VLD 421: Veterinary Clinical Biochemistry and Laboratory Diagnosis-II (0+1)

DIFFERENT METHODS OF BIOPSY

• Final needle aspiraton biopsy
• Punch biopsy
• Incisional biopsy
• Excisional biopsy

FINE NEEDLE ASPIRATION BIOPSY

• Procedure
  • Fine needle aspiration biopsy can be performed using 23-25 G needle with 5 -20 ml syringe.
  • A dry needle attached tightly to the syringe is inserted into the surface lesion/lymph node enlargement (Tumour mass/lymph node).
  • The cellular mass and tissue fluids are aspirated and smears prepared immediately on glass slide are either wet fixed in absolute alcohol or dry fixed.
• Precaution
  • Both syringe and needle should be absolutely dry, since a small quantity of fluid may cause cellular distortion and artifacts.
• Application
  • To evaluate inflammation, hyperplasia and primary or metastatic tumour cells and diagnose theileriosis (Koch’s blue bodies can be seen by Leishman’s staining). 

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PUNCH BIOPSY

A core of tissue is procured by punching with a special needle.

• Application
  • Most commonly used for externally palpable mass.
• Instrument needed
  • True cut needle / Franklin modified Vim- Silver-Mann needle.

INCISIONAL BIOPSY

• Principle
  • A small portion of a lesion is surgically removed.
• Application
  • Preferred method for ulcerated and necrotic lesions and skin lesions.

EXCISIONAL BIOPSY

• Method
  • Removal of a relatively large specimen of tissues.
• Advantages
  • Both treatment and diagnosis are incorporated. 
  • This method permits examination by conventional cytological  and histological methods.
• Application
  • Excisional biopsy is useful in case of skin lesions and tumours.

PROCESSING OF SPECIMEN

• Blot the specimen to remove excess blood. 
• Make impression smears for cytological examination. 
• Submit a portion of tissue for cultural examination.
• Press gently the other portion on a piece of blotting paper to flatten and  orient the tissue for histopathologic examination. 
• Place the tissue with the paper in 10% neutral formalin. 
• Process the tissue by routine paraffin embedding technique. 
• Cut sections of 5 µm thickness and stain with Haematoxylin and Eosin.