Massive subchorionic thrombohematoma (Breus' mole): An exceedingly rare placental disorder-Case series and systematic...

Breus' mole, or massive subchorionic thrombohematoma (MST), is an exceedingly rare placental condition associated with adverse pregnancy outcomes. We aim to describe the clinical, ultrasonographic, and histopathological features of newly diagnosed MST cases and review those previously reported.

We conducted a retrospective observational study of MST cases diagnosed between 2016 and 2024 in two Spanish referral hospitals for high-risk pregnancies. A systematic review of the literature was also performed.

We identified 18 new MST cases. The mean maternal age was 32.5 years. Maternal heart disease was present in 42 % of cases. The mean gestational age at delivery was 35.1 weeks; 72.2 % of neonates were born preterm. Fetal growth restriction (FGR) was present in 55.2 %. No intrauterine fetal deaths occurred. Obstetric or maternal complications appeared in 77.1 % of pregnancies. The most common ultrasound findings included placental thickening (11.7 %), fetal surface hematomas (11.7 %), lacunar appearance (11.7 %), and amnion detachment (11.7 %). Doppler assessments were normal in 76.4 %. Placentomegaly or hypoplasia were observed in 11.6 % and 22.3 %, respectively. Histology showed yellowish, indurated areas on the fetal surface, affecting 30-100 % of the surface and measuring 1-2.3 cm in depth. Serous cysts were found in 11.2 %. Circumvallate/circummarginate insertion occurred in 22.3 %, and marginal/velamentous cord insertion in 33.4 %. Maternal vascular malperfusion pattern was present in 72.3 %. Seventy-four MST cases have been previously reported.

MST should be considered in the differential diagnosis of FGR, especially when ultrasound findings show placental thikenning and hematoma in the chorionic plate in mothers with heart disease. Histological confirmation and close ultrasound follow-up are key for appropriate management.