3048 New Onset Ascites Related to Peritoneal Carcinomatosis

Abstract

INTRODUCTION: Peritoneal carcinomatosis (PC) is a metastatic feature in several gastrointestinal malignancies. As one of the most common presenting symptoms is new onset ascites, understanding the workup and typical findings of malignant ascites is crucial for appropriate and time sensitive diagnosis and treatment of such malignancies. CASE DESCRIPTION/METHODS: A 50-year-old female with past medical history significant for hypertension and alcohol abuse presented to the hospital with complaint of intermittent weakness and progressive abdominal fullness for one month. Her exam was notable for subconjunctival palor, abdominal ascites with generalized tenderness, and lower extremity edema. Labs showed leukocytosis and microcytic anemia, with hemoglobin of 5.9. CT abdomen/pelvis revealed cardiomegaly, moderate volume ascites, and diffuse body wall edema. Iron studies were obtained (low iron, low-normal ferritin) and the patient was transfused. A diagnostic paracentesis was completed with resultant SAAG of 0.6. Cytology revealed benign appearing mesothelial cells and histiocytes. Due to the patient's lack of insurance, GI was consulted for inpatient evaluation of iron deficiency. Colonoscopy showed a large (>10 cm) ulcerated lesion in the sigmoid colon with pathology consistent with moderately-differentiated adenocarcinoma. Repeat CT was obtained for staging purposes, showing diffuse peritoneal carcinomatosis, distal colon lesion, L4 vertebral sclerosis, and large volume ascites. The patient was discharged with plans to follow up with GI and oncology to discuss therapeutic options. DISCUSSION: Peritoneal carcinomatosis is defined as the dissemination of cancer cells throughout the periteoneum. About 8% of patients with colorectal cancer present with PC; most commonly with nonspecific symptoms such as fatigue, abdominal pain/fullness, and bowel obstruction. Since new onset ascites is common to PC, it is important to identify malignant ascitic fluid. Malignant ascites related to peritoneal carcinomatosis is mainly caused by subphrenic vessel obstruction and accounts for 7% of ascites cases. A diagnostic paracentesis is indicated, with typical fluid findings of WBC >500, SAAG <1.1, and total protein >2.5. Fluid cytology is important, however sensitivity is affected by the number and quality of specimens used, making the overall sensitivity only about 60-70%. After a diagnosis of malignant ascites is made, the patient should be counseled and referred for evaluation of available therapeutic options.