Chronic histiocytic intervillositis of unknown etiology: clinical features in a consecutive series of 69 cases.

INTRODUCTION Chronic histiocytic intervillositis of unknown etiology (CIUE) is a rare placental inflammatory disease, associated with severe obstetric complications. Its pathophysiologic mechanism remains to be elucidated. AIM To establish anatomical-clinical correlations to improve our understanding of CIUE pathophysiology. MATERIAL AND METHODS Retrospective study of all cases of CIUE occurring during a 9-year period in a university tertiary hospital center. RESULTS CIUE was diagnosed in 69 pregnancies in 50 different women, after early spontaneous abortions (30.4%), late spontaneous abortions (13.0%), in utero deaths (26.1%), and live births (30.4%). Of 39 fetuses surviving to at least 22 weeks, 24 had severe intrauterine growth restriction (61.5%) and 18 died in utero (46.2%). Twelve in utero deaths occurred before 32 weeks of gestation (66.7%). Substantially elevated alkaline phosphatase levels (>600 IU/L) were observed in 55.6% of cases. Microscopic examination of placentas showed that both spontaneous early abortions and intrauterine growth restriction were significantly associated with more intense fibrin deposits. CONCLUSION A diagnosis of CIUE must be considered in cases of severe obstetric complications. We hypothesize that the elevated alkaline phosphatases (ALP) observed during the pregnancy demonstrate the presence of syncytiotrophoblastic lesions due to histiocytosis in the intervillous space, before fibrin deposits cover them.