The Skin Biopsy

• In no other field of medicine is tissue for histologic examination so easily accessible.

• As a result, the skin biopsy has become an integralcomponent of dermatologic diagnoses

Skin biopsies are performed for a multitude of reasons, including:

• uncertainty about the clinical diagnosis• to investigate a poor response to therapy• to exclude or investigate the evolution of one

condition into another• to investigate symptoms in the absence of

clinically recognizable disease.

• the process of securing appropriate tissue involves more than the mere mechanical removal of a specimen

Pitfalls of Skin Biopsy:

Site Selection:

• First step : Identify an unadulterated primary lesion (Exclude lesions with secondary changes)

• Second Step: choose Well developed but Fresh Lesion (It show the most characteristic and diagnostic histopathology ( Except : LCV)

Site Selection:

• 3rd Step: Obtain from central aspect of a primary lesion (except ulcer or subtle change as anetoderma)

• 4th Step: selection of a proper biopsy site mayalso be influenced by knowledge of the

underlying pathology and pathophysiology of the most likely diagnoses.

Biopsy techniques:

• Superficial (tangential shave)• deep shave (saucerization)• punch • incisional/excisional

the technique: 1-must obtain tissue from the level of the skin

or subcutaneous tissue where the pathologic changes are expected

2- simultaneously balancing concerns of cosmesis and morbidity.

• Panniculitis: Do not perform shave biopsy

• Verruca or Skin Tag: Do not perform Excision

Curettage

• a curette 3-5 mm in diameter is held like a pencil and drawn with pressure under the

lesion (if epidermal) or through the lesion (e.g. presumed BCC).

• This type of biopsy assumes that healing will be by second intention.

• The resulting scar is usually minimal

Shave Biopsy:

• Perform when:1-the pathologic process is primarily

epidermal2- when removing exophytic benign

lesions

• E.g. intradermal melanocytic nevi or pigmented actinic keratosis or Bowen's disease versus macular

seborrheic keratosis)

Deep shave/saucerization biopsy

• Deeper variant of the superficial shave biopsy

• Often used to biopsy neoplasms (e.g. SCC versus hypertrophic AK)

when properly performed, its diagnostic value is nearly equal to most incisional/excisional procedures

Punch biopsy:

• Perform when suspected pathology is within the dermis

and • when a partial sampling will be

representative of the entire lesion or process.

Punch Biopsy:

• Poor Results:• assessment of deeply

infiltrating tumors or the full thickness of the subcutaneous fat.

• Partial punch biopsies of melanocytic neoplasms can lead to erroneous diagnoses.

Incisional /excisionalbiopsy• Incisional: removal of a

portion of a lesion (e.g. Panniculitis)

• Excisional: Removal of the entire lesion via a scalpel and

standard surgical techniques(e.g. Melanoma)

Post-procedure handling of the biopsy

• Avoid crush artifact especially for small punch biopsy.

• Lymphocytes are particularly susceptible to crush artifact, and when present, it may be impossible to render an accurate diagnosis.

• For routine histologic exam: place the specimen in the formalin container (volume 10x to 20x)

• Microbial culture: place in the non-bacteriostatic saline container and deliver immediately to LAB.

• For DIF: Flash Frozen or use Michel Solution

Other Information:

• Age and sex of the patient

• Anatomic site• Pertinent and precise

physical findings• Differential diagnosis• Treatments• Drawings or clinical

photographs