Lung Adenocarcinoma and Hyperamylasemia Associated with Paraneoplastic Syndrome: A Case Report

Paraneoplastic syndromes are systemic manifestations arising from tumor-associated biochemical or immunologic effects, occurring independently of direct tumor invasion. While common paraneoplastic syndromes such as hypercalcemia and hyponatremia are frequently observed in lung cancer, hyperamylasemia is a rare phenomenon, particularly associated with metastatic lung adenocarcinoma. A 67-year-old male presented with complaints of fatigue and shortness of breath. Laboratory investigations revealed elevated serum amylase (1330 U/L). The patient had no abdominal symptoms, and imaging showed no pancreatic pathology. Chest computed tomography identified a spiculated lesion in the left upper lobe of the lung, and biopsy confirmed a diagnosis of lung adenocarcinoma. Additional evaluations found no other cause for the amylase elevation, leading to a diagnosis of paraneoplastic hyperamylasemia. Following chemotherapy with carboplatin and paclitaxel, a significant reduction in serum amylase levels was observed, alongside partial tumor regression. This case highlights hyperamylasemia as a rare paraneoplastic syndrome in lung adenocarcinoma. Unexpected biochemical abnormalities in cancer patients should be evaluated as potential paraneoplastic syndromes associated with malignancy and closely monitored. In this case, the decrease in amylase levels following chemotherapy supports a paraneoplastic etiology.