Yellow nail syndrome: a syndrome with prominent manifest involvement of the respiratory system

Yellow Nail Syndrome (YNS) is a rare disorder characterized by the classic triad of yellow nails, lymphedema, and chronic respiratory involvement. We report a 42-year-old male with YNS and childhood-onset symptoms lasting for over three decades. He presented with refractory, recurrent chylothorax that progressed to organized pleural effusion and pleural calcification, complicated by respiratory failure and pericardial effusion. Systemic lymphangiography confirmed severe lymphatic reflux and obstruction. This case highlights the diagnostic and therapeutic challenges of YNS, which often leads to underdiagnosis. Clinicians should screen for extrapulmonary signs, including yellow nails and lymphedema, in patients with unexplained pleural effusion to facilitate early diagnosis and intervention and prevent irreversible disease progression.