 Properly
performed skin biopsies with appropriate clinical history can provide
the clinician with valuable diagnostic and treatment information.
The practice of dermatopathology requires clinical-pathologic correlation,
especially for the evaluation of inflammatory skin disorders.
Please Consider the Following Recommendations:
(Click links below)
Describe
gross lesions How to perform
an appropriate biopsy Pigmented
lesions Lesions
when inflammatory dermatoses are present Avoid biopsy
of excoriated or traumatized lesions If an eruption
is generalized Biopsies
of bullae Submit biopsy specimens
in the appropriate volume of formalin
1. Describe
gross lesions thoroughly.
Provide information regarding the distribution, duration, estimated
number and type of lesions. A clinical differential diagnosis is
valuable information in all types of skin disorders, but particularly
for inflammatory conditions. Various inflammatory dermatoses may
have similar histologic findings, and an accurate interpretation
is dependent upon clinical information. If the lesion is pigmented
and clinically suspicious for melanoma, describe recent changes
and measure the size of the lesion.
2. Perform a biopsy procedure appropriate
for the depth of the suspected process.
Inflammatory dermatoses are evaluated based upon the pattern and
distribution of inflammation. Ideally, both the superficial and
the deep dermis should be examined. Punch and incisional specimens
provide the best information. If panniculitis is suspected, then
an incisional specimen which includes the subcutaneous fat is required.
3. Pigmented lesions that are suspicious
for melanoma should be sampled by excision when possible.
Superficial shave biopsies and small punch specimens of atypical
pigmented lesions are fraught with difficulty and may lead to medicolegal
liability. A malignant melanoma cannot be accurately microstaged
(Breslow thickness) if it is transected. Pathologic micro staging
provides important prognostic information and helps guide subsequent
therapy. A punch biopsy is acceptable if the entire lesion and a
small border (1-2 mm) of normal skin can be obtained. However, it
is preferable that lesions suspected of being melanoma be removed
by an elliptical biopsy, which encompasses the entire lesion with
a border (1-2 mm) of uninvolved skin and subcutaneous fat.
4. Sample well developed lesions
when inflammatory dermatoses are suspected.
Lesions vary in histologic and appearance at different stages of
their evolution. It is best to sample a fully developed lesion,
which will include the most characteristic pathologic features of
the disease. There is one exception to this rule. Vesicular, bullous
or pustular dematoses are best sampled as early intact lesions no
older than 24-48 hours.
5. Avoid biopsy of excoriated or
traumatized lesions.
Secondary changes induced by scratching alter characteristic histopathologic
features.
6. If an eruption is generalized,
than sample the lesions on the trunk, arms, or upper legs.
The elbows, knees and lower leg should be avoided. Elbows and knees
are subject to trauma and friction. The lower leg may have stasis
vascular changes which can complicate interpretation.
7. Biopsies of bullae should include
a portion of the blister and adjacent normal skin.
A biopsy through the center of a bulla can lead to the loss of the
epidermis. Ideally, vesicles should be removed by a punch biopsy
in their entirety.
8. Submit biopsy specimens in the
appropriate volume of formalin which is 10-20 times the volume of
the specimen. Optimal histology is dependent upon good
fixation.
If you have any specific questions regarding the biopsy procedure,
please do not hesitate to call.
Cora S. Humberson, M.D.
Pacific Rim Pathology Medical Group, Inc.
(858) 939-3660
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