Junction-Associated Laminin-R/RPSA Immunoreactivity in Electrical Marks: A Morphological and Immunohistochemical Study

Cutaneous electrical marks may provide the principal localized morphological evidence of contact with an electrical conductor, but their histopathological interpretation remains challenging. We investigated the topographical relationship between dermo-epidermal detachment and junction-associated Laminin-Receptor/Ribosomal Protein SA (Laminin-R/RPSA) immunoreactivity in 25 full-thickness skin specimens from documented fatal electrocution cases. Detachment on hematoxylin and eosin (H&E) staining was initially classified as present, absent, or equivocal, with discordant or equivocal assessments subsequently adjudicated by a supervising observer. After adjudication, detachment was present in 22 specimens (88%) and absent in three (12%). All 22 specimens with detachment lacked detectable junction-associated Laminin-R/RPSA immunoreactivity at the corresponding interface, whereas all three specimens without detachment retained the signal. All 25 preserved perilesional regions showed retained immunoreactivity. The paired absolute difference in the proportion showing loss of immunoreactivity between lesion and perilesional sites was 88.0 percentage points (95% CI, 55.5–97.5; exact McNemar p < 0.0001). These findings demonstrate a consistent spatial correspondence between dermo-epidermal separation and localized loss of detectable Laminin-R/RPSA immunoreactivity. Because the antibody targets RPSA rather than laminin-332, the results do not directly establish laminin-332 damage. Laminin-R/RPSA immunohistochemistry may complement conventional H&E examination, but controlled comparative studies are required to determine specificity and reproducibility.