Cavitary Pulmonary Infarction Mimicking Malignancy: A Diagnostic Challenge Resolved by Conservative Management.

Cavitating pulmonary infarction is an uncommon complication of pulmonary embolism (PE) that can closely mimic lung malignancy or necrotising infection on imaging. We report the case of a 72-year-old man with a history of heavy smoking who presented with subacute cough, dyspnoea, anorexia, and weight loss. Imaging revealed bilateral PE with right heart strain and a large, thick-walled cavitary lesion in the right lower lobe. Extensive microbiological, cytological, and autoimmune testing did not identify infection, vasculitis, or malignancy. Following multidisciplinary team discussion, the patient was managed conservatively with anticoagulation and a short empirical antibiotic course. Serial imaging demonstrated complete resolution of the cavity and emboli over eight months, with full clinical recovery. This case underscores the importance of correlating imaging findings with vascular anatomy, maintaining a high index of suspicion for pulmonary infarction in patients with coexisting PE, and using a structured, multidisciplinary approach to avoid unnecessary biopsy or surgery when conservative management is likely to be curative.