Objective: Describe the embryologic origin and developmental anatomy of the torcular pathology. Identify the key MRI and MR venography characteristics of torcular pseudomass that distinguish it from dural venous sinus thrombosis and other posterior fossa lesions. Recognize the typical clinical scenarios in which torcular pseudomass is discovered and understand its benign, self-limiting natural history. Learning Points: Torcular pseudomass is a benign, self-limiting developmental variant in infants, not true mass. Appears midline, as a non-enhancing, extra-axial soft-tissue prominence posterior to the torcular Herophili on MRI Differential diagnoses include dural venous sinus thrombosis, dermoid cyst, and neoplasm. No enhancement or venous obstruction on MRV distinguishes it from thrombosis. Follow-up is rarely required unless associated abnormalities are suspected. Recognition of this entity prevents unnecessary imagination or surgical intervention. Most cases resolve spontaneously by 12–18 months of age. Discussion: Torcular pseudomass is a non-pathologic developmental variant located posterior to the torcular Herophili, the confluence of dural venous sinuses. It represents persistent mesenchymal tissue that fails to fully regress after birth. While uncommon, it is increasingly recognized with the wider use of MRI in infants. This benign entity typically appears between 2–6 months of age and resolves spontaneously within the first year of life. The overall prevalence is unknown, but literature shows on MRI series estimate Torcular pseudomass is found an incidental in up to 1–2% of pediatric neuroimaging studies. Awareness of this variant is essential, as it can be mistaken for dural venous sinus thrombosis, dermoid cyst, or posterior fossa tumor. Misdiagnosis may lead to unnecessary interventions such as anticoagulation or biopsy. Read More

Meeting name: SPR 2026 Annual Meeting , 2026

Authors: Gardner Kyle, Kuwabara Michael

Keywords: Congenital, MRI Brain

Balamuthia mandrillaris is an amoeba that causes an uncommon but deadly encephalitis, referred to as granulomatous amoebic encephalitis (GAE). The highest incidence reported worldwide has occurred in America, and within the United States, it has been highest in the Southwest affecting predominantly children and young men of Hispanic ethnicity. Clinical presentation of GAE includes fever, headache, nausea, vomiting, lethargy, irritability, stiff neck, hallucinations, photophobia, and seizures. Our patient was a Hispanic male child living in Arizona. The patient presented at 3 years of age for severe encephalitis. Symptoms included difficulty with balance, gait, and sitting up and seizure-like activity. Initial CT showed an area of decreased density consistent with edema in the left frontoparietal lobe. Rapid progression was seen on further imaging over the length of the patient’s hospital stay revealing diffusion restriction, necrosis/blood products, edema, and hemorrhage. The patient expired from tonsillar herniation 22 days after the onset of initial symptoms and 4 days after admission to our institution. While there are multiple biochemical techniques that can test for B. mandrillaris, they are rarely employed for multiple reasons stemming from the rare occurrence of this infection. Balamuthia mandrillaris can cause a lethal brain infection. Because of the fatal nature of this infection, we propose 1) testing should be considered if a patient presents with progressing encephalitis on imaging and other pathogenic etiologies are ruled out and 2) the threshold to treat empirically should be low due to the fatal nature of the infection. Read More

Meeting name: SPR 2024 Annual Meeting & Postgraduate Course , 2024

Authors: Szymanski Kathryn, Pfeifer Cory, Friedman Neil, Kuwabara Michael

Keywords: amoeba, Balamuthia mandrillaris, brain infection