of  autoimmune diseases like Sjogren's syndrome and Hashimoto's thyroiditis and AIDs.

T - Immunoblastic lymphoma:

  1. These are seen in 5th decades.
  2. These are more common in the male.
  3. The cells have clear cytoplasm and polymorphous nuclei.
  4. These represents 20% of the childhood lymphoma.

Lymphoblastic Lymphoma:

  1. These are most common before the age of 20 years.
  2. Male : female ratio is 2 : 1.
  3. In children 40% Non Hodgkin's lymphoma falls in this group.
  4. There is early bone marrow , and meninges involvement.
  5. There may be leukemic phase looks like Acute lymphocytic leukemia.
  6. There are T - lymphocytes and looks like  T- L acute lymphocytic leukemia.
  7. Cells have uniform and scanty cytoplasm.
  8. Nucleus is lobulated and nucleoli not prominent.
  9. Increase mitosis give rise to starry sky appearance.
  10. Surface markers are CD2, Cd5, CD7 are positive. Some cells show Cd4 and CD8 positive. CD3 is positive/negative.
  11. Treatment is judt like acute lymphocytic leukemia (ALL) .  Aggressive treatment is effective.

 

 


Lymph Node, Lymphadenitis part 2

Posted July 29, 2016. Pathology

Lymphadenitis

This is the inflammation of the lymph nodes. This can be classified into the following types :

1. Acute Lymphadenitis:

  • · Specific
  • · Non-specific

2. Chronic Lymphadenitis:

  • · Specific
  • · Non-Specific

Acute Lymphadenitis (Specific). This may be :

  1. Localized e.g. Regional Lymph Node in appendicitis and tonsillitis extremities infection.
  2.  Generalized e.g In Viraemia, Bacteraemia (More common in children) 

Acute Lymphadenitis (Non-Specific)

Acute lymphadenitis may be due to the Common Organism like Staph, which leads to localized abscess. Streptococci leads to cellulites.

Other causes are Typhoid bacilli.

Acute Suppurative Lymphadenitis

sign and symptoms are :

  1. Lymph nodes are tender and hot.
  2. Microscopically there are mainly polys in the germinal centers.
  3. Pyogenic Bacteria present in the germinal center and this are may undergo necrosis.
  4. Histiocytes may contains Particulate of bacteria.
  5. Ultimately there is resolution.

 Result of acute lymphadenitis

  1. Resolution. 
  2. Abscess and draining sinuses formation.
  3. Scarring.

Chronic Lymphadenitis (Non-specific) classified into:

  1. B-Cell Hyperplasia (Follicular hyperplasia)
  2. T-Cell or Paracortical Hyperplasia
  3. Sinus Histiocytosis.

 B-Cell Hyperplasia (Hyperplastic lymphadenitis)

This is  due to infections by Microbes.

Causes of B-cell hyperplasia:

  1. Secondary Syphilis
  2. Toxoplasmosis
  3. Rheumatoid Arthritis
  4. AIDS.

Microscopic appearance of B-cell hyperplasia:

  1. Germinal centers are enlarged.
  2. Enlarged Lymph node and with presence of various stages of “Blast” transform.

D/D of B-cell hyperplasia from Follicular Lymph node:

  1. Blast cells and histiocytes  in Germinal center.
  2. There is Phagocytic activity
  3. There is presence of polys, monocytes, and eosinophils in parafollicular area.
  4. Mitosis in germinal center are seen.
  5. There is Variation in Nodule Size.
  6. Monomorphic cells in NHL.
Findings B-Hyperplasia Follicular lymphoma
Blast cells and histiocytes in germinal center present Not prominent
Phagocytic activity present not seen
Presence of polys, monocytes, eosinophils present monotonous population
Mitosis in germinal center  present usually absent
Size of nodule variable uniform

Paracortical Hyperplasia (T-cell Hyperplasia)

There is predominantly hyperplasia of T cells. The T-Cell change may encroach B-cell area.

Signs and symptoms:

  1. Skin rashes and enlarged lymph nodes.
  2. There is Fever and enlarged Liver and Spleen.
  3. Patient may have Painful Joints.

Causes:

  1. Drugs
  2. Dilantin Na
  3. S.Pox Vaccination
  4. Immunological disorder

Microscopic appearance:

  1. There is proliferation of T-Lymphocytes and  Immunoblastic cells.
  2. ay see polys, eosinophils and macrophages.
  3. Hypertrophy of sinusoids and vascular endothelial cells seen , this is  also called Pseudolymphomatous Pattern.

Sinus Histiocytosis (Sinus Hyperplasia)

  1. There is distension and prominics of Lymph sinusoids.
  2. This is  Seen in lymph node draining Carcinoma of Breast.
  3. When present in carcinoma of breast is sign of favorable prognosis.

Chronically  increased Lymph nodes are not tender and their common site is axilla and inguinal area.

Specific Chronic Lymphadenitis

May be seen in –

  1. Tuberculosis.
  2. Brucellosis.
  3. L.venereum.
  4. Sarcoidosis
  5. Histoplasmosis
Findings Tuberculosis Sarcoidosis
Granuloma soft hard
Mantoux test positive negative
Kveim test negative positive
AFB stain positive negative

Noncaseating granuloma may be seen in:

  1. Some patients with Hodgkin's disease.
  2. Crohn’s disease.
  3. Syphilis.

Immunoblastic Lymphadenitis

This condition also called Angioimmunoblastic lymphadenopathy.

It resemble clinically like Hodgkin disease and needs to differentiate histologically from it.

Signs and symptoms

  1. There may be fever.
  2. Patient may have sweating.
  3. There are skin rashes.
  4. There is generalized enlargement of the lymph nodes.
  5. There is enlarged liver and spleen.
  6. patient may history of autoimmune disease.
  7. Sometime may see autoimmune hemolytic anemia.
  8. There is polyclonal hypergammaglobulinemia.

Microscopic appearance

  1. There are small arborizing blood vessels with prominent endothelial cells.
  2. There are numerous immunoblastic cells and plasma cells.
  3. There is deposition of eosinophilic PAS positive material.
  4. There are occasional epithelial cells.

Outcome of the disease

  1. The patient may have a aplastic anemia.
  2. The patient may develop Lymphoma.
  3. Bone marrow show Lennert's lymphoma (in 70% ) of the cases.

Angiofollicular Hyperplasia 

This is also called Castleman's disease, Giant lymph node hyperplasia and Benign giant lymphoma.

Its etiology is unknown.

Signs and symptoms

  1. Usually there is presentation of mediastinal mass.
  2. There is fatigue, night sweating, nausea and weight loss. 
  3. There may be anemia and fever.
  4. there may be flu like symptoms.
  5. There is enlargement of the lymph nodes.
  6. There is hyperglobulinemia.

Microscopic appearance

There are following variant of this condition:

  1. Hyaline- vascular type
  2. Plasma cell type
  3. Mixed type 
  4. Plasmablastic type

Differential diagnosis

  • In case of mediastinal mass needs to differentiate from lymphoma.
  • From Kaposi sarcoma.

Lymphangiopathic Histiocytosis

This is also called Rosai-Dorfman disease. Also called as sinus histiocytosis with massive lymphadenopathy.

This is chronic disease and unknown etiology.

Age: This is mainly seen in children and young adults.

Signs and symptoms

  1. There is massive increase in the size of lymph nodes.
  2. There may be fever.

Microscopic appearance

  1. There is Increase in histiocytes in sinusoids.
  2. Occasional Mononuclear giant cells are seen.
  3. Follicular centers are absent.
  4. Increase plasma cells seen in the medullary cards.
  5. Capsular and Pericapsular inflammation and fibrosis are common.

Outcome

  1. This may subside.
  2. In some cases may lead to death.

Dermatopathic Lymphadenopathy

It is also called lipo melanotic Reticulosis.

This is seen in chronic inflammation or destructive (Exfoliative) lesion of the skin.

Microscope appearance:

  1. It is characterized by widened pale staining paracortical area  (T-lymphocyte Zone).
  2. There are Foamy, vacuolated macrophages.
  3. Some of the macrophage contains melanin and hemosiderin.
  4. There is Increase in Eosinophils, plasma  cells and immunoblastic cells.

Necrotizing Lymphadenitis

  1. This is Seen in:
    1. Lupus erythematosus.
    2. Bubonic Plagues.
    3. Infectious Mononucleosis.
    4. Anthrax.
    5. Typhoid.
    6. Dilantin sodium  hypersensitivity.

Microscope appearance:

  1. There is Extensive Haemorrhage.
  2. There is necrosis.
  3. This are is surrounded by the histiocytes.

Lymphadenopathy due to AIDS

Characterized by:

  1. Marked follicular hyperplasia.
  2. Infiltration of follicles by small Lymphocytes.
  3. There are  Foci of intra-follicular haemorrhage “follicle lysis”.
  4. Focal perisinusoidal or monocytoid B-cell hyperplasia.

There is High incidence of:

  1. B-cell Lymphoma.
  2. Hodgkin disease.
  3. Kaposi sarcoma.

Kikuchi Disease

  1. It is also called as Histiocytic Necrotizing Lymphadenopathy.
  2. There is unknown etiology.
  3. It is more common in young females.
  4. Histology: There is  Paracortical Necrosis surrounded by histiocytes.

Idiopathic infraction of Lymph Node

It is seen in Patient with pyrexia of unknown origin (PUO).

                                           Causes of Enlargement of Lymph Node

The causes of enlargement of the lymph node is classified as follows:

1. Localized or generalized

2. Acute:

  •  Specific
  •  Non-specific

3. Chronic:

  •  Specific
  •  Non-specific

4. Tumors:

  • Primary
  • Secondary

5. Pseudolymphomatous  conditions:

  • Follicular Hyperplasia.
  • Post vaccinal

Causes of enlargement of the lymph nodes

  1. Lymphangiopathic histiocytosis (Rosai- Dorfman disease).
  2. Angiofollicular hyperplasia (Castleman’s disease, benign giant lymphoma).
  3. Immunoblastic lymphadenopathy (Lennert’s Lymphoma).
  4. Dermatopathic Lymphadenopathy.
  5. Necrotizing lymphadenopathy.
  6. AID- lymphadenopathy.
  7. Kikuchi disease.
  8. Idiopathic infarction of Lymph Node.
  9. Cat- scratch disease.


Lymph node Structure Part 1

Posted July 27, 2016. Pathology

Lymph node 

Lymph Node are part of the reticuloendothelial system.

Reticuloendothelial SystemReticuloendothelial System is a term used by Aschoff and Kiyono with criteria of:

1.      Phagocytic activity.

2.      Staining with vital dyes.

3.      Juxtaposition to reticulum of connective tissues and lining cells of Blood vessels.

Components of Reticuloendothelial System are :

1.     Intravascular: 

  • ·       Monocytes
  • ·        Endothelial cells (Kupffer cells)
  • ·        Lymph node sinuses
  • ·        Splenic sinuses
  • ·        Adrenal Capillaries

2.      Extravascular:

  • ·        Reticulum cells
  • ·        Histiocytes and macrophages (of Connective tissues)

Lymphoid Tissue

Lymphoid tissue is present throughout the body, calculated that in a man there are about 1300g of lymphoid tissue. Lymph node contains about 100g and bone marrow about 70g.

Lymphoid tissue divided into :

Central components which includes: 

  •    Appendix
  •    Peyer's patches
  •    Thymus  
  •   Tonsils

Peripheral component includes:   

  • Lymph nodes
  • Spleen

 

 This diagram shows different parts of the Lymph node

Sinusoids are lined by the endothelial cells and in between there are flat Littoral cells.

Flat Littoral Cells has the following properties:

·        Can proliferate

·        Can Hypertrophy

·        Phagocytosis (House cleaning, functions of lymph node)

·        May detach and become free phagocytes in lymphoid  sinuses and lead to sinus histiocytosis or sinus Catarrh of German authors.

Histology:

Lymph node consists of :

  • Medulla.
  • Cortex.
  • Peripheral sinus.
  • Cortical area.
  • Deep paracortical area.
  • Sinusoides.
  • Medullary cards.
  • Afferent and efferent vessels

 

Lymph node showing detail of structure 

Primary Follicle when activated, it transform into  ---- Secondary Follicle.

Germinal center contains following cells :

  • Lymphocytes.
  • Lymphoblasts.
  • Histiocytes.
  • Mitosis.

                                                        T- Lymphocytes 

T-Lymphocytes converted into à Convoluted T-Cells, this transform into T-  Immunoblastic cells, ------->T-Lymphoblast ------> T-Prolymphocytes -------->T-Lymphocytes.

Functions of lymphocytes:

  1.       Formation of Lymphocytes as B and T lymphocytes which takes part in the immunity.
  2.        Production of Ab takes place by B- lymphocytes.
  3.        Filtration of Lymph removes  Particulate matter like Bacteria, Virus, cellular debris, anthracotic pigments and cancer cells.
  4.        Phagocytosis by these lymphocytes.
  5.       They have important role  Role in Inflammation and Infection:

Lymph Node are labile.  Relatively larger at birth,  Modified by stress, adrenal gland , thyroid hormones and  immune response.

·        Biopsy of Lymph Node used for:

  1.   Bacterial Examination where one can do culture and sensitivity(C/S).
  2.   Cytologic imprint for the better differentiation of the cells.
  3.  Histological Examination can differentiate inflammation, metastatic tumor infiltrate, or primary tumor like lymphomas .

Electron microscopy may be done on biopsy material:

  •   Immunophenotyping.
  •  Chromosomal studies.
  •  Gene Rearrangement Analysis.
  •  DNA Ploidy studies

Indications for Lymph Node Biopsy:

  1.  To make a diagnoses in case of Persistent enlargement of the lymph nodes
  2.   To make diagnosis in a patient with PUO, weight loss and enlarged lymph nodes.
  3.    To confirm diagnoses already suspected on other grounds.
  4.     To assess in the extent of spread of known malignant diseases.
  5.       To monitor the progress of disease in patient with malignant lymph nodes.

Precaution for lymph node biopsy:

  1.      Inguinal lymph nodes wherever these are enlarged should be avoided. Take biopsy from other group.
  2.      Always take biopsy from the larger lymph node.
  3.      Axillary and cervical lymph nodes are more representative.
  4.      Superficial small lymph node may slow non-specific hyperplasia whereas deeper node in the same group may show diagnostic feature.
  • Lymph  node with normal picture shows:             
  •   Narrow peripheral sinus.
  •    Sinusoids are not prominent.
  •    Macrophages are not prominent.
  • There are   Small ill-defined germinal centers.
  • There are   Sparse Lymphocytes in Reticular framework.  
  • The   Size is  Small.

Activation of Lymph Node in Acute Disease:

  1. There is increase in the size of lymph node.   
  2. There is dilatation of the sinusoidal  Sinuses.
  3. The  Sinusoids are prominent.
  4. The   Macrophages are increased in number.
  5. There is increased number of   Polys and Necrosis.
  6. The germinal centers are prominent  with increased number of mitosis.

Activation of Lymph Node in Chronic Disease

  1. There is increase in the size of lymph node.
  2. There is increase number of plasma cells and eosinophils.
  3. Also can see above changes seen in acute diseases.

 


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