Skin Biopsy Lab Flashcards
Why biopsy?
to make a DX of any swelling of tissue
4 reasons to biopsy..
- confirm DX before administering potentially harmful drugs
- determine cause of non-healing wounds
- quickly determine etiology of aggressive or unusual skin lesions
- determine cause of lesions that develop during the course of therapy
When should you biopsy?
When lesions are ACTIVE or BEFORE use of a therapy that might alter the histologic appearance of the lesions
What 2 types of drugs may alter the histologic appearance of skin lesions?
corticosteriods
immune-modulatory drugs
antimicrobials
It is best to biopsy the ___ spectrum of lesions present.
full
Where to biopsy?
multiple cutaneous sites that represent the full range of lesions (both 1ry & 2ry)
Be sure to label each sample with the _____ it was collected from.
location
How do you prepare a site for biopsy?
- trim hair short (gently)
2. DO NOT surgically prepare the site (disinfect w/ 70% alcohol & let air dry)
Technique to biopsy lesions.
- multiple samples representative of the range of lesions
- properly label w/ location
- always include crusts, if present
Technique for alopecic conditions.
- collect sample from most alopecic area
2. draw line in direction of hair coat growth
Technique for ulcerative & de-pigmenting lesions.
collect sample from the junctional zone –> margin btwn normal & abnormal skin
Size of punch biopsy for haired skin?
6-8 mm punch
Size of punch biopsy for periocular skin, paw pads, or nasal planum?
4-6 mm punch
Technique for incisional biopsy.
- take representative sample of the entire lesion + some normal skin
- elliptical incision –> easier to stitch up
How should skin biopsies be fixed? (TQ)
in 10% buffered formalin immediately after collection
fix:tissue ratio= 10:1
