A Case of Well-Differentiated Papillary Mesothelioma of the Male Peritoneum: Successful Treatment by Systemic Chemotherapy

Rare Variants of Malignant Peritoneal Mesothelioma: a Literature Review

Primary peritoneal mesothelioma (PM) is a rare and aggressive malignancy that arises from the peritoneum and classified into diffuse malignant peritoneum mesothelioma (DMPM) and borderline variants, viz. multicystic peritoneal mesothelioma (MCPM) and well-differentiated papillary peritoneal mesothelioma (WDPPM). The borderline variants are rarer than conventional DMPM, are less aggressive form accounting for 3-5% of all cases of peritoneal mesothelioma. In this narrative review article, we have discussed the pathogenesis, clinical presentation, natural history, and management of these rarer variants of PM, viz. MCPM and WDPPM. Histologically, MCPM typically consists of small cysts composed of mesothelial epithelium with benign bland cuboidal cells with clear fluids; cells lack cellular atypia and have increased number of mitoses. WDPPM has specific papillary component with myxoid plump cores and single layer of bland mesothelial cells. Both the variants commonly present as incidental finding or symptoms of chronic abdominal pain, chronic pelvic inflammatory disease, pelvic mass, and infertility. In the absence of treatment, these diseases are slow growing with major concerns being that both the variants have malignant transformation capabilities and a high rate of recurrence. In the light of current evidences, it is recommended that MCPM and WDPPM patients should be offered a complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy consisting of cisplatin and doxorubicin. Collaborative multi-institutional studies are needed to generate more data and formulate robust guidelines.

Well-Differentiated Papillary Mesothelioma with Omental Calcifications: A Case Report and Review of the Literature

BACKGROUND Omental calcifications of the peritoneum are typically small and asymptomatic. However, larger psammomatous bodies that cause symptoms such as abdominal pain and bloating are often associated with tumors such as primary serous papillary carcinoma, mesothelioma, or metastatic ovarian cancer. CASE REPORT We describe omental calcifications in a 68-year-old woman who had been asymptomatic for the last 10 years. The case details the histomorphologic features and immunohistochemical signature of a 4.0×3.5×1.0 cm mass consisting of mature adipose tissue that was surgically removed together with an 8.5×6.5×1.8 cm irregular intra-abdominal/mesenteric mass composed of yellow-red fatty tissue. Microscopic sections contained fat with variable clustered classic/psammomatous calcifications, some with a thin epithelioid periphery, in association with a very focal and subtle papillary surface epithelial/mesothelial proliferation. Tumor cell invasion was not observed during examination. Immunohistochemical staining showed that mesothelial cells in the mass were strongly positive for calretinin and focally positive for EMA, CK903, and vimentin. Strong nuclear positivity for PAX8 was also reported. Additional stains were added in response to this pattern, showing strong positivity for CK8, moderate positivity for BAP1, focal positivity for ER, minimal positivity for CD56, and negativity for CK5/6 and D2-40. Three possible explanations are suggested for the phenomenon observed in the pathology slides: reactive mesothelial hyperplasia, well-differentiated papillary mesothelioma, or serous papillary carcinoma of the peritoneum. CONCLUSIONS Findings suggest that these calcifications are a benign, reactive phenomenon, and that the abundance of psammoma bodies may be related to ongoing crops of papillary mesothelial hyperplasia or benign well-differentiated papillary mesothelioma.

Acute severe abdominal pain in a young woman caused by a well-differentiated papillary mesothelioma of the peritoneum

Acute abdominal pain is a common symptom in young women. We describe a patient with acute illness and severe lower abdominal pain. Laboratory tests were normal except for mildly deranged inflammatory markers. No abnormalities were reported on abdominal ultrasonography and MRI, whereas diagnostic laparoscopy revealed a tumour located dorsally from the uterus. We resected the tumour and pathology results showed a well-differentiated papillary mesothelioma of the peritoneum (WDPMP). Microscopy showed evidence of acute ischaemia in the resected lesion, which was likely the cause of the acute abdominal pain. WDPMP is a rare disease that arises from the serous membranes which does not seem to have a relation to asbestos exposure. Generally, WDPMP has a mild clinical course and good long-term prognosis.

Challenging and uncommon diagnosis of long-evolution ascites

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.