Abstract
INTRODUCTION: The diagnosis of a neurological paraneoplasic syndrome is, in the absence of a known oncologic disease, difficult. It implies the recognition of the neurological syndrome, the diagnosis of the oncologic disease, and the establishment of a relationship between both of them, mediated by a congruent profile of antineuronal antibodies. We report a case that exemplifies the diagnostic challenge that this entity poses. CASE REPORT: A 61-year-old woman, non smoker, presented with depressive humour beginning six months earlier, that evolved sub acutely to irritability, insomnia, tremor, visual disturbances e gait difficulties that resulted in inability to walk in the weak previous to the hospital admission. On the neurological exam, it was noticed encephalopathy, ophtalmoparesis, incessant multidirectional nystagmus, pancerebellar syndrome and axial and multi segmental myoclonus. The brain TC and MRI were normal. CSF study revealed monocytic pleocytosis (22/uL), with increased protein levels (89.0 mg/dL) and normal glucose levels. It was identified by TC an image compatible with pulmonary neoplasm of the right inferior lobe, metastasized to the contra lateral lung and invading the pleural and the loco regional lymph nodes. It was determined seropositivity to the antineuronal antibody ANNA 2 (anti-Ri) and raised levels of tumoral markers CA 125 and CA 15-3. The pulmonary lesion was submitted to transthoracic biopsy and the histological exam confirmed the diagnosis of a lung adenocarcinoma. There was not any neurological improvement after treatment with human immunoglobulin (0.4g/Kg/d, during 7 days). The patient died two months after the diagnosis was made. It is highlighted the absence of any respiratory symptoms contemporaneous to the neurological manifestations. CONCLUSION: The case presented is consistent with the diagnosis of opsoclonus myoclonus syndrome associated with lung adenocarcinoma. It is not usual for this entity, rarely seen in adults, to be associated with this histological variety of pulmonary neoplasm.