for Undergraduate Medical Students (MBBS)

1. Lymphoreticular system
Dr.CSBR.Prasad, M.D.

2. Chronic lymphadenitis
1. Follicular Hyperplasia
2. Paracortical (Interfollicular) Hyperplasia
3. Sinus histiocytosis
Granulomatous inflammation

3. Chronic lymphadenitis
Follicular Hyperplasia
• Secondary follicles with germinal centers
• Parafollicular areas – plasma cells,
histiocytes.
• Eg: Rhematoid arthritis, Toxoplasmosis, HIV
infection
• DD: Follicular lymphoma
– Preservation of architecture
– Marked variation in size & shape of lymphoid
follicles
– Frequent mitosis, TBM

4. Chronic lymphadenitis
Paracortical (Interfollicular) Hyperplasia
•Reactive changes in T cell regions
•Infectious mononucleosis
• Other Viral infection
•Immunological reaction against drugs
•Dermatopathic lymphadenitis

5. Chronic lymphadenitis
Sinus histiocytosis
• Sinuses are dilated & prominent
• LN draining infections & neoplastic
processes
• Rosai – Dorfman disease,
Langerhans’ cell histiocytosis,
Whipple’s disease

6. Chronic lymphadenitis
Granulomatous inflammation
– Infections – Tuberculosis, leprosy, syphilis,
fungus, sarcoidosis, brucellosis, LGV
– Foreign body reaction
– LN draining carcinomas
– Hodgkin’s lymphoma
•Presence & type of necrosis
•Langerhans giant cells – size & number
•Size, shape & distribution of granulomas
•Associated changes in intervening tissue

10. Sarcoidosis
• Sarcoidosis is an unexplained derangement of
the immune system
• Distinctive granulomas form in lymph nodes and
other locations such as lungs, spleen, liver et.c.
• Low CD4 counts and >ACE levels
• Epithelioid granulomas Schaumann's or asteroid
bodies

11. Sarcoidosis

12. Metastatic cancer
• Carcinomas frequently metastasize to
lymph nodes causing lymphadenopathy
• Sinus histiocytosis / Granulomas
• Sentinel lymphnode
• Virchow’s lymphnode

13. AIDS Related
lymphadenopathy
• Mycobacterial & other opportunistic
infections
• Kaposis sarcoma
• Malignant lymphoma
• Florid reactive hyperplasia
– Follicle lysis – Invagination of mantle
lymphocytes into germinal centres
– polykaryocytes

14. INFECTIOUS MONONUCLEOSIS
• EBV
• Effacement of architecture
• Marked proliferation of immunoblasts,
immature plasma cells
• RS like cells – Basophilic nucleoli.
Paranuclear hof

15. METASTATIC DEPOSITS
• Usually carcinomas metastasize to LNs
• Produce firm, painless enlargement of the lymph nodes,
similar to lymphomas.
• Far more common than lymphomas
• Initially subcapsular deposits
• Deposits in medullary region are indicative of blood spread
• Sarcomas that may spread thru lymphatics include:
-- Synovial sarcoma
-- Lymphomas
-- RMS
• Virchow’s lymphnode

16. Seen here are sections across very enlarged nodes that contain
metastases. Metastatic tumor can produce a firm, homogenous white
appearance in nodes up to 1 to 2 cm. The cut surface is variegated.

17. Seen here are neoplastic glandular configurations representing metastatic
adenocarcinoma. The nodes draining from the primary site of a carcinoma are
most commonly involved, but distal nodal groups may be involved as well.

18. Spleen

19. Spleen
• Filtration
• Immune function
• Source of hematopoiesis
• Reserve pool

20. Hypersplenism
• Splenomegaly
• Anemia, leukopenia,
thrombocytopenia, associated with BM
hyperplasia
• Correction of cytopenia by
splenectomy

21. Splenomegaly
• Infection
– IMN
– TB
– Typhoid
– Brucellosis
– CMV
– Syphilis
– Malaria
– Histoplasmosis, Toxoplasmosis, Kalaazar,
• Congestive
– Cirrrhosis
– Portal/ splenic vein thrombosis
– Cardiac failure
• Lymphohematogenous disorders
– HD, NHL, Multiple myeloma, MPD, Hemolytic anemias

22. Splenomegaly
• Immunological
– RA
– SLE
• Storage disorders
– Gaucher’s, Nieman- pick disease, MPS
• Others
– Amyloidosis
– Primary & secondary neoplasms

23. Massive Splenomegaly
A spleen >1000 gm / crosses the midline
• CML
• Hairy cell leukemia
• Myelofibrosis
• Others:
Storage disorders
Malaria
Leishmaniasis
Schistosomiasis

24. This is a markedly enlarged spleen (the ruler is 15 cm long). Such massive
splenomegaly is usually indicative of some myeloproliferative disease such as chronic
myelogenous leukemia or myelofibrosis. There are subcapsular yellow-tan infarcts.
Congestive splenomegaly (as with portal hypertension in cirrhosis of the liver)
is unlikely to increase the size of the spleen over 800 gm. A spleen >1000 gm
suggests a myeloproliferative, lymphoproliferative, or hematopoietic disorder.

25. At high power are large pale pink macrophages. Numerous clusters of these
macrophages are present in an enlarged spleen of a child. This appearance is typical for
a storage disease. In this case, the patient had Gaucher disease.

26. Thymus

27. Thymus
• Pyramid shaped, encapsulated, two
fused lobes
• Anterior superior mediastinum
• Epithelial cells, lymphocytes, Hassall's
corpuscles

28. Thymoma
Tumour of thymic epithelial cells
• Benign Thymoma
• Malignant Thymoma
– Type 1
• Cortical, epithelial cells
• Immature thymocytes
• Locally invasive
– Type 2 ( Thymic carcinoma)
• Squamous cell carcinoma
• Lymphoepithelioma like carcinoma
• Sarcomatoid variant
• Basaloid carcinoma
• Clear cell carcinoma

29. Thymoma - C/F
• Compressive effects
• 30-45% cases – Myasthenia gravis
• Acquired hypogammaglobulinemia,
pure red cell aplasia, Grave’s disease,
pernicious anemia, cushing’s
syndrome