A Christmas lesson: biopsy techniques for the young clinician.

Skin biopsy 1 Always inject a large volume of local anaesthetic into the area to be biopsied. The more rapid the better, as this really distorts the tissue planes making microscopic evaluation a real challenge. 2 Always biopsy the centre of any ulcer as this will guarantee that the pathologist will not be able to differentiate between a benign or malignant process as he enjoys the vista of necrotic inflammatory tissue. 3 The biopsy specimen should always be razor-thin. Never include the underlying dermis or subcutaneous tissue as this may lead the pathologist to a correct diagnosis. 4 If at all possible inject a tattoo pigment marker before your biopsy. Particularly in the case of Kveim biopsies this extends the pathologist's ability to make a diagnosis without the help of artificial light.