A paraneoplastic syndrome manifesting as subacute cerebellar degeneration is associated with anti-Yo antibodies (anti-PCA-1). The target antigen CDR2 is expressed by the tumor and cross-reacts with Purkinje cell antigens. Which primary malignancy most characteristically produces this paraneoplastic syndrome?

• A Breast or ovarian carcinoma ✓
• B Small cell lung carcinoma
• C Thymoma
• D Testicular seminoma

Explanation

Anti-Yo antibodies (anti-Purkinje cell antibody type 1, PCA-1) are most frequently associated with breast and ovarian carcinomas, which ectopically express the CDR2 (cerebellar degeneration-related protein 2) antigen. The antibody-mediated or T-cell-mediated destruction of Purkinje cells leads to irreversible subacute cerebellar degeneration with truncal and limb ataxia. Small cell lung carcinoma is associated with anti-Hu (sensory neuropathy) and anti-VGCC (Lambert-Eaton). Thymoma is linked to myasthenia gravis.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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