Tumefactive multiple sclerosis (TMS): A case series of this challenging variant of MS

Tumefactive MS is a rare variant of multiple sclerosis that poses a diagnostic and a therapeutic challenge due to its close resemblance to central nervous neoplasms on MRI. TMS is defined as acute large >2 cm, tumour like demyelinating lesion in the CNS that may occur with surrounding edema, mass effect and ring enhancement. Some of the known mimickers are CNS lymphoma, metastasis, primary brain tumour such as glioblastoma, brain abscesses. The prevalence of TMS is estimated to be 1-3/1000 cases. There are also reported cases of drug induced TMS cases especially with fingolimod and natalizumab therapy. We report the occurrence of tumefactive MS at our institution.

We retrospectively reviewed the chart of the patients with multiple sclerosis including initial visits, hospitalizations, clinic follow up notes and collected data on demographic, ethnicity, presenting signs and symptoms, imaging modalities, cerebrospinal fluid analysis results, disease progression. After reviewing the charts, we isolated the patients with tumefactive multiple sclerosis from the group and summarized the cases. Four of these patients were managed with Glatiramer acetate, 2 on dimethyl fumarate and 1 on beta interferon with 0-2 clinical flare ups on subsequent years.

Out of 323 patients reviewed with multiple sclerosis or possible multiple sclerosis, 7 carried a diagnosis of tumefactive MS. The age range of these patients were 19 to 62 years old with 4 females and 3 males. Five patients were Caucasian and 2 were Hispanic. Out of seven patients, 6 were newly diagnosed MS following biopsy of the lesion. The histological findings in 3 patients who underwent biopsy demonstrated include reactive gliosis and inflammatory cells predominantly macrophages and lymphocytes while 1 patient showed hypercellular brain tissue with perineuronal satellosis.

Tumefactive MS remains a challenging disease to diagnosis and often times requires a biopsy for definitive diagnosis or to exclude neoplasms, other inflammatory conditions such as neurosarcoidosis. The demographic of the patients in this case series is no different than patients with relapsing remitting multiple sclerosis (RRMS). However, based on our experience, the patients with TMS do respond to disease modifying agents such as Glatiramer acetate and Dimethyl fumarate with similar progression as of RRMS.