TABLE 1.

Differential diagnosis of lymphoid proliferations

Condition	Patient presentation	Radiological features	Microbiological correlation
Primary pleural lymphoma (non-Hodgkin lymphoma)	Patient can suffer from autoimmune diseases or chronic inflammation; in some cases, patients have no history of medical conditions	Pleural nodules, pleural thickenings, mediastinal mass, thoracic lymphadenopathy; pleural effusion can be unilateral (sometimes as chylothorax)	Unclear/none in particular
Primary effusion lymphoma (PEL)	Immunocompromised, transplanted or cirrhosis patients	Absence of nodules or masses; pericardial and peritoneal involvement	HHV-8, HIV, HBV, others
Pyothorax-associated lymphoma (PAL)	Patients may have history of chronic pleuritis or empyema, pleural TB (especially past artificial pneumothorax therapy) or immunocompromised patients with EBV infection	Pleural mass, invasion of surrounding tissue (ribs), empyema	EBV, Mycobacterium tuberculosis, others

HHV-8: human herpesvirus-8; HBV: hepatitis B virus; EBV: Epstein–Barr virus; TB: tuberculosis.