<i>Mycobacterium riyadhense</i> Infection Presenting as a Central Nervous System Mass: A Case Report.

Mycobacterium riyadhense (M. riyadhense) is a slow-growing nontuberculous mycobacterium that is increasingly being recognized as a cause of pulmonary and extrapulmonary disease, primarily in Saudi Arabia. Here, we report a case of M. riyadhense with an unusual presentation as a central nervous system mass, with an initial diagnosis of neurosarcoidosis and notable improvement with the use of steroids and rituximab prior to establishing the final diagnosis.