An Unusual Case of Chylous Ascites: Lymphatic Invasion by Signet-Ring Cell Adenocarcinoma of the Stomach

Abstract

Purpose: To report an unusual case of chylous ascites as the presenting symptom for metastatic gastric cancer. Methods: Case: A previously healthy 53-year-old male presented with shortness of breath, abdominal distension and bilateral lower extremity swelling. On physical exam, the patient had obvious anasarca. Initial laboratory studies were unremarkable except for a serum albumin of 1.8 g/dL and a total protein of 5.0 g/dL. A CT scan of the abdomen demonstrated large ascites but no discrete lesions, focal masses, or lymphadenopathy. The patient then underwent an abdominal paracentesis with removal of a white milky fluid. Fluid analysis revealed: WBC 570 with 45% neutrophils, albumin <1.0, negative cytology, and triglyceride 823 mg/dL. A subsequent EGD showed a 3×4 cm irregular and firm mass in the pre-pyloric area. The duodenum was noted to be very irregular appearing with white opaque spots carpeting the entire observed duodenum. Biopsies were taken. Results: Cell-block preparations of the gastric mass showed a poorly differentiated adenocarcinoma composed predominately of cells with eccentric, hyperchromatic nuclei and abundant foamy cytoplasm which stained focally with mucicarmine. The sections from the duodenal biopsy showed fragments of duodenal mucosa with widely dilated lymphatic spaces filled with clusters of signet ring-type cells, similar to those seen in the gastric biopsy. Further imaging confirmed the presence of bony metastases. Although he was offered palliative chemotherapy, he consciously elected for hospice care and died two weeks later. Conclusion: Chylous ascites is an uncommon finding. The pathogenesis is related to extravasation of chyle into the peritoneal cavity secondary to a disruption in the lymphatic system. The finding of chylous ascites should prompt one to investigate for such a disruption. Considerations in this differential diagnosis should include recent trauma, surgery, infections, and neoplasms such as lymphomas and disseminated abdominal carcinomas. Although there have been only a few reported cases of chylous ascites associated with abdominal malignant neoplasms, there are even fewer cases associated with stomach cancer. In this case, metastatic signet-ring cells filled the lymphatic spaces of the duodenum thereby disrupting normal lymphatic flow. To our knowledge, this patient represents only the second histologically-documented case for chylous ascites due to advanced gastric signet-ring cell carcinoma.