Diuretic-responsive “Tumor”: A Case of Pseudotumor in the Lung Fissure

A BSTRACT Phantom tumor, also referred to as vanishing tumor, is a transient interlobar pleural effusion typically observed in patients with congestive heart failure. It can closely mimic a pulmonary mass on chest radiography, often leading to diagnostic uncertainty. We report the case of a 48-year-old male with known ischemic heart disease and reduced ejection fraction who presented with orthopnea. Chest radiograph revealed a well-defined interlobar opacity suggestive of a mass lesion. Following optimization of heart failure management with diuretics, the opacity resolved completely within 72 hours, confirming the diagnosis of phantom tumor. Early recognition of this condition is essential to avoid unnecessary investigations and invasive procedures.