11th January 2024

A 19-year-old patient presents to their GP with progressive shortness of breath, weight loss, night sweats and recurrent fevers for the past 4 weeks.

A 19-year-old patient presents to their GP with progressive shortness of breath, weight loss, night sweats and recurrent fevers for the past 4 weeks. They deny any recent travel history or any recent illnesses. On examination, there is dullness to percussion to the right lung base with reduced breath sounds. A chest x-ray confirms presence of a right-sided pleural effusion with a widened mediastinum. A pleural diagnostic aspiration is completed. 

Investigations: 

Pleural fluid protein: 39g/L 

Pleural fluid LDH: 450units/L 

Pleural fluid M, C + S: 85% lymphocytes, gram staining negative. 

Pleural fluid pH: 7.60

Pleural fluid appearance: straw-coloured 

Given the above presentation and pleural fluid features, what is the most likely underlying diagnosis?

Select the SINGLE most appropriate option from the list below. Select ONE option only.