Primary central nervous system tumors in patients with multiple sclerosis.

Background: Multiple sclerosis (MS) is a chronic neuroinflammatory disorder that can present with clinical and radiological features indistinguishable from a central nervous system (CNS) tumor. Previous studies suggest that whilepatients with MS have a reduced overall risk of cancer, they may have an increased risk of developing CNS malignancies.

Methods: In this cross-sectional observational study, we investigated the prevalence of CNS tumors in patients with MS using data from the Isfahan MS clinic registry between 2020 and 2023 who had been diagnosed with primary CNS tumors following their diagnosis of MS.

Results: Among the 2,280 registered patients, 36 individuals were diagnosed with CNS tumors, yielding a prevalence of 1.58%. The distribution of primary CNS tumors among these patients was as follows: 41.7% had pituitary adenomas, 30.6% had meningiomas, 13.9% had primary CNS lymphoma, 5.6% had acoustic neuroma, and the remaining cases included epidermoid cysts (2.8%), neurofibromas (2.8%), and glioblastoma multiforme (2.8%). The mean age at tumor diagnosis was approximately 45 years, while the mean age at MS diagnosis among those who subsequently developed a CNS tumor was 31.5 years.

Conclusion: The overall prevalence of primary CNS tumors in our MS population was 1.58%. Meningiomas and pituitary adenomas were the most common types of CNS tumors observed in these patients. Given potential symptom overlap, new or unusual symptoms not typical of MS should be closely monitored or assessed for possible CNS malignancies.