Pleomorphic carcinoma of the lung with paraneoplastic fever as presentation.

Pulmonary pleomorphic carcinoma (PPC) is a rare, highly aggressive variant of non-small cell lung cancer (NSCLC), comprising 0.1-0.4% of all pulmonary malignancies. While lung cancers typically present with symptoms like cough and hemoptysis, paraneoplastic syndromes are observed in about 10% of cases. Paraneoplastic fever as an initial manifestation is extremely rare. We present a rare case of PPC with neoplastic fever, emphasizing the importance of paraneoplastic syndromes during the evaluation of lung cancer. Surgical resection successfully alleviates neoplastic fever, highlighting the need to recognize paraneoplastic fever as a diagnostic challenge and consider it as a differential in cases of unexplained fever for prompt intervention.