Atypical presentations of intracranial dysgerminoma mimicking central nervous system inflammatory or demyelinating disease

OBJECTIVES: The aim of this study is to report a case series of atypical presentations of intracranial dysgerminoma in which the diagnosis was delayed due to clinical and radiographic findings initially suggestive of CNS inflammatory or demyelinating diseases, such as MS. METHODS: This study is a case series detailing the history, clinical presentations, radiographic and laboratory results, and management of three patients with biopsy-proven intracranial dysgerminoma. RESULTS: All three patients demonstrated hyperintense lesions on MRI that were more suggestive of demyelinating or inflammatory diseases, including lesions involving the midbrain and corpus callosum. All three patients were serum positive for oligoclonal bands and negative for both AFP and beta-hCG (these two markers are commonly seen in dysgerminoma cases). One case involved a steroid-responsive tumor whereas the other two cases either did not respond to steroids or steroids were withheld due to uncertainty of etiology. Following biopsy, all three results were consistent with dysgerminoma. CONCLUSION: Clinicians should be aware that dysgerminoma may mimic the clinical and radiographic presentations of demyelinating diseases such as MS. These lesions can cause acute visual loss or diplopia, have MRI and CSF findings that might mimic MS, and have been shown to respond to steroids. Atypical clinical (e.g., headache, dorsal midbrain syndrome, bilateral optic neuropathy) or atypical radiographic features (e.g., mass effect, hydrocephalus) should prompt consideration for repeat imaging and possible biopsy even if serum or CSF tumor markers (beta-hCG and AFP) are negative for dysgerminoma.