A pediatric case of central skull base osteomyelitis caused by Streptococcus milleri group infection and mimicking malignancy.

Central skull base osteomyelitis (CSBO) that has expanded to the middle cranial fossa is a rare complication of nasopharyngeal infection in children. Diagnosing CSBO is challenging in children, because specific symptoms are lacking and imaging findings can mimic skull base malignancy. We report on a 3-year-old girl who complained of pyrexia, headache, and vomiting and in whom a mass around the clivus was detected with magnetic resonance imaging. The patient received a diagnosis of CSBO based on characteristic imaging findings and the detection of a Streptococcus milleri group (SMG) in blood cultures. Clinical symptoms and abnormal imaging findings, including a mass lesion, were improved by prompt antibiotic treatment. The present patient had paranasal sinusitis with bacteremia of SMG, leading to the speculation of hematogeneous dissemination of SMG from the paranasal sinus. Awareness of CSBO, its early diagnosis, and aggressive management are required because CSBO is associated with high morbidity due to a life-threating infection involving multiple cranial nerves.