Spontaneous regression of small cell lung cancer combined with cancer associated retinopathy

•SR was observed in SCLC combined with cancer associated retinopathy (CAR).•Recoverin antigen on the tumor cells and anti-recoverin antibody in the patient's serum was present.•Activation of recoverin-specific CTL was found.•SCLC was considered to reduce spontaneously by the immunologic reaction.•This is the first report of SR in SCLC combined with CAR.

Spontaneous regression (SR) is defined as the complete or partial disappearance of disease without anticancer treatments. We report a case of SR of small cell lung cancer (SCLC) combined with cancer associated retinopathy (CAR). A 65-year-old woman was admitted to our hospital to examine abnormal shadows of the lung with visual loss. She was diagnosed with SCLC associated with CAR. Subsequent chest X-ray and CT scan showed partial regression of both primary tumor and lymph node metastasis without anticancer treatment. Recoverin antigen was present on the tumor cells and anti-recoverin antibody was observed in the patient's serum. Activation of recoverin-specific antitumor cytotoxic T lymphocyte (CTL) was observed in this patient. SCLC was considered to reduce spontaneously by the activation of recoverin-specific antitumor CTL. To the best of our knowledge, this is the first report of SR in SCLC combined with CAR.