S2705 Signet Ring Cells in Ascitic Fluid: Innocent Until Proven Guilty?

Abstract

Introduction: Signet ring cell carcinomas (SRCC) are aggressive mucin producing malignancies most commonly found in the gastrointestinal tract. They feature cells with nuclei displaced by intracytoplasmic mucin, resembling signet rings. We present a patient with cirrhosis presenting with recurrent ascites who was found to have signet ring cells in the ascitic fluid without underlying malignancy. Case Description/Methods: A 55-year-old female with cirrhosis secondary to non-alcoholic steatohepatitis and recurrent pancreatitis presented with abdominal fullness, leg swelling and shortness of breath. Her symptoms were not relieved by her home regimen of furosemide and spironolactone. Vital signs were normal. Labs were significant for sodium of 129 millimol/Liter, pro-brain natriuretic peptide of 637 picograms/milliliter, total bilirubin of 3.9 milligrams/deciliter and alkaline phosphatase of 504 units/liter. A paracentesis removed 4.7 liters of straw-colored fluid. Fluid analysis revealed signet ring vacuolated cells. Fluid was sent for further cytology analysis, which showed no evidence of malignant cells. The patient’s symptoms improved after fluid removal. Discussion: There are few reported cases of signet ring cells in ascitic fluid without cytological evidence of malignancy. The presence of signet ring cells in ascitic fluid should prompt further investigation for possible underlying malignancy, which was pursued in this case. Chronic ascites may precipitate shedding of peritoneal mesothelial cells that undergo morphologic changes from fluid absorption, giving the appearance of mucin containing cells of malignant tumors. SRCC can be differentiated from otherwise morphologically similar appearing benign signet ring cells by immunohistochemcical staining. SRCC is associated with infiltrative growth patterns, cellular atypia, nuclear hyperchromasia, prominent nucleoli and mitosis. Furthermore, unlike SRCC, benign signet ring cells have been shown to be strongly positive for E-cadherin and negative for p53 and Ki-67. Therefore, in patients with long standing ascites, it is important to further clarify the finding of signet ring cells with fluid analysis.