Elsberg Syndrome: A Case Report of a Novel Radiographic Presentation.

Elsberg syndrome (ES) presents with bowel and bladder dysfunction, resembling cauda equina syndrome, and is classified as a clinicoradiographic syndrome most commonly associated with HSV-2 reactivation. Most cases reveal smooth and continuous nerve enhancement on imaging. We present a unique case of ES that presented as several nodular, ring enhancing soft tissue masses along the cauda equina. An 81-year-old woman presented with several weeks of sacral sensory impairment. MRI of the lumbar spine at presentation showed several nodular, ring enhancing soft tissue masses within the thecal sac along the cauda equina, concerning for leptomeningeal carcinomatosis from an unknown primary source. Cerebrospinal fluid (CSF) analysis was notable for lymphocyte predominant pleocytosis and protein elevation, which was nonspecific but suggestive of leptomeningeal carcinomatosis. CSF rapid meningitis panel was positive for HSV2 which was confirmed on HSV2 PCR. The patient was briefly on on acyclovir and was stopped due to lack of meningioencephalitis symptoms. Malignancy workup with cytological analysis and systemic imaging were negative. Given the absence of malignancy and positive HSV2 PCR, the patient was diagnosed with HSV-2 sacral radiculitis and subsequently treated with a full course of intravenous acyclovir with gradual clinical and radiographic improvement. Ring-enhancing lesions along the cauda equina are most suggestive of LC. Our case highlights an as of yet unreported presentation of ES which may be valuable for neurologists to be aware of as to avoid any potential diagnostic dilemma, minimize unnecessary and costly testing, and not delay effective treatment.