Spontaneous Regression of Small Cell Lung Carcinoma and Associated Hemichorea

The spontaneous regression (SR) of cancer is defined as either partial or complete, and temporary or permanent, disappearance without appropriate treatment for the disease, and this phenomenon is rare in the case of small cell lung carcinoma (SCLC). We herein report an 83-year-old woman who presented with left-sided hemichorea associated with anti-SOX1 (SOX1-Ab) and -CV2/CRMP5 (CV2/CRMP5-Ab) antibodies with SR following a 7-year interval free of disease progression of SCLC. Hemichorea can present with the coexistence of anti-SOX1 and CV2/CRMP5-Ab with SR after a long interval free of SCLC. The immune response associated with these onco-neural antibodies may become independent of the original tumor trigger and remain active for many years.