Information on the skin biopsy
Biopsy techniques
The Punch Biopsy
In view of its simplicity of handling, the
punch has become the standard instrument for skin biopsies.
In association with disinfection of the skin, a conduction
or local anaesthesia is performed, for which the anaesthetic
should not be sprayed directly at the piece of tissue to be
removed, in order to prevent any 
artifacts.
The insertion location should be outside the biopsy area.
The
Punch
is generally placed into the fatty tissue; the tissue-cast
for removal is thus completely separated from the collagen
fibres of the reticular dermis, and lifts above the level
of the surrounding skin after withdrawal of the punch. If
one then presses the surrounding skin downwards with the flat
side of the surgical scissors, one can easily clear away the
tissue-cast to its base in the fatty tissue. It is often also
necessary to lift the tissue-cast with tweezers or a needle.
This must be done with great care, as even slight pressure
is liable to lead to contusion artifacts that impair the ability
to assess the biopsy preparation.
Contusion
artifacts are to be expected especially where there
is dense infiltration, for example where there are lymphomas
or pseudo-lymphomas, in which assessment of individual cells
is particularly important. In cases of clinically tough-looking
lesions, the tissue must therefore be handled extremely carefully!
In the case of punches with a diameter of
2–3 mm, one can generally avoid closing up the wound.
Covering up the wound is carried out with compresses or with
a small hydrocolloid tape. Hydrocolloid tapes have the advantage
that they do not need to be changed. In some regions, larger
punches are also possible without closing up the wound. This
applies for example to the concave areas of the face (e.g.
bridge of the nose, sides of the nose), where skin blemishes
heal up well.
Closing
up of wounds is generally not required in the case of the
mucous membranes either.
In cases of punches with a diameter of 4
mm, the resulting wounds are closed up with stitches or stapled
plaster-strips in most cases. This is particularly suitable
for the oval-shaped wounds that one obtains if one stretches
the skin vertically between fingers along the course of the
tension-lines before
removing
the round punch biopsy. The resulting scars are
barely visible.(10)
next
page "the Spindle biopsy"
previous
page "Biopsy techniques"
back
to the Index of contents |
