Abstract Introduction Chylothorax is a rare cause of pleural effusion, accounting for approximately 3% of cases. Etiologies are classified as traumatic or non-traumatic, with lymphomas being the most common non-traumatic cause. Mechanisms for chylothorax formation include direct tumor infiltration of the thoracic duct and obstruction of lymphatic flow. We present a case of non-traumatic chylothorax secondary to mantle cell lymphoma (MCL). Presentation A 70-year-old female with a 51-pack-year smoking history presented with exertional dyspnea and unintentional weight loss. Physical examination revealed absent breath sounds over the left hemithorax and axillary lymphadenopathy. Laboratory studies showed elevated lactate dehydrogenase (298 U/L). Chest radiography demonstrated a large left pleural effusion with complete lower-lobe atelectasis. CT of the chest, abdomen, and pelvis revealed extensive mediastinal, mesenteric, and retroperitoneal lymphadenopathy with massive splenomegaly, concerning for lymphoma. A chest tube drained nearly 2 L of thick, beige-colored pleural fluid. Pleural fluid analysis showed protein 3.2 g/dL (serum 5.5 g/dL), triglycerides 557 mg/dL, cholesterol 88 mg/dL, and negative cultures, consistent with an exudative chylous effusion. She was started on a low-fat diet. Cytology and immunohistochemistry from an axillary lymph-node biopsy were positive for Cyclin D1 and SOX11, confirming MCL. The patient was started on chemotherapy; however, her high-output chylothorax persisted. Thoracic-duct embolization was attempted twice but failed due to challenging anatomy. She was deemed a poor surgical candidate for duct ligation. After a goals-of-care discussion, a PleurX catheter was placed for symptom relief, and she was discharged home. Discussion Non-traumatic chylothorax may initially present subtly with mild nutritional deficiencies and progressive weight loss. Persistent high-output chylothorax ( 1 L/day) carries significant morbidity and a high mortality rate of up to 50%. Diagnosis is confirmed by identifying chylomicrons via lipoprotein electrophoresis, though this test is not widely available. A pleural triglyceride level 110 mg/dL is a reliable alternative. Complications include pulmonary functional decline, malnutrition, immunosuppression, and fluid imbalance. While chylothorax is most commonly associated with indolent lymphomas such as non-Hodgkin variants, reports of refractory high-output chylothorax secondary to MCL remain scarce. Additionally, there are limited data describing management outcomes after failed thoracic-duct embolization, underscoring the variability in lymphatic involvement patterns among lymphoma subtypes. Management requires a multidisciplinary approach involving hematology-oncology, interventional radiology, nutrition, palliative care, and thoracic surgery. When conservative and interventional measures fail, surgical ligation is considered a last resort due to its high complication risk. This abstract is funded by: None
Pearose et al. (Fri,) studied this question.