Beyond the Tumor: A Rare Paraneoplastic Combination Unmasking Lung Cancer

Paraneoplastic syndromes are heterogeneous clinical manifestations that may occasionally reveal an underlying malignancy.We report the case of a 37-year-old man with lung adenocarcinoma who presented with severe hypotonic hyponatremia suggestive of syndrome of inappropriate antidiuretic hormone secretion (SIADH), recurrent hypoglycemia, and an isolated prolonged activated partial thromboplastin time (aPTT), in whom a paraneoplastic origin of these abnormalities was suspected.This uncommon coexistence highlights the importance of considering an occult malignancy in patients presenting with multiple unexplained endocrine and coagulation abnormalities.It also illustrates the challenges of interpreting an isolated prolonged aPTT and the need for a systematic diagnostic evaluation of each abnormality before attributing it to a paraneoplastic mechanism.