The diagnostic utility of PAX8 immunostaining of malignant peritoneal mesothelioma presenting as serous ovarian carcinoma: A single-center report of two cases

Our plain-English summary of The diagnostic utility of PAX8 immunostaining of malignant peritoneal mesothelioma presenting as serous ovarian carcinoma: A single-center report of two cases, by K. Nakamura, K. Nakayama, R. Nagaoka, et al (Oncology Letters, 2017).

The study

• Authors: K. Nakamura, K. Nakayama, R. Nagaoka, K. Nishisako, M. Ishikawa, H. Katagiri, T. Ishibashi, E. Sato, C. Amano, S. Kyo
• Journal: Oncology Letters
• Published: 2017;13(1):263-266
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Malignant peritoneal mesotheliomas (MPMs) are rare and progressive tumors, which may present similarly to primary peritoneal carcinoma or ovarian carcinoma (OC). The current study reports two cases of MPM that initially presented with the features of OC, for which paired box 8 (PAX8) immunostaining was found to be useful for diagnosis. The two patients were women, aged 58 and 56 years, respectively. The primary presenting symptoms and clinical findings included prolonged abdominal pain, abdominal swelling and cough. The two cases were initially diagnosed as OC and were treated with primary debulking surgery. The patient in case 1 had no history of asbestos exposure, while the patient in case 2 did. Final diagnoses were determined based on histological and immunohistochemical results, which included negative PAX8 immunostaining, and which were consistent with MPM. The present cases demonstrated that PAX8 negativity may be a useful diagnostic biomarker for differentiating MPM from OC.

In plain English

This was a report of two cases from Shimane University School of Medicine in Japan. Both patients were women, aged 58 and 56. Imaging first pointed to ovarian carcinoma in both. One woman had no history of asbestos exposure and the other did. The article does not describe the type, source or amount of that exposure. Both women had surgery to remove the uterus, both ovaries and fallopian tubes, and the omentum. A pathologist then diagnosed malignant peritoneal mesothelioma. In both cases the tumor cells tested negative for PAX8, the marker the authors used to tell the two diseases apart. The authors also reported their group's unpublished observation that PAX8 was present in 65 of 67 serous adenocarcinomas. After surgery both women received cisplatin and pemetrexed chemotherapy. Both were alive without disease progression, one 1 year and the other 3 years after finishing that treatment. The authors concluded that PAX8 staining is a useful tool for distinguishing peritoneal mesothelioma from serous ovarian carcinoma. They also concluded that a history of asbestos exposure is not essential for the disease to occur.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Case report of two patients (single center)
• Who was studied: Two women, aged 58 and 56, treated at Shimane University School of Medicine, Izumo, Japan; both were initially thought to have ovarian carcinoma
• Exposure: Asbestos exposure history only: the 58-year-old (case 1) had none and the 56-year-old (case 2) had a history of exposure. No fiber type, source, job or dose is given.
• Main results:
  • Both cases were first diagnosed as ovarian carcinoma and treated with primary debulking surgery
  • The authors could not tell peritoneal mesothelioma from ovarian carcinoma by imaging alone in these cases
  • Case 1 (58-year-old, no asbestos history): the tumor's epithelial-like cells were negative for PAX8 and several other markers. They were positive for calretinin and CAM5.2.
  • Case 2 (56-year-old, asbestos history): the tumor cells were negative for WT1, ER, Ber-EP4 and PAX8. They were strongly positive for calretinin, CK7, CK20, D2-40 and CK5/6.
  • In case 2, CT suggested possible thickening of the pleura but no lung metastasis
  • Case 1 was alive without disease progression 1 year after completing first-line cisplatin and pemetrexed chemotherapy
  • Case 2 was alive without disease progression 3 years after completing first-line chemotherapy
  • The authors' group reported unpublished data showing PAX8 positivity in 65 of 67 serous adenocarcinoma cases (97%). These were ovarian-type cancers, not mesotheliomas.
• The authors' conclusion: The authors concluded that PAX8 immunostaining is a useful tool for differentiating malignant peritoneal mesothelioma from serous ovarian carcinoma. They also concluded that a history of asbestos exposure is not essential for the disease to occur.

Topics

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Carcinoma, Primary Peritoneal Carcinoma, Cytoreductive Surgery, Asbestos Exposure, Biomarker.

Related studies

• PAX8 Expression in a Subset of Malignant Peritoneal Mesotheliomas and Benign Mesothelium has Diagnostic Implications in the Differential Diagnosis of Ovarian Serous Carcinoma — D.B. Chapel, A.N. Husain, et al. (2017)
• The diagnostic and molecular characteristics of malignant mesothelioma and ovarian/peritoneal serous carcinoma — B. Davidson (2011)
• Value of PAX8, PAX2, claudin-4, and h-caldesmon immunostaining in distinguishing peritoneal epithelioid mesotheliomas from serous carcinomas — N.G. Ordóñez (2013)
• Utility of HBME-1 immunostaining in serous effusions — V. Ascoli, C. Carnovale-Scalzo, et al. (1997)
• Utility of CEA and CA 15-3 measurements in non-purulent pleural exudates in the diagnosis of malignancy: A single-center experience — J.M. Porcel, C. Civit, et al. (2017)
• The utility of serum N-ERC/mesothelin as a biomarker of ovarian carcinoma — H. Saeki, A. Hashizume, et al. (2012)

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