Hyrtl's fissure - a rare congenital temporal bone anomaly

Hyrtl's fissure is a rare congenital temporal bone anomaly that may cause cerebrospinal fluid (CSF) otorrhea and recurrent bacterial meningitis in children. We report a case of a 9-year-old girl who presented with headache, fever, neck stiffness, photophobia, and right ear pain. Cerebrospinal fluid analysis confirmed bacterial meningitis caused by Streptococcus pneumoniae. During planned tympanostomy, continuous drainage of clear fluid was observed, and bedside glucose testing suggested CSF leakage. Imaging, including high-resolution computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI), demonstrated a fistulous tract from the internal auditory canal to the jugular bulb, consistent with a patent Hyrtl's fissure. This case highlights the importance of recognizing congenital temporal bone defects in children with recurrent meningitis or atypical middle ear effusions. Hyrtl's fissure-associated CSF leaks are extremely rare, with few cases reported in the literature. Prompt diagnosis and surgical management are essential to prevent life-threatening infections and preserve hearing, even in cases with normal inner ear anatomy.