A skin biopsy is tested by removing a small piece of skin, processing it in a lab, and then examining it under a microscope.
Here's a breakdown of the process:
1. Skin Sample Collection
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A dermatologist or surgeon removes a small skin sample. The specific technique used depends on the suspected condition, the size, and location of the skin lesion. Common techniques include:
- Shave Biopsy: The top layers of skin are shaved off using a blade.
- Punch Biopsy: A small, circular piece of skin is removed using a special tool.
- Incisional Biopsy: A wedge of skin is removed.
- Excisional Biopsy: The entire abnormal area of skin (and sometimes a border of normal-looking skin) is removed.
2. Lab Processing
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The skin sample is sent to a pathology lab, where it undergoes processing:
- Fixation: The tissue is preserved, typically with formalin, to prevent decomposition and maintain its structure.
- Embedding: The tissue is embedded in paraffin wax, which provides support during sectioning.
- Sectioning: A microtome is used to cut the paraffin block into very thin slices (sections), typically a few micrometers thick.
- Staining: The sections are stained with dyes (usually hematoxylin and eosin or H&E) to highlight different cellular components and structures, making them visible under a microscope. Special stains can also be used to identify specific organisms or substances.
3. Microscopic Examination
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A pathologist, a doctor specializing in diagnosing diseases by examining tissues and cells, examines the stained skin sections under a microscope.
- The pathologist looks for abnormalities in the skin cells, such as:
- Inflammation
- Infection
- Abnormal cell growth (e.g., cancer cells)
- Changes in skin structures (e.g., collagen, blood vessels)
- The pathologist writes a report detailing the findings, which is then sent to the referring physician.
- The pathologist looks for abnormalities in the skin cells, such as:
4. Diagnosis
- The referring physician (usually a dermatologist or the doctor who ordered the biopsy) reviews the pathology report and discusses the results with the patient. The biopsy results help determine the diagnosis and guide treatment.
