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Título

PARANEOPLASTIC HEMICHOREA ASSOCIATED WITH SMALL CELL LUNG CARCINOMA

RESUMO

CASE REPORT: A 69-year-old male, with a previous history of hypertension and smoking, and no relevant family history, presented with a report of dry cough with progressive worsening over several months, evolving with mild dyspnea on exertion. He was admitted to the Pulmonology service for investigation, and a lung nodule was detected on chest CT. During hospitalization, neurological evaluation was requested due to a painless involuntary movement in the right lower limb, which had started about 2 months before. ​​On physical neurological examination, the patient had right hemichorea with no other abnormalities. He underwent an extensive etiological investigation; a brain MRI showed no significant abnormalities, laboratory tests (including blood glucose, thyroid function, infectious serology, rheumatology screening tests) were also performed with normal results. He underwent biopsy of the pulmonary nodule, and small-cell lung cancer was detected. Symptomatic treatment with a haloperidol was initiated, with partial improvement of the condition. DISCUSSION: Chorea is characterized by involuntary random movements, erratic and migratory, with an abrupt onset, large and short duration, which are repeated with variable intensity. Immune-mediated chorea encompasses several etiologies including paraneoplastic, post-infectious, and idiopathic. Paraneoplastic chorea (PC) is a rare entity, caused by nerve tissue damage by the effects of onconeural autoimmune factors, mediated by T cells. PC is more common around adult age, and small cell lung carcinoma (SCLC) is the most prevalent association. Chorea may predate the discovery of the neoplasm by months to years and may present in conjunction with other movement disorders and encephalopathy. The antibodies most commonly identified in PC are CRMP-5 (CV2) and ANNA-1 (Hu) IgG. In SCLC, approximately 70% are associated with CRMP-5. Tests being false negatives in a minority of cases, which may imply discouraging neoplastic screening in less classic cases. The expected brain MRI finding is basal nuclei hyposignal on T1-weighted sequences and hypersignal on T2/FLAIR. The result and prognosis depend on the diagnosis and early initiation of therapy. FINAL COMMENTS: Although rare, a paraneoplastic etiology must be considered as a differential diagnosis in patients presenting with chorea. Screening for neoplastic conditions should be performed, and early treatment for the underlying malignancy may help decrease morbimortality.

Palavras Chave

Chorea, Paraneoplastic Chorea, Paraneoplastic Syndromes, Neoplasm