Navigating chylous pericardial effusion: a case study and evidence-based review of management options.

Chylopericardium is an uncommon condition characterised by chyle accumulation within the pericardial space, arising idiopathically or secondary to trauma, malignancy, or thoracic surgery. Owing to its rarity, management strategies remain non-standardised. We report a 34-year-old woman with biopsy-proven primary mediastinal B-cell lymphoma complicated by superior vena cava (SVC) obstruction who developed progressively enlarging pericardial effusion. Serial echocardiography demonstrated gradual fluid accumulation without initial haemodynamic compromise. High-risk pericardiocentesis was eventually performed, yielding 480 mL of milky fluid with biochemical confirmation of chyle. She was managed conservatively with a low-fat, medium-chain triglyceride diet, subcutaneous octreotide, and oral midodrine. Drain output declined markedly, and the effusion resolved without recurrence. The patient remained well on follow-up. This case underscores the pathophysiologic interplay between SVC obstruction, impaired lymphatic drainage, and chyle accumulation. Chylopericardium remains diagnostically challenging because of its variable presentation and limited evidence base. Our experience supports that appropriately selected patients may achieve resolution with medical management alone, avoiding operative morbidity. Further studies are warranted to refine treatment algorithms and identify predictors for recurrence or surgical intervention. Conservative therapy – particularly dietary modification and pharmacologic reduction of lymphatic flow – can be effective in selected patients. A multidisciplinary strategy is critical to guide escalation to surgical intervention when indicated.