Recurrent pleural effusions and yellow nails - what’s the cause?

An interesting but difficult to diagnose case

A 58-year-old male with a history of recurrent pleural effusions presents with worsening dyspnoea and lower extremity oedema. 

Examination reveals bilateral pitting oedema of his legs and feet and yellow, dystrophic nails on his fingers and toes. Chest X-ray demonstrates a large right pleural effusion.