Hamish Carmichael¹, Seethalakshmi Viswanathan^1,2

¹Institute of Clinical Pathology and Medical Research, Westmead Hospital, Westmead, NSW, Australia; ²The University of Sydney, Camperdown, NSW, Australia

Chronic histiocytic intervillositis (CHI) is a placental disorder associated with poor perinatal outcomes and recurrent pregnancy loss. It is characterised by the histopathological finding of a significant infiltration of CD68 positive mononuclear cells within the intervillous space, often with accompanying perivillous fibrin deposition¹. It is a rare condition with a prevalence of 0.38% in first trimester pregnancy losses². Its recognition is critically important due to its high recurrence rate and the existence of emerging treatment options for future pregnancies, which need to be managed as high risk³. We describe a case of CHI in a 22 year old primigravida in the setting of a first trimester miscarriage. This case demonstrates the importance of the pathologist being aware of this condition so that it is not missed, since these cases are diagnosed on histopathological examination.
 

1. Bos M, et al. Towards standardized criteria for diagnosing chronic intervillositis of unknown etiology: a systematic review. Placenta. 2018; 61: 80-88. 

2. Simula N, et al. Chronic intervillositis of unknown etiology: prevalence, patterns and reproductive outcomes at a tertiary referral institution. Placenta. 2020; 100: 60-65. 

3. Brady C, et al. Immunomodulatory therapy reduces the severity of placental lesions in chronic histiocytic intervillositis. Front Med. 2021; Oct 18; 8:753220.
 
Originality statement: Dr H. Carmichael conducted this study, abstract, and poster under supervision of Dr S. Viswanathan.