Biopsy Site Selection
Biopsy site is critical for precise immunofluorescence results...
- Pemphigus, pemphigoid and other subepidermal immunobullous disease: (including all pemphigus subtypes, all pemphigoid subtypes, linear IgA bullous dermatosis, chronic bullous disease of childhood, epidermolysis bullosa acquisita and herpes gestationis): Biopsy perilesional, erythematous skin or mucosa. Perform biopsy directly adjacent to, but not including, a new or active blister. Avoid ulcers, erosions, and bullae. For pemphigoid, avoid distal areas, especially lower extremities where the pemphigoid antigen(s) is/are sparse. Specify perilesional skin on the request form. Accompanying serum for indirect immunofluorescence is particularly helpful diagnostically with these diseases.
- Dermatitis herpetiformis: Obtain a biopsy 3 - 5 mm away from an active lesion of normal-appearing skin. Specify perilesional skin on the request form. More than one biopsy can be helpful because IgA staining may be sparsely distributed. Accompanying serum for endomysial and tissue transglutaminase antibodies is particularly helpful diagnostically with this disease.
- Lupus erythematosus and mixed connective tissue disease: (including systemic lupus erythematosus, discoid lupus erythematosus, subacute cutaneous lupus erythematosus, overlap and mixed connective tissue disease): Biopsy erythematous or active border of new lesion. Specify involved skin on the request form and indicate whether the skin site is sun exposed or non-sun exposed. Avoid old lesions, ulcerated skin, and facial lesions, if possible. Biopsies from both lesional skin and nonlesional, sun-protected skin can be helpful for the diagnosis of systemic lupus erythematosus and mixed connective tissue disease to detect a lupus band. Buttock or medial thigh skin is the preferred site for uninvolved, non-sun exposed skin. Specify uninvolved, non-sun exposed skin on the request form. When sclerodermoid features are present in mixed connective tissue disease, biopsy inflamed area as for lupus erythematosus, specify involved skin and indicate whether it is from a sun exposed or non-sun exposed location.
- Lichen planus and lichenoid reactions including drug reactions: Biopsy involved skin or mucosa of new lesions. Avoid ulcers and old lesions. Specify involved skin on the request form and indicate sun exposed or non-sun exposed.
- Vasculitis and urticaria: Obtain a biopsy specimen from the erythematous, preferably pink, or active border of a new lesion (less than 48 hours old). Avoid ulcers and old lesions. Specify involved skin on the request form. If an appropriate skin lesion is not present for biopsy, diagnostic information may be obtained from uninvolved skin. Nonspecific vascular staining is found in dependent anatomical locations; therefore, avoid lower extremities, if possible.
- Porphyria and pseudoporphyria: Biopsy involved skin of a new lesion. Avoid ulcers, erosions and old lesions. Specify involved skin on the request form.