Histopathological and immunohistochemical features of 14 peritoneal mesotheliomas with clinical outcomes and recent updates

Journal of Cancer Research and Therapeutics 2022 Oct-Dec [Link]

Srushti Karmarkar, Bharat Rekhi, Kedar K Deodhar, Santosh Menon


Background: Malignant peritoneal mesotheliomas (MPMs) are rare tumors with overlapping clinical and histopathological features, especially with epithelial ovarian carcinomas (EOCs). There is no substantial documentation on these rare tumors from our country.

Objective: To study the clinicopathological features including immunohistochemical (IHC) profile and clinical outcomes of 14 MPMs, diagnosed at our institution.

Materials and methods: This was a retrospective study, wherein 14 cases of MPM, occurring in female patients, diagnosed at our institution, between January 2008 and May 2019 were included, after a critical review.

Results: Median age was 54.5 years. Most patients presented with ascites, omental nodularity, and fat stranding. Microscopically, most cases (11, 78.6%) displayed epithelioid morphology, followed by biphasic pattern (2, 14.3%) and a single case of well-differentiated MPM. IHC, diagnostic sensitivity and specificity of calretinin were 100% (13/13) and 85.7%; of HBME1 were 100% (5/5) and 100%; and of podoplanin (D2-40) were 60% (2/5) and 100%. Other positively expressed immunomarkers were epithelial membrane antigen (n = 2/5, 40%), cytokeratin 5/6 (n = 4/4, 100%), and WT1 (n = 9/10, 90%). Most patients (5/12, 41.7%) were treated with chemotherapy. The 3-year disease-free and overall survival rates were 25.7% and 54%, respectively, including improved survival trend in patients with epithelioid type of MPMs.

Conclusion: MPMs are diagnosed with a combination of clinicopathological features and optimal IHC markers. Their differentiation from EOCs and other metastatic carcinomas is imperative in view of significant treatment implications.