If a gingival biopsy is required, one should be careful to take the following steps into consideration (Figure 5):
- The specimen should be taken apical to the free gingival margin, since most marginal areas are inflamed and the inflammatory process may mask the histopathologic features necessary to establishing the correct diagnosis.
- Local anesthesia is achieved being careful to avoid direct injection into the biopsy site to prevent hemorrhage, cellular distortion and epithelial disruption in the biopsy area.
- Often it is necessary to submit tissue samples for both histologic and direct immunofluorescence evaluation since the pathologic process may represent an autoimmune condition such as mucous membrane pemphigoid or pemphigus vulgaris.54,56,75
- Oral lichen planus has autoimmune properties found within lesions but lacks the systemic immunologic features confirming autoimmunity. Nevertheless, immunofluorescence studies of oral lichen planus may be indicated because a linear pattern of anti-fibrinogen at the basement membrane zone and the presence of immunoglobulins in cytoid bodies are supportive of the diagnosis.10,14,23,75
- Other mucocutaneous diseases such as chronic ulcerative stomatitis, lichen planus pemphigoides, graft versus host disease, and discoid lupus erythematosus may mimic the clinical and histological features of oral lichen planus so DIF results may be of great value in supporting the diagnosis of OLP.90
- Traditional biopsy protocol calls for incorporating lesional and perilesional tissue in the biopsy procedure. However, in DG, lesional sites often have lost their surface epithelium and the perilesional area immediately adjacent to the lesion is extremely friable. This coupled with the trauma of the biopsy itself may result in epithelial sloughing and diagnostic failure. Sano, et al. defined perilesional tissue as the area within 1 cm of the lesion, while sites beyond 1 cm of the lesions are considered distant.79 They found no significant difference in DIF findings between the perilesional (66.1%) and distant sites (64.7%). They also suggested separate H&E and DIF biopsies were preferable to the traditional practice of splitting a single biopsy for the two analyses.