Tumor Expression of Cerebellar Degeneration-Related Protein 2-Like in Rapidly Progressive Cerebellar Syndrome Associated With Oropharyngeal Squamous Cell Carcinoma.

We report a 68-year-old man with anti-Yo/Purkinje cytoplasmic autoantibody type 1 (PCA-1)-associated rapidly progressive cerebellar syndrome in the underlying oropharyngeal squamous cell carcinoma (SCC). The patient developed subacute cerebellar ataxia, and brain MRI demonstrated progressive cerebellar atrophy. Anti-Yo/PCA-1 antibodies were detected by immunoblotting, and IgG reactivity against cerebellar degeneration-related protein 2 (CDR2) and 2-like (CDR2L) was identified using a research-use multiplex autoantibody array assay. Immunohistochemical staining of the oropharyngeal SCC showed immunoreactivity with an anti-CDR2L antibody in tumor cells. Although anti-Yo/PCA-1-associated rapidly progressive cerebellar syndrome has rarely been reported in patients with SCC, tumor expression of CDR2L has not been demonstrated in such cases. This case supports the diagnostic value of examining tumor CDR2L expression in anti-Yo/PCA-1-associated rapidly progressive cerebellar syndrome with non-breast/non-gynecologic malignancies, especially SCC.