Chronic Histiocytic Intervillositis – Clinical, Biochemical and Radiological Associations [30F]

INTRODUCTION: To determine the clinical, biochemical and radiological features associated with a histopathologic diagnosis of chronic histiocytic intervillositis (CHI), and propose surveillance strategies for pregnancies at risk for this condition. METHODS: A retrospective chart review was conducted to identify cases with a diagnosis of CHI between 2001 and 2014. Adverse pregnancy outcomes included pregnancy loss, preterm birth, small for gestational age (SGA) and preeclampsia. Maternal tests included serum alkaline phosphatase (ALKP) and prenatal screening bioanalytes. Mid-trimester placental ultrasound reported placental dimensions, echotexture, echogenic cystic lesions, infarcts and uterine artery pulsatility indices. Late-trimester ultrasound reported umbilical artery Dopplers and amniotic fluid volume. Outcomes were described as proportions. RESULTS: Of the 261 cases of intervillositis identified, 33 were cases of CHI. Fetal demise was noted in 13/33 (39.4%) of which 11 (35.5%) were stillbirths. Of the 18 live births, 16 (88.9%) delivered prematurely; 6 of these (33.3%) before 34 weeks and 12 (66.7%) required neonatal unit admission. All babies born after 22 weeks were SGA, with 15/23 (65.2%) under the 3rd centile. Preeclampsia complicated 9/33 (27.3%) of pregnancies. 12/16 (75.0%) had at least one abnormal prenatal screening bioanalyte and 6/19 (31.57%) ALKP levels 2.5 times above normal. 15/20 (75.0%) had at least one abnormal mid-trimester placental ultrasound marker. CONCLUSION: CHI is associated with a cluster of clinical, biochemical or radiological findings. Given the high recurrence rate and no available treatment, individualized care plans based on a combination of clinical, biochemical and radiological tests have been proposed to improve outcomes in subsequent pregnancies.