Anti-Yo related pure sensory ganglionopathy: a rare paraneoplastic entity

Sensory ganglionopathy (SG) results from involvement of the dorsal root ganglia. Clinically, it presents with asymmetric, usually non-length-dependent, sensory symptoms, sensory ataxia and reduced or absent tendon reflexes. Electrophysiologically, there is an absence or asymmetry of sensory nerve action potentials (SNAPs). Etiologies include genetic, autoimmune, and paraneoplastic causes.

Case report and review of the literature.

We report a case of pure sensory ganglionopathy (SG) without cerebellar involvement associated with anti-Yo antibodies. A 78-year-old woman presented with a two-year history of progressive limb paresthesias. Electrophysiological studies demonstrated a non-length-dependent asymmetric sensory neuropathy with normal motor conduction studies, pointing toward SG, and serological testing was positive for anti-Yo antibodies. Initial FDG-PET imaging was unremarkable; however, repeat imaging identified two hypermetabolic foci in the right breast. The patient subsequently underwent a partial mastectomy, and histopathological analysis confirmed infiltrating papillary, hormone receptor-positive carcinoma. Following oncological treatment, the patient remained clinically and neurophysiologically stable, with mild subjective improvement in numbness. Pure SG associated with anti-Yo antibodies is exceedingly rare, with only two previously reported cases—one linked to breast cancer and another to ovarian cancer.

Diagnosing SG is challenging, and the presence of anti-Yo antibodies together with electrophysiological findings should raise suspicion, even in the absence of cerebellar involvement. Thorough evaluation and close oncological follow-up are essential.