Calcified choroid plexus papilloma of the temporal horn presenting with seizures in an adult without hydrocephalus: An illustrative case

Background: Choroid plexus papillomas (CPPs) are rare, benign tumors that typically occur in pediatric patients and result in hydrocephalus. Presentations in an adult featuring seizures, particularly focal impaired awareness seizures, occur infrequently, especially in the absence of hydrocephalus. Case Description: A 50-year-old female exhibited episodes of temporary unresponsiveness characteristic of a focal impaired awareness seizure. Imaging identified a calcified mesial temporal lesion; electroencephalogram revealed epileptiform discharges. Surgical pathology confirmed the presence of CPP. The patient began treatment with levetiracetam and later underwent surgical removal of the tumor. Postoperatively, the patient experienced no seizures and exhibited no neurological deficits. Conclusion: While CPPs usually cause hydrocephalus, this case had no ventricular enlargement on imaging. Instead, a calcified CPP diagnostically mimicked a cavernoma by presenting solely with seizures and a calcified intraventricular temporal-horn mass in a 50-year-old adult; typically, CPPs present in the fourth ventricle rather than the temporal horn, whereas cavernomas regularly present in the temporal lobe with a classically “popcorn-like” appearance. Thus, CPPs can cause focal seizures via local cortical irritation that is calcified, similarly to a cavernoma; CPPs can also present in a middle-aged adult rather than a pediatric patient and lack the most common diagnostic sign of hydrocephalus. The cumulative rarity of a CPP that lacks hydrocephalus, causes seizures, contains calcifications, and manifests later in life makes for an incredibly atypical and unique case of CPP. Without pathology, the given symptoms and imaging were more suggestive of a cavernous malformation rather than a CPP, highlighting the importance of biopsy for an accurate diagnosis; early surgical resection is crucial and may be curative.