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Paraneoplastic Cerebellar Degeneration — RACP Adult Medicine MCQ

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ModerateNeurologyParaneoplastic Cerebellar DegenerationRACP Adult Medicine

A 60-year-old woman with small cell lung carcinoma presents with progressive cerebellar ataxia, dysarthria, and nystagmus over 6 weeks. MRI brain is initially normal. CSF shows lymphocytic pleocytosis with elevated protein. Anti-Yo (PCA-1) antibodies are positive in serum. What is the most likely paraneoplastic syndrome?

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Correct answer: B — Paraneoplastic cerebellar degeneration

Subacute cerebellar ataxia with positive anti-Yo antibodies in the context of malignancy is paraneoplastic cerebellar degeneration. Anti-Yo is most commonly associated with ovarian and breast cancer. Anti-Hu may also cause PCD in SCLC. Neurological symptoms often precede cancer diagnosis. Treatment of the underlying malignancy may stabilise but rarely reverses the neurological deficit.

Reference: PNS-Care 2024 Diagnostic Criteria; eTG Neurology 2024