General Pathology

1. Prof.Dr.
Khalil Hassan Zenad
Aljeboori
Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
Lecture 28
PATHOLOGY OF LYMPHOID
SYSTEM

2. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
Reactive hyperplasia:
Any immune response against the infectious and non infectious
inflammatory stimuli is associated with enlargement of lymph
node(lymphadenopathy), the infections are numerous causing
lymphadenitis may be acute or chronic a similar histological
appearance with different etiologies is seen.
Diseases of lymph nodes:

3. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
Grossly:
Lymph node enlarged, swollen.
Microscopically:
Multiple lymphoid germinal centers with mitotic figures when the
cause is pyogenic bacteria. Neutrophils infiltration in center and
periphery of lymphoid follicles and in lymphoid sinuses. Necrosis
and abscess formation in the lymph node.
 Acute nonspecific lymphadenitis:

4. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
This disorder present at three patterns:
1. Follicular hyperplasia:
Associated with infections that activate B cell area (the follicle) with create germinal center and scattered
macrophages and dendritic cells (Ag presenting cells).
Causes of follicular hyperplasia:
1. Rheumatic arthritis
2. Toxoplasmosis
3. HIV infection (early stage)
This type of follicular hyperplasia is confused with follicular lymphoma.
2. Parafollicular hyperplasia: or (paracortical hyperplasia):
In a zone situated between the cortex and the medulla which contain T cells responsible for CMI. Reactive changes
within T cell area showed microscopically expanded zone between the cortical follicles. On immune activation the T
cells in this region transform into large proliferating immunoblasts that can efface B cell follicular region.
 Chronic nonspecific lymphadenitis:

5. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
1. Viral infection (EBV)
2. Following vaccination
3. Reactions against drugs.
3. Sinus histiocytosis:
There is distention of the lymphatic sinuses with marked hypertrophy of lining
endothelia and infiltrating of macrophages, some histiocytes encounter in lymph
node draining cancer, may represent immune response to tumor cells.
Parafollicular hyperplasia encounter in the followings:

6. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
1. Infections such as:
a) T.B
b) Atypical mycobacteriosis
c) Sarcoidosis
d) Fungal infections
e) Syphilis and leprosy
f) Mesenteric lymphadenitis
g) Cat-scratch disease
h) Brucellosis
2. Foreign body reactions- against any foreign body.
3. Malignancy- occur in relation with it granuloma lymphadenitis, whether the neoplasm is primary
(Hodgkin’s and non-Hodgkin’s lymphoma or secondary metastatic carcinoma. Granuloma in lymph
node occur when the lymph node is involved by malignancy or not.
Granulomatous lymphadenitis:
A large number of diseases associated with granuloma in lymph node (granulomatous lymphadenopathy)
include:

7. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
Two groups of lymphoma:
1. Hodgkin’s lymphoma
2. Non- Hodgkin’s lymphoma.
The behavior and treatment of Hodgkin’s lymphoma differ from those of most non-Hodgkin’s lymphoma,
thus making the distinction between the two tumors of practical importance.
The WHO classification embraces all lymphoid neoplasms, including leukemia and multiple myeloma and
separated them on the basis of origin into three major categories :
A. Tumors of B-cells
B. Tumors of T-cells and NK cells
C. Hodgkin’s lymphoma
Lymphoid tumors:

8. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
Both A and B tumors of B and T cells related with non- Hodgkin’s type of lymphomas the majority of these lymphoid
tumors include:
1. Precursor B and T cell lymphoblastic leukemia/lymphoma.
2. Small lymphocytic lymphoma/ chronic lymphocytic leukemia (SLL/CLL)
3. Follicular lymphoma
4. Diffuse large B-cell lymphoma
5. Burkitt lymphoma
6. Multiple myeloma and related plasma cell dyscrasias
7. Mantle cell lymphoma
8. Hodgkin’s lymphoma
C.Hodgkin’s lymphoma:
It is group of tumors that arise in single lymph node or chain of lymph node, spread characteristically in a stepwise
fashion to the anatomically contiguous nodes. Although it is separated entity from non-Hodgkin’s lymphoma,
molecular studies have shown that it is tumor of B cell origin and it account for 30% of all lymphoma.

9. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
. Nodular lymphocytic predominant HL: in which the (RS) cells are B-Cells reacting
with CD20 and CD79a.
. Classical Hodgkin’s lymphoma: are subclassified into 4 pathological subtypes
based on reed-stenberg cell morphology and composition of the reactive cell
infiltrate the lymph node, nearly all RS cells derived from B cells but show different
markers CD15 and CD30. The back ground lymphocytic are T-cell except in
lymphocytes rich variant where they are mainly B cells.
Classification of Hodgkin’s lymphoma: into:

10. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
1. Nodular sclerosis HL
2. Mixed cellularity type HL
3. Lymphocytic depletion (rare) HL
4. Lymphocytic rich (rare) HL
The histological diagnosis of HL rests on the identification of RS or their variant in
appropriate background of reactive cells. Immunophenotyping play a role in helping
to distinguish HL from reactive conditions and other forms of lymphoma (NHL).
Involvement of the spleen, liver, bone marrow and other organs appear in the course
of the disease (HL).
Under these heading are the following subtypes:

11. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
Extranodal marginal zone lymphoma:
B cell tumor occur in mucosal associated lymphoid tissue (MALT) such as salivary gland,
lungs small intestine and large intestine.
It occur in a set of autoimmune disorders (such as sjogren syndrome Hashimoto's
thyroiditis, chronic infections with Helicobacter pylori-suggesting that sustained Ag
stimulation contribute the tumor development. In case of H.pylori associated gastric
MALT lymphoma, eradication of the H.pylori with antibiotics therapy often lead to
regression of tumor, when arising in other site (MALT) the tumor can be cured by
surgery or radiotherapy .
Miscellaneous lymphoid tumors:

12. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
Mycosis fungoides and sezary syndrome:
Is a cutaneous T cell lymphoma involve the skin composed of CD4+ T-cells. it begin a
reddish rash in skin then develop to plaques phase and tumor.
Microscopically:
Infiltration of epidermis and upper dermis by neoplastic T-cell with infolding nuclear
membrane. With progress of the disease involvement of lymph and visceral organs.
There is exfoliative erythroderma and tumor cells (sezary cells) in blood.
Peripheral T-cell lymphoma:
Group of tumors make up about 15% of NHL, it present as a disseminated disease are
aggressive and poorly respond to therapy.

13. PRESENTATION
ENDS
Copyrights © 2017 l Aliraqia University l Dentistry l Pathology l Prof.Dr. Khalil Hassan Zenad Aljeboori.
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