Purpose or Case Report: Kaposiform hemangioendotheliomas (KHE) are rare, locally aggressive vascular neoplasms. KHE most commonly arise from the extremities and less frequently the trunk and head and neck regions. Kasabach-Merritt phenomenon complicates 70% of cases. Three cases of KHE underwent prenatal evaluation and postnatal management at our center. We report the imaging findings that may allow for improved prenatal diagnosis.

Case 1: 31-year-old G4P2 evaluated for cervicofacial mass at 24 weeks 5 days. Fetal ultrasound demonstrated a large, infiltrative, predominately solid, mildly heterogeneous mass with a volume of 62 mL. No calcifications or lesion hypervascularity were present. Same day MRI confirmed an infiltrative, predominately solid mass with mild heterogenous T2 signal and no internal flow voids. Repeat MRI at 34 weeks 5 days revealed increased lesion heterogeneity and internal flow voids. US at 36 weeks 3 days demonstrated a volume of 525 mL and lesion hypervascularity. Delivery was at 36 weeks 5 days by EXIT procedure. Kasabach-Merritt phenomenon developed, and postnatal biopsy was consistent with KHE.

Case 2: 35-year-old G2P1 evaluated for cervical mass at 40 weeks 4 days. Fetal ultrasound demonstrated a large, infiltrative predominately solid, mildly heterogeneous mass with a volume of 180 mL. Calcifications and hypervascularity were present. Fetal MRI was not performed. Delivery the next day was by cesarean section. Kasabach-Merritt phenomenon developed. Postnatal biopsy was consistent with KHE.

Case 3: 30-year-old G1P0 evaluated for cervical mass at 38 weeks 1 day. Fetal ultrasound demonstrated a large, predominately solid, heterogeneous mass with a volume of 242 mL. Calcifications and hypervascularity were present. Same day fetal MRI confirmed an infiltrative, predominately solid mass with heterogeneous T2 signal and internal flow voids. Delivery was at 38 weeks 3 days by cesarean section. Kasabach-Merritt phenomenon developed, and postnatal MRI and clinical findings were consistent with KHE.
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Conclusions: An infiltrative, predominately solid mass was the prenatal imaging appearance of all three KHE cases. Hypervascularity was present in third trimester ultrasounds in all cases and internal flow voids were present in the two cases with third trimester MRI. Although less common than cervical lymphatic malformations and teratomas, KHE should be considered in the differential of large, infiltrative, predominately solid and hypervascular cervical masses.