Clear-Cell Mesothelioma of Uterine Corpus: Diagnostic Challenges in Intraoperative Frozen Sections

Our plain-English summary of Clear-Cell Mesothelioma of Uterine Corpus: Diagnostic Challenges in Intraoperative Frozen Sections, by T. Pongsuvareeyakul, K. Saipattranusorn, K. Sukpan, et al (Diagnostics, 2023).

The study

• Authors: T. Pongsuvareeyakul, K. Saipattranusorn, K. Sukpan, P. Suprasert, S. Khunamornpong
• Journal: Diagnostics
• Published: 2023;13(6)
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The clear-cell variant of epithelioid mesothelioma is an extremely rare neoplasm of the peritoneum. It shares histomorphologic features overlapping with a wide variety of tumors including carcinomas and other non-epithelial neoplasms. The diagnosis of peritoneal clear-cell mesothelioma is not always straightforward, despite known immunohistochemistry (IHC) markers. Due to its rarity, this entity may be diagnostically confused with other clear-cell neoplasms, particularly in intraoperative frozen sections. Here, we present a case of clear-cell mesothelioma originating in the uterine serosa that was initially misdiagnosed as clear-cell adenocarcinoma in the intraoperative frozen section. Microscopically, the tumor showed diffuse tubulocystic spaces of variable size lined by clear cells with moderate nuclear atypia. Immunohistochemical staining confirmed the diagnosis of clear-cell mesothelioma. Recognition of this entity, albeit rare, is important as the diagnosis may significantly affect the management considerations. The judicious use of an IHC panel helps to distinguish this tumor from other mimickers.

In plain English

This article is a short case report, in an image-based format, about one patient: a 28-year-old Thai woman in whom a mass beside the uterus was found by chance during a cesarean section. She had no clinical history of asbestos exposure. At surgery, a 9 × 7 × 5.5 cm tumor was found on the outer surface (serosa) of the uterus. The quick frozen-section test done during the operation diagnosed clear-cell adenocarcinoma, a type of carcinoma. That diagnosis led to removal of both ovaries and tubes and lymph node sampling. Later stains confirmed clear-cell mesothelioma: the tumor was positive for calretinin, WT-1 and CK5/6 and negative for markers including BerEP4 and PAX8. A tiny tumor deposit was found on the left ovary, and an incidental stage IA2 cervical cancer was also found. After six cycles of chemotherapy, she was well without evidence of disease 12 months after surgery. The authors concluded that this tumor is a diagnostic challenge for pathologists. They wrote that the extra surgery may not be necessary for mesothelioma in young women who want to preserve ovarian function.

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 (single patient, 'Interesting Images' article)
• Who was studied: One 28-year-old Thai woman, referred to Maharaj Nakorn Chiang Mai Hospital, Thailand, two months after delivery; dates not given
• Exposure: No asbestos exposure reported; the patient had no clinical history of asbestos exposure
• Main results:
  • Before surgery, the patient's CA125 tumor marker was slightly raised at 70.6 U/mL (normal 0 to 35 U/mL)
  • A 9 × 7 × 5.5 cm tumor was found on the serosa of the uterus at the right posterolateral wall
  • The intraoperative frozen-section diagnosis was clear-cell adenocarcinoma involving the uterine serosa
  • According to the authors, the frozen-section diagnosis was the main reason for complete surgical staging, including immediate removal of both ovaries and tubes and lymphadenectomy
  • Under the microscope, the tumor was made of tubulocystic spaces lined by uniform clear cells
  • Stains showed diffuse positivity for mesothelial markers including calretinin, WT-1 and CK5/6
  • Stains were negative for BerEP4, PAX8, Napsin-A, estrogen receptor, RCC, inhibin, GATA3 and TTF-1
  • The Ki-67 proliferative index was 5 to 10% of cells
  • A cluster of atypical clear cells smaller than 0.2 mm on the surface of the left ovary was consistent with metastatic clear-cell mesothelioma
  • An incidental adenoid basal carcinoma was found in the cervix (FIGO stage IA2)
  • The patient received six cycles of adjuvant chemotherapy and hormonal replacement therapy and was well without evidence of disease 12 months after surgery
• The authors' conclusion: The authors concluded that clear-cell mesothelioma is a diagnostic challenge for pathologists. They wrote that recognizing it matters because the diagnosis may significantly affect management, and that a careful panel of stains helps distinguish it from tumors that look similar.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Frozen Section, Epithelioid, Neoplasm, Peritoneum, Carcinoma, Immunohistochemistry, Adenocarcinoma.

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