Conclusion
In this report, we describe the histopathologic appearance of resorbable collagen membranes. The majority of cases were from curettage specimens of persistent radiolucencies within bone. This material differs from endogenous collagen in its organization and morphology but is identical in its refractility and positive staining with the Masson trichrome stain. Although resorbable collagen membrane is supposed to be fairly rapidly resorbable, this material sometimes persists within wound sites without any obvious foreign body reaction.