《Slide 203.》Tuberculosis, Lung

A. Brief Descriptions：

1. Caused by Mycobacterium tuberculosis.

B. Gross Findings：

1. Primary TB – Ghon complex.

2. Secondary TB – in the apex as a small focus of consolidation.

C. Micro Findings：

1. Granulomas (tubercles):

   1. Central caseation necrosis.

   2. Epithelioid histiocytes.

   3. Multinucleated Langhans’ giant cells.

   4. Fibroblasts and lymphocytes.
      　

E. Reference：

1. Robbins Pathologic Basis of Disease, 6^th ed.  P.379-352.

 

 

 

【 Fig. 203-1 (LP)】Multiple confluent or separated nodules are seen in lung parenchyma. Note thickened and congested interstitium. The alveoli show emphysematous change.

　

 

【 Fig. 203-2 (LP)】Caseating granuloma (tubercle). The center of the tubercle contains caseous necrotic debris (amorphous eosinophilic substance) and is surrounded by epithelioid histiocytes and lymphocytes.

　

 

 

【 Fig. 203-3 (LP)】The center of the tubercle is composed of caseating necrotic debris. Note the elongated epithelioid histiocytes around the caseating center.

 

 

【 Fig. 203-4 (LP)】A caseous granuloma with caseating necrotic center, epithelioid histiocytes and a typical Langhans’ giant cell (middle left). Note the nuclei of the Langhans’ type giant cell lined in horseshoe arrangement.

 

 

 

【 Fig. 203-5 (HP, acid fast stain)】The acid fast stain highlights bacilli of Mycobacterium species (pink color) (Most commonly M. tuberculosis).