Direct immunofluorescence staining patterns compared between oral and cutaneous lichen planus.

This retrospective study performed to investigate direct immunofluorescence (DIF) findings in oral and cutaneous lichen planus (LP), and to identify any differences between them. There were 147 patients with a definite diagnosis of LP by clinical and histological criteria, with 87 (59.2%) oral and 60 (40.8%) cutaneous specimens. Of these, 125 (85%) had positive DIF findings, with positive yields being significantly lower in oral (79.3%) than in cutaneous (93.3%) LP. Deposition of immunoreactants at the dermoepidermal junction (DEJ) was significantly greater in oral than in cutaneous LP, and fibrin deposition with shaggy pattern at the DEJ was also significantly greater in oral than in cutaneous LP. Deposition of immunoreactants at colloid bodies (CBs) with or without DEJ was significantly greater in cutaneous than in oral LP. IgM deposition at CBs was commonly detected in both groups. We propose that fibrin deposition with shaggy pattern at the DEJ is the best diagnostic indicator of oral LP.