Bilateral chylothorax revealing follicular lymphoma: A case report

Introduction: Chylothorax is a rare condition resulting from the accumulation of chyle within the pleural space secondary to disruption, obstruction, or rupture of the thoracic duct. Bilateral chylothorax represents a particularly rare clinical presentation and can compromise the patient's functional and nutritional prognosis.
Case Presentation: We report the case of a 61-year-old man with a history of type 2 diabetes mellitus and active chronic smoking who was admitted for progressively worsening dyspnea associated with lower-limb edema and abdominal distension, without any other respiratory or systemic symptoms. The condition evolved in a context of apyrexia and preserved general health status.
Clinical examination revealed a hemodynamically stable patient with no signs of respiratory distress. Bilateral pitting edema of the lower extremities and signs of bilateral pleural effusion syndrome were noted. Chest radiography demonstrated bilateral pleural effusions of moderate volume, more pronounced on the left side.
Diagnostic thoracentesis yielded a milky pleural fluid. Biochemical analysis of the pleural fluid revealed a protein level of 4.7 g/dL, lactate dehydrogenase (LDH) of 102 U/L, triglycerides of 246 mg/dL, and cholesterol of 75 mg/dL. A diagnosis of chylothorax was therefore established, and pleural drainage was performed.
As part of the etiological workup, thoraco-abdomino-pelvic computed tomography and positron emission tomography-computed tomography were performed. These investigations revealed cervical, mediastinal, and abdominal lymphadenopathy suspicious for malignancy, as well as a large retroperitoneal abdominal mass causing compression of the inferior vena cava, associated with bilateral pleural effusions predominantly on the left side.
A right inguinal lymph node biopsy was subsequently performed. Histopathological examination, supplemented by immunohistochemical analysis, established the diagnosis of low-grade follicular lymphoma.
The clinical course was marked by recurrence of the chylous pleural effusion despite initial drainage, requiring multidisciplinary management and initiation of specific treatment for the underlying hematologic malignancy.
Conclusion: Bilateral chylothorax remains a rare clinical entity, the diagnosis of which relies on pleural fluid analysis. Early management, together with treatment of the underlying etiology, is crucial in determining the prognosis.