Biopsy
Consider punch or elliptical biopsy if the wound or ulcer has an atypical appearance (eg an irregular edge, abnormal colour and texture of tissue) or location, or has not responded to therapy. Practice points for undertaking a biopsy are listed in Practice points for an ulcer or wound biopsy. Liaise with a pathologist or microbiologist if an unusual cause is suspected.
Histopathology is required if malignancy or an inflammatory disorder (eg vasculitis, pyoderma) is suspected, and may be useful in the diagnosis of some infections (eg Mycobacterium ulcerans).
Send biopsy specimens for microscopy, culture and susceptibility testing (consider whether to test for specific organisms; see Ulcer and wound infection).
- Biopsy specimens can be used for histopathology, microbiology and (occasionally) immunofluorescence.
- Obtain biopsy specimens from several sites, including the wound edge and main wound area; usually a specimen is taken from each quarter of the wound.
- Put specimens for histopathology in formalin.
- Put specimens for microbiology in sterile water or saline soaked gauze; do not wash the specimen with antiseptic.
- An adequate specimen (eg from a surgical debridement) can be cut in half to be used for microbiology and histopathology.
- A deep skin biopsy of the ulcer edge that includes normal skin is ideal for chronic ulcers with delayed healing, to perform histology, fungal and mycobacterial culture.
- If blisters are present:
- take a biopsy for histopathology of the blister edge and part of the roof. A small intact blister (if present) can provide more information than the edge of a large one
- take a second biopsy from the adjacent (normal) skin for immunofluorescence to exclude inflammatory aetiology (liaise with pathology centre for appropriate transport media).