Abstract A 64-year-old male with a history of coronary artery disease, diabetes, and hypertension presented with progressive weight loss, dysphagia, and muscle weakness. During the past year, he had been hospitalized several times due to aspiration pneumonia. He was admitted for further evaluation. Brain imaging revealed no abnormalities, and cerebrospinal fluid and rheumatologic studies were negative. Electromyography demonstrated findings consistent with Lambert-Eaton Myasthenic Syndrome (LEMS). A paraneoplastic panel revealed positive anti-Hu and calcium channel antibodies, prompting evaluation for malignancy. PET-CT identified a hypermetabolic interlobar lymph node with increased FDG uptake in the left lower lobe. The pulmonology team was consulted. Bronchoscopy and EBUS were performed, showing no endobronchial lesion. Cytology of mediastinal nodes was benign, while the interlobar node specimen was hypocellular and nondiagnostic. The case was discussed in a multidisciplinary tumor board involving thoracic surgery, oncology, and radiology. Mediastinoscopy was considered for tissue confirmation but was deemed high risk given the patient’s ECOG performance score of 3. Since the suspicion of malignancy persisted, a second EBUS was conducted, sampling a distal lobar lymph node (station 12L). Histopathological examination confirmed small cell lung cancer (SCLC) with diffuse positivity for TTF-1 and CD56, along with weak focal staining for synaptophysin. The patient was promptly referred to oncology, and chemotherapy was initiated. After the third treatment cycle, follow-up CT imaging demonstrated a marked decrease in the size of the previously FDG-avid lymph node, indicating a favorable therapeutic response. This case is remarkable for its atypical presentation, where SCLC was detected solely in a single lymph node without an identifiable primary parenchymal lesion. Diagnosis was established through EBUS in a challenging anatomical location, emphasizing the diagnostic value of minimally invasive approaches. The case highlights the importance of considering lung malignancy, particularly small cell lung cancer, in patients with paraneoplastic syndromes such as LEMS, even when imaging shows only isolated nodal involvement. This abstract is funded by: none
Kara et al. (Fri,) studied this question.