Imaging Features of Juvenile Xanthogranuloma of the Pediatric Head and Neck

BACKGROUND AND PURPOSE: Juvenile xanthogranuloma is a non-Langerhans cell histiocytosis primarily affecting children. The purpose of this study was to characterize the imaging features of histologically confirmed pediatric head and neck juvenile xanthogranuloma. MATERIALS AND METHODS: A retrospective review was performed of medical records and imaging of histologically confirmed head and neck juvenile xanthogranuloma. RESULTS: Ten patients (6 girls, 4 boys)] month to 12 years of age were imaged with ultrasound only (n = 1), CT only (n = 2), CT and ultrasound (n = 1), MR imaging only (n = 3), or MR imaging and CT (n = 3). Masses were solitary in 9 patients and multiple in 1. Solitary masses were located in the external auditory canal,infra-auricular region, infratemporal fossa with intracranial extension, frontal scalp, and subperiosteal space eroding the calvaria and along the dura. One patient with disseminated disease had scalp-, calvarial-, and dural-based masses. Clinical presentation included a mass or alteration in function. On sonography, juvenile xanthogranuloma appeared hypoechoic. On contrast-enhanced CT, masses appeared homogeneous and isoattenuating with muscle and sometimes eroded bone. On MR imaging, compared with the cerebral cortex, the masses appeared hyper- or isointense on TI and hypo- or isointense on T2, had decreased diffusivity, and enhanced homogeneously. Juvenile xanthogranuloma was not included in the differential diagnosis in any case. CONCLUSIONS: Head and neck juvenile xanthogranuloma has varied manifestations. Mild hyperintensity on TI, hypointensity on T2 compared with the cerebral cortex, decreased diffusivity, and homogeneous enhancement are characteristic. Awareness of these features should prompt radiologists to include juvenile xanthogranuloma in the differential diagnosis of pediatric head and neck masses.