《Slide 4.》Brain abscess, Cerebrum

A. Brief Descriptions：

1. Types:

   • Emboli cerebral abscess from infected foci in body 40%.

   • Direct extension of cerebral abscess from adjacent infected foci.

   • Relate to cerebral trauma, 30%.

   • Idiopathic abscess, 20%.

2. Stages :

• Infected thromboembolus forming a necrotic foci.

• Acute cerebritis.

• Liquefaction & purulent exudates.

• Heavy infiltration (2 days).

• Granulation at margins (5-7 days).

• Encapsulation.

B. Gross Findings：

1. Discrete lesions with central liquefactive necrosis, surrounding by fibrous, collagenized response and edema.

C. Micro Findings：

1. Necrotic, purulent center.

2. Capsule of granulomatous tissue & fibrosis (capillaries proliferation, infiltration, Gitter cells...).

3. Surrounding reactive brain with edema & gliosis.
   　

D. Others:

1. Cerebritis: focal inflammation of brain parenchyma.

2. Myelitis: focal inflammation of spinal cord.

3. Focal pyogenic cerebritis.

4. Emboli suppurative encephalitis.

E. Reference：

1. Robbins Pathologic Basis of Disease, 6^th ed.  P.349-352.

 

 

【 Fig. 4-1 (LP)】The normal architecture of cerebrum is destructed.

　

 

 

 

【 Fig. 4-2 (LP)】The necrotic area is in the left, the normal cerebral cortex in the right, and a thick fibrous band lined between them.

　

 

 

【 Fig. 4-3 (LP)】The normal cerebral cortex (left) and the fibrous capsule (right) surrounding the necrotic area (not shown here). Note the rather dense and parallel fibrous bundles of the capsule.

　

 

 

【 Fig. 4-4 (LP)】The fibrous capsule. Note the more outside of the capsule (left side in this picture), the more thickening of the fibrous bundles.

　

 

 

【 Fig. 4-5 (LP)】The necrotic center (right) is surrounded by granulation tissue (left). Note foamy histiocytes (Gitter cells) aggregate in the outermost of the necrotic area.

　

  

 

【 Fig. 4-6 (HP)】The necrotic area is composed of cell debris, nuclear dusts, inflammatory cells (most frequently PMNs) and Gitter cells (foamy histiocytes in the CNS).