Lymphadenopathy Overview

Study Notes

Lymphadenopathy refers to a disease of the lymph nodes, characterized by abnormality in size or consistency.
Lymphadenopathy can either be inflammatory or neoplastic in nature.

Acute non-specific Lymphadenitis: Occurs in nodes draining acutely inflamed areas, such as during acute suppurative tonsillitis.
- Grossly: Acutely inflamed nodes are enlarged and tender.
- Microscopically: Large germinal centers are present; Neutrophilic infiltration with abscess formation can be seen in severe cases.

TB Lymphadenitis:
- Common cause of lymph node enlargement, usually a primary infection in children.
- Commonest Sites:
  - Cervical LNs: Infected from tonsils.
  - Mediastinal LNs: Infected with primary pulmonary TB.
  - Mesenteric LNs: Infected due to ingestion of infected milk ("Tabes mesenterica").
- Microscopically:
  - Early Tuberculous Lymphadenitis: Infiltration by multiple small, pale tubercles formed of aggregates of epithelioid cells, few Langhans giant cells, and minimal caseation.
  - Caseating Tuberculous Lymphadenitis: Most nodal tissue is replaced by areas of caseous necrosis with multiple small tubercles at the periphery.

Formation: Accumulation and liquefaction of caseous material, surrounded by TB granulation tissue and fibrosis.
Complication: Complicates TB of lymph nodes, bones, joints, and epididymis.
Progression: May open to the outside, leading to multiple sinuses.

An inflammatory disease of unknown cause: Affects multiple organs, primarily the lungs and lymph nodes.
Formation: Abnormal masses (non-caseating granulomas) are formed in different organs.
Microscopically:
- Well-circumscribed epithelioid granulomata with giant cells surrounded by lymphocytes.
- Two characteristic inclusions inside giant cells:
  - Schaumann bodies: Laminated calcified bodies.
  - Astroid bodies: Star-shaped inclusions.
- Fibrosis is a common feature.

Caused by the bacterium Bartonella henselae.
Carried by cats: Infection does not make cats sick but can cause symptoms in people through scratches or bites.
Lymph node presentation: Swollen lymph nodes forming stellate abscesses.