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Chronic Rhinorrhea
This case features a patient presenting with chronic rhinorrhea, ultimately diagnosed with a meningoencephalocele.
Imaging overview:
Coronal and sagittal non-contrast CT demonstrates an osseous defect at the left fovea ethmoidalis with subjacent expansile fluid and soft tissue attenuation extending into the ethmoid air cells and nasal cavity. Coronal T2 MRI confirms herniation of dysplastic brain parenchyma, CSF, and meninges through the skull base defect, consistent with a meningoencephalocele.
Clinical insight:
Cephaloceles are herniation of intracranial contents through a skull base defect and are named by their contents: a meningocele contains only meninges and CSF, while a meningoencephalocele also contains brain parenchyma. They can be congenital or acquired, with acquired cases resulting from prior trauma, surgery, or raised intracranial pressure. Chronic rhinorrhea in this setting reflects CSF leakage through the defect. Anterior skull base anatomy is a critical component of preoperative sinus CT evaluation, as unrecognized skull base dehiscence carries significant risk of intracranial injury during endoscopic sinus surgery. MRI is complementary to CT for characterizing the herniated contents and confirming the diagnosis.
Case courtesy of Miguel Ibarra, MD, and Benjamin Gray, MD, Indiana University School of Medicine.