Abstract
BACKGROUND: Perivascular spaces are interstitial fluid-filled regions located deep to the pia mater. They play roles in lymphatic drainage and the central nervous system immunological function. When they enlarge, they are referred to as giant tumefactive perivascular spaces. Often misdiagnosed as cystic neoplasms, they require a high degree of clinical suspicion and key radiological features to be accurately diagnosed. We describe an interesting case in which a man presented with worsening headache, subsequently found on neuroimaging to have this phenomenon. CASE DESCRIPTION: A 32-year-old man with low testosterone presented to the ER for worsening headache, blurred vision, and photophobia. Computed tomography of the brain showed hydrocephalus with follow-up magnetic resonance imaging revealing several enlarged cystic spaces within the brain, concerning for neoplasm. He ultimately left against medical advice before the further evaluation was done. He followed up with a neurosurgeon as an outpatient, where further review showed characteristic features indicative of giant tumefactive perivascular spaces, thus avoiding the need for unnecessary biopsy and potential surgery. CONCLUSION: Often misdiagnosed as cystic neoplasms, giant tumefactive perivascular spaces are benign processes that can have a broad presentation with the most common finding being a headache. Key radiologic features, including smooth margins, isointensity to cerebrospinal fluid, and lack of postcontrast enhancement, are crucial to diagnosis, preventing unnecessary surgery with increased morbidity.