Case Presentation:
A 52‐year‐old woman with a medical history of hypothyroidism and shingles presented to the ED with a monthlong history of abdominal distention, nausea, and decreased appetite. Three years ago, she had had an exploratory laparotomy for presumed perforated diverticulitis, and a serosal biopsy showed mesothelial hyperplasia. One year later, she had an episode of ascites that required a large‐volume paracentesis and resolved uneventfully. One week prior to presentation, she underwent paracentesis that showed 15435 WBCs (predominantly neutrophils), 945 RBCs, and SAAG < 1.1. Bacterial and fungal cultures, AFB stain, and cytology were all negative. Hepatic enzymes, ANA, CA125, CEA, and CA19‐9 also were all normal. Physical examination revealed a moderately distended abdomen with shifting dullness and no tenderness or hepatosplenomegaly. An abdominal and pelvic CT scan only showed large ascites. Paracentesis on admission showed decreased WBCs but was otherwise unchanged. Exploratory laparotomy was considered, but the patient opted for symptomatic treatment and outpatient follow‐up. One month later, a third paracentesis showed atypical mesothelial cells with mild pleomorphism arranged in groups resembling papillary fronds. An immunocytochemical profile of the atypical cells was suggestive of malignant mesothelioma. She subsequently underwent debulking surgery and intraperitoneal mitomycin with hyperthermia.
Discussion:
Peritoneal mesothelioma accounts for a third of all cases of mesothelioma, with an incidence of 100‐300 cases every year in the United States. Only half the patients have had asbestos exposure, and no definitive genetic or environmental associations have been established. Clinical symptoms are usually nonspecific. Fluid cytology offers limited diagnostic value. CT scanning can be used to differentiate between the “dry” and “wet” varieties of peritoneal mesothelioma. The “dry” type may have multiple small masses or a single dominant localized mass with little or no ascites. The “wet” type may reveal widespread small nodules with ascites but no dominant mass. A tissue biopsy is required to make a definitive diagnosis. The clinical course is extremely variable, ranging from a relatively indolent to a highly aggressive course depending on histological type. Metastases are uncommon, and there is currently no staging system for this disease. Treatment includes debulking surgery with intraperitoneal hyperthermic chemotherapy.
Conclusions:
Ascites is a common clinical presentation, and yet peritoneal mesothelioma is a rare cause with a poor prognosis. In the setting of recurrent ascites with an unexplained fluid analysis, hospitalists should consider an aggressive diagnostic workup that includes surgical exploration to rule out rare causes such as peritoneal mesothelioma. Its early diagnosis and treatment may improve overall survival. Although this diagnosis was made via paracentesis, it should be noted that ascitic fluid cytology has a limited diagnostic sensitivity.
Author Disclosure:
B. Xue, University of Michigan, employment; S. Nichani, University of Michigan, employment.