Introduction:
Chronic histiocytic intervillositis (CHI) is a rare placental chronic inflammatory condition with high recurrence rates in subsequent pregnancies. We report a case of recurrent CHI with severe fetal growth restriction with delivery of a liveborn infant at 36 weeks gestation.
Case Presentation:
A 36yo G4P2 was transferred from another centre at 30weeks’-gestation for management of severe fetal growth restriction (FGR). She had a past medical history of type 1 diabetes mellitus. Her obstetric history included a first trimester miscarriage in 2011, followed in 2012 with an uncomplicated vaginal delivery of a liveborn male infant at 40weeks’ gestation (birthweight 3046g). A subsequent pregnancy in 2020 was complicated by severe early-onset FGR necessitating delivery at 29weeks’ -gestation: the liveborn male infant weighed 495g. Placental histopathology demonstrated CHI.
Due to the history of CHI, she was started on aspirin and hydroxychloroquine. At 25weeks'-gestation, recurrent severe FGR <1st centile was diagnosed. She underwent amniocentesis with a normal chromosomal microarray. Her ALP was significantly elevated (pre-delivery peak of 1672U/L, predominant placental isoform). Serial growth surveillance confirmed fetal biometry <1st centile, with normal liquor volume and doppler studies.
At 36weeks’-gestation, she underwent an emergency caesarean section within the setting of preterm prelabour ruptured membranes, delivering a 1890g female infant. Five days post-partum, the ALP was 721U/L. Placental histopathology revealed increased capillary profiles of the chorionic villi consistent with chorangiosis, increased intervillous fibrin, mild intervillous infiltrate of histiocytes, highlighted by CD68+ immunohistochemistry. There was a minor component of chronic villitis and immunohistochemistry for CD45 highlighted scant lymphocytes. The histopathology of the current placenta when compared to the 2020 pregnancy showed histiocytic infiltrate was less than in the previous placenta, less frequent sheets of cells and smaller aggregates overall. This may relate to the treatment which was initiated.
Discussion:
CHI is a rare chronic inflammatory placental lesion characterized by excessive accumulation of maternal CD68+ histiocytes in the intervillous space. It has high rates of first-trimester miscarriage, severe FGR and stillbirth1. The hypothesised pathogenesis is inappropriate immune response to the semi-allogeneic fetus2. Limited evidence exists to guide treatment. Potential therapies include aspirin, LMWH, prednisolone, hydroxychloroquine and adalimumab3. CHI has a strong recurrence rate of ~80%4. Recognition of this condition through identification of extremely elevated ALP levels and FGR is critical to management of current and subsequent pregnancies. In this case, a less severe disease phenotype may be related to the early commencement of aspirin and hydroxychloroquine.