Recurrent tumefactive demyelinating lesions; This literature-non-study case was reported in a literature article and describes the occurrence of TUMEFACTIVE MULTIPLE SCLEROSIS (Recurrent tumefactive demyelinating lesions) in a 72-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis.   LITERATURE REFERENCE:     Concurrent medical conditions included Tumefactive multiple sclerosis (in the right frontoparietal region).  On an unknown date, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced TUMEFACTIVE MULTIPLE SCLEROSIS (Recurrent tumefactive demyelinating lesions) (seriousness criterion medically significant). At the time of the report, TUMEFACTIVE MULTIPLE SCLEROSIS (Recurrent tumefactive demyelinating lesions) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Histology: tumefactive demyelinating lesion in the right frontoparietal region. On an unknown date, Magnetic resonance imaging head: Initial lesion with interval development of new multifocal tumefactive demyelinating lesions.  For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Concomitant and treatment medications were not provided.  The patient initially presented with progressive left hemiparesis and hemisensory deficits due to a pathology-confirmed tumefactive demyelinating lesion in the right frontoparietal region. Symptoms improved with glucocorticoids and plasmapheresis. Five months following initial presentation, the patient developed right visual field deficits and acute encephalopathy. Brain imaging revealed near resolution of the initial lesion with interval development of new multifocal tumefactive demyelinating lesions. The authors concluded that this case highlights several atypical features associated with tumefactive demyelinating disease, including an older age of onset and recurrent, treatment-resistant lesions.  Company comment: This literature-non-study case report concerns a 72-year-old female patient with history of Tumefactive multiple sclerosis in the right frontoparietal region, who experienced serious (medically significant) unexpected event of Recurrent tumefactive multiple sclerosis after receiving the second dose of the mRNA-1273 vaccine, however, temporal relationship is unknown since date of vaccination and start date of the event remained unknown. Reportedly, the patient initially presented with progressive left hemiparesis and hemisensory deficits due to a pathology-confirmed tumefactive demyelinating lesion in the right frontoparietal region. Symptoms improved with glucocorticoids and plasmapheresis. However, five months following initial presentation, the patient developed right visual field deficits and acute encephalopathy. Brain imaging revealed near resolution of the initial lesion with interval development of new multifocal tumefactive demyelinating lesions. As per the authors, this case presented atypical features associated with tumefactive demyelinating disease, including an older age of onset and recurrent, treatment-resistant lesions. Tumefactive multiple sclerosis usually has variable presentations and course, characterized by remissions and flares which can be triggered by various factors in these individuals. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This literature-non-study case report concerns a 72-year-old female patient with history of Tumefactive multiple sclerosis in the right frontoparietal region, who experienced serious (medically significant) unexpected event of Recurrent tumefactive multiple sclerosis after receiving the second dose of the mRNA-1273 vaccine, however, temporal relationship is unknown since date of vaccination and start date of the event remained unknown. Reportedly, the patient initially presented with progressive left hemiparesis and hemisensory deficits due to a pathology-confirmed tumefactive demyelinating lesion in the right frontoparietal region. Symptoms improved with glucocorticoids and plasmapheresis. However, five months following initial presentation, the patient developed right visual field deficits and acute encephalopathy. Brain imaging revealed near resolution of the initial lesion with interval development of new multifocal tumefactive demyelinating lesions. As per the authors, this case presented atypical features associated with tumefactive demyelinating disease, including an older age of onset and recurrent, treatment-resistant lesions. Tumefactive multiple sclerosis usually has variable presentations and course, characterized by remissions and flares which can be triggered by various factors in these individuals. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.