RESUMEN
BACKGROUND: The Guillan-Barré syndrome (GBS) is the most common acute disease of the peripheral nervous system, often necessitating ICU care. Although no clear paraneoplastic syndrome has been defined, it has been known to occur together with several types of cancer. METHODS: We present the case of a 35-year-old man with acute flaccid paralysis and cervical lymphadenopathy. RESULTS: the patient was diagnosed with a severe presentation of GBS and papillary thyroid cancer. After surgical treatment for his cancer, his condition improved and he reached a nearly full recovery. CONCLUSION: our case concerns a young man in whom a severe presentation of GBS led to the diagnosis of thyroid cancer. To our knowledge, this represents the first reported case of this association.