Paraneoplastic cerebellar degeneration (PCD) is usually thought to have a subacute progression over several weeks. We report herein incidence and clinical features of hyperacute onset PCD, a vertebrobasilar stroke mimic. We performed a retrospective analysis of all suspected PCD cases referred to the Udine University Hospital between 2009 and 2017. Our center provides the only neuroimmunology laboratory for three provinces of the Friuli-Venezia Giulia region, Italy (983,190 people as of January 1, 2017). Inclusion criteria were (1) abrupt onset of neurological symptoms; (2) initial consideration of a vascular etiology; (3) final diagnosis of "definite PCD." We also carried out a systematic review of the literature in order to identify previous stroke-like PCD cases. Between 2009 and 2017, 24 patients received a final diagnosis of PCD. The age-standardized incidence rate of PCD was 0.22/100,000 person-years. Two cases (8.3%) had a stroke-like onset, with an incidence of 0.02/100,000 person-years. Additionally, 10 previously reported stroke-like PCD cases were identified. Among all cases (n = 12), 67% were female; median age was 51 years (range, 22-69). An associated cancer was discovered in all cases. Brain imaging was normal in most (75%) of the patients. Cerebrospinal fluid (CSF) analysis showed inflammatory alterations in 73% of the cases. Cancer treatment was more effective than immunotherapy in improving the neurological syndrome. Typical patients with hyperacute PCD are middle-aged women with normal brain imaging, inflammatory markers in CSF, and cancer. Surgery of the underlying cancer is probably the best treatment. PCD must be considered in the differential diagnosis of acute-onset ataxia and/or vertigo.
Keywords: Ataxia; Differential diagnosis; Epidemiology; Incidence; Paraneoplastic syndromes; Stroke.