A. Caseous necrosis 

Caseous necrosis: 

Is a distinctive form of necrosis seen in cases of tuberculous infection. Caseous refers to the cheese like appearance of the friable white appearance of the areas of necrosis. It includes collection of fragmented or lysed cells and amorphous debris. Caseous necrosis is generally enclosed within a distinctive inflammatory border consisting of modified macrophages, the epithelioid cells surrounded by lymphocytes. This collection is referred to as the granuloma.

Tubercular lymphadenitis: 

Lymph nodes can be site of involvement in either primary or secondary tuberculosis and is characterized by caseating granulomatous inflammation. 

History:

40 yrs male presented with fever, productive cough and loss of appetite.

Key Questions & Answers

1) Describe the gross features of the specimen.

1. Enlarged, matted group of lymph nodes.

2. C/S shows yellowish white, circumscribed cheesy area of caseation.

2) Identify the microscopic features of the given slide.

1. Lymph node with areas of amorphous, granular, eosinophilic material with nuclear debris(Areas of caseation) amidst epithelioid cell granulomas.

2. Lymphocytes are seen in the periphery with few Langhans giant cells.

3) Diagnose the pathological condition correlating the history, gross and microscopic features. 

Tuberculous lymphadenitis

4.What are the other types of necrosis? 

• Coagulative necrosis

• Liquifactive necrosis

• Fat necrosis

• Fibrinoid necrosis

5.In which disease it is seen? 

Tuberculosis

6. What is the special stain used for the confirmation of the diagnosis.

AFB

7. Mention the primary sites of the above lesion.

1. Lungs 

2. Intestines 

3. Lymph nodes

4. Skin

5. Eye