Describe the indications for an excisional or incisional biopsy.

Excisional or incisional biopsies are usually elliptical in shape and typically deeper than punch biopsies. An excisional biopsy is the complete removal of a lesion into the fat, followed by layered closure of the skin. It is particularly helpful in the complete removal of malignancies, such as malignant melanoma, basal cell carcinoma, and squamous cell carcinoma. Excisional biopsies can also be performed when the cosmetic result is felt to be superior to that of a punch biopsy. An incisional biopsy is the incomplete or partial removal of a lesion. If a suspected malignancy is felt to be too large to remove with simple surgery, an incisional biopsy is used to remove the thickest or clinically most worrisome portion for diagnostic pathologic examination. It is also useful for diagnosing panniculitis, sclerotic, or atrophic lesions in which it is important to compare normal adjacent skin to that of the lesion, and to lesions with active expanding borders, such as pyoderma gangrenosum.

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