This document discusses various pathological conditions that can present as lymphadenopathy (enlarged lymph nodes). It describes follicular hyperplasia, paracortical hyperplasia, and sinus histiocytosis as types of chronic lymphadenitis. Granulomatous inflammation of lymph nodes can be seen in infections like tuberculosis or sarcoidosis. Metastatic cancer and infectious mononucleosis can also cause lymph node enlargement. The document further discusses conditions involving the spleen and thymus gland.

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