%0 Case Reports %T Ascites of Unexplained Origin: A Case Report. %A Alotaibi MA %A Al Othman AM %A Alotaibi MA %A Al Othman AM %J Cureus %V 14 %N 3 %D Mar 2022 %M 35449652 暂无%R 10.7759/cureus.23256 %X Ascites is defined as a massive collection of fluid in the peritoneal cavity, and it is most commonly caused by portal hypertension due to liver cirrhosis, acute liver failure, and heart failure. We report a case of ascites in a 39-year-old male who presented to the ED complaining of abdominal distention, sporadic pain on the epigastric area, unintentional weight loss over the past two months, night sweats, and blood-mixed stool. We conducted several imaging investigations and laboratory studies and none of them revealed any significant findings except for the abdominal CT with contrast, which showed large ascites along with submucosal fat deposition in the long segment of the transverse colon, suggestive of chronic inflammation [probably inflammatory bowel disease (IBD)], omental caking, and thickening. Peritoneal malignancy was highly suspected. A diagnostic/therapeutic paracentesis was performed, through which 8 L of fluid was drained. Cytology was also performed and this showed mostly reactive mesothelial cells, negative acid-fast bacilli (AFB) culture, and negative polymerase chain reaction (PCR). We also discuss the other investigations performed, none of which helped in establishing a diagnosis.