Vernix caseosa peritonitis presenting post partum as acute cholecystitis

Vernix caseosa, the "cheese-like" white cutaneous material covering the skin of the newborn, consists of an admixture of sebaceous glandular secretions, lanugo hair and desquamated squamous cells. These squamous cells are derived from fetal periderm. Normal amniotic fluid consequently contains numerous squamous cells.14 During elective cesarean section, the integrity of the amnion is necessarily disrupted, and its contents may enter the peritoneal cavity.1,4 The amount of such peritoneal contamination during the course of cesarean section is usually not recorded. The onset of peritonitis due to vernix caseosa occurring after uncomplicated cesarean section has been attributed to incomplete peritoneal lavage of spilled amniotic fluid.10 However, both Davis and associates10 and Schwartz and colleagues4 have reported that peritonitis due to vernix caseosa can be initiated by antenatal or intrapartum leakage of amniotic fluid. Suggested mechanisms include uterine-tubal reflux and unrecognized uterine perforation. Although the exact cause of the subsequent development of peritonitis is not known,12 a number of theories have been suggested. Both meconium and keratinized squamous cells have demonstrated the capacity to induce a brisk inflammatory response, collectively or individually, most probably by mechanical irritation:11 the former in the setting of neonatal meconium peritonitis secondary to intestinal perforation and the latter in the context of ruptured keratinous cysts, dermoid cysts and keratinizing neoplasms. Interestingly, meconium is composed largely of swallowed amniotic fluid (which contains anucleate squamous cells and lanugo hair derived from vernix caseosa).7 Furthermore, it is recognized that direct spillage of meconium into the peritoneal cavity can incite a granulomatous peritonitis.2 Clinical diagnosis of peritonitis due to vernix caseosa should be considered in all patients presenting with an acute abdomen after elective or emergency cesarean section. Although the other causes of peritonitis such as appendicitis, cholecystitis and a perforated viscus are still more common than vernix caseosa peritonitis, surgeons should be aware of this rare but interesting condition.