CHYLOTHORAX AS A RARE MANIFESTATION OF METASTATIC GASTRIC ADENOCARCINOMA

Abstract

SESSION TITLE: Medical Student/Resident Pulmonary Manifestations of Systemic Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Chylothorax is a pleural effusion characterized by a chyle containing intestinal lymphatic fluid in the pleural space. It usually occurs secondary to disruption of flow within the lymphatic system or thoracic duct. A triglyceride count of >200 mg/dL or a cell count and differential >70% lymphocytes on fluid analysis aids with diagnosis, however, the presence of chylomicrons is the gold standard. Metastatic malignancy accounts for only 2.4% of cases. CASE PRESENTATION: A 51-year-old female presented with complaints of abdominal pain and shortness of breath. Physical examination revealed a non-distended abdomen, tender to palpation in bilateral lower quadrants. Lungs were clear to auscultation bilaterally with reduced air entry in the left lung base. Chest x-ray was remarkable for a left sided pleural effusion with left basilar atelectasis. Computed Tomography (CT) chest showed a left sided pleural effusion. CT abdomen and pelvis revealed gastric wall thickening with upper abdominal and retroperitoneal adenopathy, as well as retrocrural nodes extending into the chest. 18F-Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scan revealed gastric wall thickening, diffuse lymphadenopathy and bilateral pleural based nodules. Left sided thoracentesis was performed and 1100 cc of milky-white fluid was obtained. The effusion contained 300 mg/dL of triglycerides, 104 mg/dL Cholesterol, and 696/mcL white blood cells with 47% lymphocytes. Medical cytology of the pleural fluid was significant for poorly differentiated adenocarcinoma. Patient opted for hospice care and chose not to undergo chemotherapy. DISCUSSION: Chylothorax as a manifestation of gastric adenocarcinoma is rare. Approximately 50% of chylothorax are as a result of malignancy, however only 2.4% are secondary to metastasis. Signs and symptoms of chylothorax are nonspecific, often presenting like an upper respiratory infection. In most cases, respiratory symptoms precede the diagnosis of gastric cancer. Lymphedema is a common concomitant finding. Chylothorax secondary to malignancy usually presents as a result of direct invasion of the thoracic duct, metastasis into the lymphatic capillaries, or external compression of the thoracic duct. In chylothorax of unknown origin where carcinoma is highly suspected, FDG-PET/CT as a form of imaging can be used as an adjunct to help with diagnosis. Management of chylothorax usually involves treating the underlying cause. Methods may be operative or non-operative. Chemotherapy, irradiation and surgery may be employed to treat the underlying gastric adenocarcinoma, however, unless a high level of suspicion is employed and the gastric carcinoma is recognized early, prognosis is generally poor. CONCLUSIONS: Underlying gastric cancer should be considered as a differential, in those with chylothorax of unknown origin, allowing for early diagnosis and better outcomes. Reference #1: Doerr, C., Allen, M., Nichols, F., Ryu, J. Etiology of Chylothorax in 203 Patients, Mayo Clinic Proceedings 2005; 80(7): 867-870 Reference #2: Maldonado, F., Hawkins, F., Daniels, C., Doerr, C., Decker, P., Ryu, J. Pleural Fluid Characteristics of Chylothorax, Mayo Clinic Proceedings 2009; 84(2): 129 Reference #3: Majoor, C., Aliredjo, P., Dekhuijzen, P., Bulten, J., van der Heijden, H. A Rare Cause of Chylothorax and Lymph Edema, Journal of Thoracic Oncology 2007; 2(3): 247-248 DISCLOSURES: No relevant relationships by Akwe Nyabera, source=Web Response