Occult congenital syphilis in macerated stillborn fetuses.

Five cases of macerated stillborn fetuses with congenital syphilis were studied. Despite severe maceration with visceral autolysis, spirochetes could be easily detected using Warthin-Starry stains. Clues that led to performing silver stains included the presence of an enlarged liver, spleen, chorioamnionitis, and nucleated red blood cells in villous capillaries. In a patient population where prenatal care is not always obtained, and maternal serologic tests results are not available at the time of delivery, these pathologic clues are very helpful in detecting congenital syphilis in macerated stillborn fetuses where the classic findings of syphilitic infection, including hydrops fetalis and plasma cell infiltrates, may be masked.