Paraneoplastic Neurological Syndrome-associated Antibody-positive Small-cell Lung Cancer Diagnosed with Preceding Neurological Symptoms: a Case Series

Abstract

Background. Patients with malignant tumors are sometimes complicated with various neurological disorders, a group of which is known as paraneoplastic neurological syndrome (PNS) and is caused by autoimmune mechanisms. We herein report two cases of PNS in which preceding neurological symptoms led to the diagnosis of small-cell lung cancer (SCLC), and PNS-related antibodies decreased in response to treatment. Case 1. A 63-year-old woman was presented to the emergency department with impaired consciousness. Imaging tests could not identify the cause of her impaired consciousness. Subsequently, a growing mass was found in her chest. Accordingly, the patient was diagnosed with PNS associated with limited-stage SCLC, and treatment was initiated with cisplatin, etoposide, and accelerated hyperfractionation radiotherapy. Her neurological symptoms disappeared with the tumor reduction and decrease in PNS-related antibodies. Case 2. A-73-year-old woman patient presented with an abnormal shadow in her chest. Previously, the patient had her several epileptic seizures. Extensive-stage SCLC and PNS were diagnosed. Treatment was initiated with carboplatin, etoposide, and atezolizumab. The tumor shrank with treatment, and her neurological symptoms improved, while her PNS-related antibodies disappeared. Conclusion. In both cases, the neurological symptoms improved with the response of the primary tumor to treatment, and PNS-related antibodies decreased.