Transtentorial herniation from tumefactive multiple sclerosis mimicking primary brain tumor

Abstract

Background:Multiple sclerosis (MS) is a chronic central nervous system inflammatory demyelinating disease characterized by multiple lesions disseminated in time and space. The lesions often have characteristic imaging findings on magnetic resonance (MR) imaging and cerebrospinal fluid findings that lead to their diagnosis. At times, these lesions may resemble tumors due to their large size (>2 cm), significant vasogenic edema, and ring-enhancing MR imaging findings. Such lesions are described as tumefactive demyelinating lesions or tumefactive MS, and they are generally seen in aggressive forms of MS associated with rapid progression.Case Description:We report an uncommon but clinically significant case of transtentorial brain herniation secondary to malignant cerebral edema from tumefactive MS in a 50-year-old woman. After the initial diagnosis of MS, the patient continued to have progression of her white matter lesions suggesting evolution of her MS despite treatment with intravenous (IV) steroids, IV immunoglobulin, and plasmapheresis. She was admitted to the hospital with a new, large, ring-enhancing lesion that displayed significant mass effect from vasogenic edema and progressed, necessitating a decompressive hemicraniectomy.Conclusion:Tumefactive MS presents a unique pathology that can often mimic primary brain tumors. Although these lesions affect white matter and infrequently cause a significant amount of mass effect, they can act like a tumor, causing edema that generates sufficient intracranial pressure to cause transtentorial herniation.

Tumefactive Demyelination in MOG Ab–Associated Disease, Multiple Sclerosis, and AQP-4-IgG–Positive Neuromyelitis Optica Spectrum Disorder

“…[4][5][6] They can be accompanied by severe clinical manifestations (with potential for intensive care unit admission) and often represent a diagnostic challenge for neurologists, especially when encountered in isolation as the initial manifestation of the disease. 7,8 These lesions have been described in up to 2% of patients with MS, 9 3% of patients with AQP4+NMOSD, 10 and during MOGAD attacks. 5,11 However, the frequency of this manifestation in MOGAD is still unknown because no studies have systematically evaluated tumefactive demyelination in this disease.…”

“…evaluated images in an anonymous fashion for consensus. The definition and pictorial explanation of features evaluated are reported in Figure 1 and included the presence of the following: (1) T2-hypointense rim on T2-weighted image, 22 (2) T1-hypointensity on T1-weighted image, 4 (3) Baló-like appearance, 23 (4) cystic component, 24 (5) poorly demarcated borders (i.e., fluffy appearance), 25 (6) restricted diffusion within the lesion, 26 (7) arc/ring of peripheral restricted diffusion, 12 (8) enhancement on postcontrast T1weighted images, (9) pattern of enhancement on postcontrast T1-weighted images including ring (closed if complete; otherwise, open) 22 and cloud-like, 27 and (10) mass effect (i.e., if the lesion exerted a secondary effect on adjacent structures such as sulci, ventricles, or midline).…”

“…4-6 They can be accompanied by severe clinical manifestations (with potential for intensive care unit admission) and often represent a diagnostic challenge for neurologists, especially when encountered in isolation as the initial manifestation of the disease. 7,8…”