Significance of perivillous fibrin/oid deposition in uterine evacuation specimens

A small proportion of miscarriage specimens obtained by uterine evacuation exhibit increased perivillous fibrin/oid deposition (PVFD). To understand the significance of this finding, the authors reviewed cases from 5/20/02 to 11/10/04 in which surgical pathologists recognized this finding and documented it in their reports. Of 55 cases initially collected, 29 contained at least 30 villi on the slide with at least 50% of villi showing adherent fibrin/oid, and showed no molar change or extensive coagulative necrosis. Review of these 29 cases identified 2 patterns of fibrin/oid deposition: nodular (8 cases) and diffuse (21 cases). A maternal and gestational age-matched control group was collected (21 cases). The diffuse pattern of PVFD encased villi and had tinctorial characteristics of fibrin. Its pattern is similar to that seen in maternal floor infarction and massive perivillous fibrin deposition. The nodular pattern is an exaggerated form of the nodular deposition of matrix-type fibrinoid seen in normal placentas. Comparison of the 3 groups identified a longer duration of vaginal bleeding before uterine evacuation in the diffuse pattern (P=0.001). One patient had a history of 8 miscarriages, 2 of which were represented in this study. All other obstetrical factors studied showed no significant difference between the 3 groups. Thus, diffuse PVFD in miscarriage specimens is associated with prolonged vaginal bleeding and not with maternal thrombophilia or autoimmune disease. Rarely, a patient showing this pattern may have a history of repeated miscarriages.