Anti-Hu paraneoplastic syndrome with gastrointestinal dysmotility associated with nasopharyngeal squamous cell carcinoma and small bowel adenocarcinoma.

Anti-Hu paraneoplastic syndrome is a rare autoimmune complication most associated with small cell lung cancer. This case describes a man in his mid-60s with metastatic small bowel adenocarcinoma and nasopharyngeal squamous cell carcinoma who developed confusion, severe dysphagia and progressive weakness. Neurologic evaluation revealed hallucinations, disorientation and lower extremity weakness. Serum and cerebrospinal fluid were positive for anti-Hu (ANNA-1) antibodies, confirming the diagnosis. Anti-Hu disease is associated with a poor prognosis, and despite treatment with high-dose corticosteroids and intravenous immunoglobulin, his neurologic and swallowing deficits persisted. He died within 2 months from progression of his cancer and paraneoplastic disease. This case highlights a rare association of anti-Hu with non-small cell nasopharyngeal and gastrointestinal cancers, expands the spectrum of underlying malignancies linked to this antibody and emphasises the importance of early recognition and timely management of paraneoplastic syndromes in patients presenting with unexplained neurological decline and severe dysphagia.