CRA18 A RARE CASE OF CHYLOTHORAX SECONDARY TO THE PERIVASCULAR EPITHELIOD CELL TUMOR (PEComa): DIAGNOSTIC AND THERAPEUTIC CHALLENGES

Anis Ayishah Mohd Dali¹, Boon Hau Ng¹, Nor Safiqah Sharil², Rose Azzlinda Osman¹, Hsueh Jing Low³, Nik Nuratiqah Nik Abeed¹, Andrea Yu-Lin Ban¹
1Respiratory Unit, Department of Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, Hospital Canselor Tuanku Muhriz, Kuala Lumpur, Malaysia.
2Department of Anesthesiology and Critical Care, Faculty of Medicine, Universiti Kebangsaan Malaysia, Hospital Canselor Tuanku Muhriz, Kuala Lumpur, Malaysia.
3Internal Medical Unit, Faculty of Medicine and Health Science, Universiti Sains Islam Malaysia, Nilai, Negeri Sembilan.

Introduction
Chylothorax due to perivascular epithelioid cell tumour (PEComa), a rare mesenchymal neoplasm, is an extremely uncommon presentation that creates significant diagnostic complexity. This case emphasises the importance of a thorough assessment of persistent pleural effusions with unknown aetiology and demonstrates favourable outcomes using conservative management combined with targeted treatment.

Case report
A 50-year-old woman presented with three weeks of persistent cough and progressive dyspnea following recent treatment for left-sided empyema. Despite completing antibiotics, she developed recurrent left pleural effusion with reduced left-sided breath sounds and elevated inflammatory markers (TWBC 16×10⁹/L, CRP 28 mg/L). Chest radiography confirmed left pleural effusion, while contrast-enhanced thoracic CT revealed bilateral pleural effusions, and an incidental 12.4 × 10.2 × 15.6 cm mass in the left hypochondrium, at the splenorenal space. Initial chest tube drainage yielded 1,560 mL of hemorrhagic serous fluid with elevated LDH (450 U/L) and negative microbiological studies. Persistent daily drainage of 400-500 mL prompted a repeated pleural fluid biochemical analysis, confirming chylothorax with triglyceride levels of 120 mg/dL and cholesterol of 50 mg/dL. CT-guided biopsy of the mass confirmed PEComa. Conservative management with medium-chain triglyceride diet and subcutaneous octreotide (50 mcg three times daily) reduced chylous output to less than 50 mL daily within one week. Targeted therapy with everolimus was initiated for PEComa treatment. Follow-up evaluations at six weeks and three months demonstrated resolution of chylothorax without recurrence.

Discussion
This case emphasises the critical importance of maintaining high clinical suspicion for rare neoplastic etiologies in unexplained persistent pleural effusion. Early recognition through appropriate analysis of pleural fluid enables a timely diagnosis. Effective conservative management, together with targeted therapy with everolimus shows an excellent outcome for PEComa.