Pathological evaluation of pseudoeschar formation after enzymatic debridement with nexobrid: a case report

• Pseudoeschar may form after Nexobrid enzymatic debridement of burn wounds. • Mechanism and pathology of pseudoeschar formation remain unclear. • We examined pseudoeschar in a flame burn case after enzymatic debridement. • Pseudoeschar consisted mainly of collagen and elastic fibers. • Residual necrotic tissue may be extruded to surface, forming pseudoeschar. Nexobrid, bromelain-based debriding enzyme, is widely used in burn treatment to remove necrotic skin tissue. However, the formation of a necrotic layer, known as “pseudoeschar”, after debridement remains poorly understood. We performed a pathological evaluation of pseudoeschar. We report the case of a man in his 50 s who suffered a flame burn on his right shoulder and upper arm. Pre-soaking with normal saline was performed overnight, followed by enzymatic debridement with Nexobrid 22 h post-injury. Pinpoint bleeding was observed after debridement, and pseudoeschar formation was observed on the 6th day post-injury. A skin biopsy was taken from the burn wound on the 10th day post-injury, followed by surgical treatment. Histopathological evaluation revealed that the pseudoeschar consisted of collagen and elastic fibers. Additionally, inflammatory cells, collagen, and elastic fibers appeared to ascend from the lower dermis to the pseudoeschar, penetrating through the ulcer layer. The pseudoeschar comprised collagen and elastic fibers. Its formation may involve the transepithelial elimination of degenerated dermal components, a mechanism similar to that observed in perforating dermatoses. Further research is needed to elucidate the underlying mechanisms and clinical significance of pseudoeschar formation.