CSF or middle ear effusion? Diagnostical dilemmas in a patient with temporal bone meningioma: A case report

Introduction: Cerebrospinal fluid (CSF) fistulas are a rare phenomenon, that can lead to life-threatening complications if left untreated. Presenting as rhinorrhea or otorrhea, they can be difficult to diagnose due to admixture of other bodily fluids. Typically, CSF fistulas develop after trauma, but in rare instances, they can be diagnosed in patients with a neoplastic lesion. Objective: To discuss several steps in diagnosing CSF fistulas. Patient: A fifty-year-old female with an intra-osseous temporal bone meningioma. Interventions: For diagnosing CSF admixture in fluids, two tests are looked into: beta-2 transferrin (ß2T) and beta-trace protein (ßTP) testing. Conclusion: Testing for ßTP is a highly sensitive, quick and non-invasive method to assess CSF admixture in middle ear effusion. Because of its lower cost, faster results and easy sample collection, ßTP testing has in our clinic replaced ß2T testing. The current case illustrates a rare etiology of a CSF fistula, where ß2T testing presumably showed false-negative results and ßTP testing showed true-positive results.