Constrictive Pericarditis-A Cloak Camouflaging Lymphoma.

Non-Hodgkin's lymphoma presenting as a primary cardiac lymphoma (PCL) is extremely unusual. Having a predilection for the right side of the heart and accounting for 1% of all cardiac tumours, the difficulty in diagnosing the lesion, owing to the location and vague presenting symptoms and signs, often leads to delayed diagnosis and poor prognosis. In our case report, a middle-aged male was diagnosed with PCL presenting as pyrexia of unknown origin with the help of F18-fluorodeoxyglucose positron emission tomography (18 FDG-PET). PET-CT is an invaluable tool in patients with pyrexia of unknown origin (PUO), especially caused by neoplasms as it helps in localizing the target lesion, aiding in selecting the appropriate intervention for rapid tissue diagnosis. This case serves to sensitize the physicians of PCL presenting with PUO and mimicking a relatively common cardiac tumour such as atrial myxoma.