[Multiple paraneoplastic syndromes occurring in the same patient: clinical, imaging and neuro-pathological...

Paraneoplastic neurological syndromes (PNS) are remote effects of cancer, which are not caused by invasion of the tumour or its metastasis, but presumably immunologic mediated. They developed in less than 1% of patients with systemic cancers, most Limbic encephalitis (LE) is the most common clinical paraneoplastic syndrome attainting the CNS (Central Nervous System), and it is characterized by involvement of hippocampus and amygdala; LE is also the only one with clearly defined imaging features. We report a 64 year old man, former smoker, which presented multiple paraneoplastic syndromes, namely LE, opsoclonus-myoclonus, subacute cerebellar degeneration, brainstem encephalitis, sensory-motor neuropathy and inappropriate antidiuretic hormone secretion syndrome (SIADH); these syndromes were identifiable in the clinical and imaging examination, confirmed by the neuro-pathological study. Magnetic Resonance Imaging disclosed on T2 weighted images bilateral hyperintensity within medial temporal lobes, hypothalamus, thalamus, brain stem, upper and medium cerebellar peduncles and upper cervical spinal cord. The underlying tumour was not found in imaging studies or in the autopsy examination. A mediastinal adenopathy depicted a metastasis from low differentiated neoplasm cells, with some signs of neuroendocrine differentiation. With this case we provide a comprehensive illustration of the PNS, from a clinical, imaging and pathological point of view. This report also emphasises the importance of a diagnosis based on early clinical and imaging findings, given that, in most cases the cancer is not apparent.