Challenging and uncommon diagnosis of long-evolution ascites

Abstract

This is a case report of a 45-year-old Caucasian man with chronic alcoholism. No history of liver disease or asbestos exposure. He complained of ascites during the last 3 years with worsening in the last year with severe ascites development. Diagnostic paracentesis showed SAAG 1.1 and high cellularity with neutrophil count >250 cells/µL. Ascitic fluid cytology revealed reactive mesothelial hyperplasia. Thoracoabdominopelvic ultrasonography/CT/MRI and fludeoxyglucose positron emission tomography/CT showed 'omental cake' pattern suggesting peritoneal carcinomatosis. An exploratory laparoscopy revealed moderate interloop adhesions and necrosis with whitish exudate in the right pelvic excavation. Biochemical/cytological/histological/microbiological study only revealed reactive mesothelial cells, necrosis and lymphohistiocytic inflammatory infiltrate. A second exploratory laparoscopy with liver and peritoneal biopsies and appendectomy/mesoappendix excision showed a well-differentiated tubulopapillary mesothelioma. The patient was referred for intraperitoneal chemotherapy and is undergoing monthly therapeutic paracentesis.

Keywords: gastroenterology; gastrointestinal surgery; gastrointestinal system; malignant disease and immunosuppression.

Figure 1

Thoracoabdominopelvic CT (A) and MRI (B) showing massive free peritoneal effusion and large omental densification like ‘omental cake’ pattern.

Figure 2

Positron emission tomography with diffuse epiploic thickening and nodular areas with mild diffuse fludeoxyglucose uptake, suggesting peritoneal carcinomatosis.

Figure 3

Histopathological study showed reactive mesothelium with no malignancy features and necrosis with lymphohistiocytic inflammatory infiltrate (CD68 positivity) in the right pelvic excavation. (A) Peritoneum, H&E 100x; (B) Pelvic excavation, H&E 100x.

Figure 4

Histopathology of surgical biopsy specimens showed papillary structures with uniform cuboidal mesothelial cells and fibrovascular stroma. Few cells showed atypia or mitotic figures. Necrosis, histiocitary reaction and lymphoplasmocitary inflammatory process were also present. On immunohistochemical study, the tumour cells were calretinin+, desmin+, CK 5/6+, EMA+ (focally), WT1-, CEA- and Ber-Ep4-. Histopathological features were compatible with well-differentiated papillary mesothelioma of the peritoneum without lymphovascular embolisation or lymph node metastasis. (A) Ileocecal appendix, H&E 100x; (B) Omentum, H&E 40x; (C) Peritoneum, H&E 40x.