🔷Notice, lymphoma in this case is producing the “waterfall” or “cascade” sign. Neuroradiologists know that most signs are not as specific as the literature makes them seem. It is best to understand the mechanism of the sign rather than to blindly associate it with a disease. The mesodiencephalic junction (location of the waterfall sign) is a convergence of densely packed white matter tracts, perforating small vessels & periependymal AQP4-rich astrocytocytes, thus ANY process causing edema, perivascular inflammation, or neoplastic infiltration in this location can cause the waterfall sign. For more reading 📖 pubmed.ncbi.nlm.nih.gov/4121…

⭐️ Answer: Lymphoma, biopsy proven 🔷Lymphoma can occasionally present with a lymphomatosis cerebri pattern which has significant imaging overlap with inflammatory disease rather than a more typical defined mass. These cases should first be worked up for inflammatory disease. If unrevealing or not responding appropriately to treatment then lymphoma should be considered. 🔷In this particular case, uveitis + lack of response to steroids & IVIG, and unrevealing work up now bring lymphoma to the top of the diagnostic list 💡 Uveitis not responding to treatment is a big red flag 🚩 especially in older patients with posterior involvement. This is suspicious for lymphoma and often prompts diagnostic vitrectomy

⭐️ What is the most likely diagnosis in this 50 y/o F who initially presented with uveitis which did not respond to steroids? Over the course of months, she progressively declined and eventually developed encephalopathy. 🔷No significant PMH 🔷CT chest, abdomen and pelvis unremarkable 🔷No significant response to steroids or IVIG 🔷Pathergy testing and HLA-B51 negative 🔷Serum ACE & IL2-R negative #futureradres #MedEd #radres #neurosurgery #ENT #Ophthalmology #Neurology @RadiologyACR @Radiopaedia

⭐️Answer: “Bloomy rind sign” of leptomeningeal carcinomatosis in EGFR mutated primary lung adenocarcinoma 🔷Rare imaging manifestation of leptomeningeal carcinomatosis with all reported cases occurring exclusively in lung adenocarcinoma (most EGFR mutated) 🔷The etiology of the sign is unclear, with proposed theories including tumor infiltration, microinfarction, or effects from cytotoxic edema 🔷IMAGING: ▶️T2/FLAIR signal coating the surface of the pons with diffusion restriction but NO enhancement