A case of sarcomatoid malignant peritoneal mesothelioma diagnosed by laparoscopy

Our plain-English summary of A case of sarcomatoid malignant peritoneal mesothelioma diagnosed by laparoscopy, by M. Kobayashi, K. Masuda, Y. Noda, et al (Gynecologic Oncology Reports, 2020).

The study

• Authors: M. Kobayashi, K. Masuda, Y. Noda, J. Tanizaki, E. Yamabe, A. Tanaka, N. Koumura, K. Kozasa, H. Naoi, H. Otsuka, T. Yokoi
• Journal: Gynecologic Oncology Reports
• Published: 2020;34:100642
• Type of article: Case report
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

•Malignant peritoneal mesothelioma, particularly the sarcomatoid type, is rare and aggressive.•Accurate diagnosis by ascites cytology is difficult.•Histological examination such as laparoscopy aids in diagnosis.•There is no clear consensus treatment for MPM and an extensive research program is needed.

© 2020 The Authors.

In plain English

This case report described one 51-year-old woman who came to the authors' hospital with a small lump in her lower right abdomen. The article states she had never been exposed to asbestos and had no family history of malignant mesothelioma; genetic testing was not done. A CT scan showed many solid tumors in the abdomen, including a 10 cm tumor between the liver and right diaphragm. Testing of fluid from her abdomen (ascites cytology) did not detect mesothelioma and instead suggested serous carcinoma or poorly differentiated tumors. Tissue samples taken during laparoscopy led to a diagnosis of sarcomatoid malignant peritoneal mesothelioma. After four cycles of pemetrexed and cisplatin the tumors had shrunk, but her kidney function had declined. During a treatment pause the tumors grew markedly; she moved to supportive care only and died 6 months after diagnosis. The authors concluded that ascites cytology has low diagnostic accuracy and that tissue examination, such as by laparoscopy, is useful.

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 (one patient)
• Who was studied: One 51-year-old woman seen at the authors' hospital (the authors are affiliated with Kaizuka City Hospital, Osaka, Japan). She had had her right ovary and fallopian tube removed two years earlier for a fibroma of the right ovary.
• Exposure: None reported: the article states the patient had never been exposed to asbestos and had no family history of malignant mesothelioma.
• Main results:
  • CT imaging showed a solid tumor of about 2.7 cm in the lower right abdomen. It also showed a 4 cm tumor on the left side of the uterus, a 10 cm tumor between the liver and the right diaphragm, and many solid tumors in the abdominal cavity.
  • Tumor markers were normal except CA-125, which was 156.2 U/mL.
  • At laparoscopy, the lump the patient could feel turned out to be in the abdominal wall, outside the abdominal cavity. Diffuse, widespread masses and nodules were found inside the peritoneal cavity.
  • Ascites fluid cytology did not detect mesothelioma; serous carcinoma and poorly differentiated tumors were suspected instead.
  • On tissue examination, epithelioid-type structures made up only 1 to 2% of the mass. Most of the mass was sarcoma-type tissue composed of spindle-shaped to round cells.
  • The cells stained positive for the mesothelioma markers calretinin, D2-40, cytokeratins 5/6 and EMA, but negative for WT1. They were negative for the carcinoma markers CEA, MOC31, Ber-EP4, Pax8 and ER, and positive for AE1/AE3 and CAM5.2. The final diagnosis was sarcomatoid malignant peritoneal mesothelioma.
  • Systemic chemotherapy began a month after the biopsy: pemetrexed 500 mg/m2 and cisplatin 75 mg/m2 every 21 days.
  • After four cycles, CT showed the masses had diminished but kidney function had decreased. During the wash-out period for kidney recovery, the tumors increased markedly in size.
  • Aggressive treatment was replaced with best supportive care. The patient died one month later, 6 months after diagnosis.
  • Genetic testing was not performed on this patient.
• The authors' conclusion: The authors concluded that the diagnostic accuracy of ascites cytology is low, so tissue (histological) examination such as laparoscopy is useful. They also concluded that malignant peritoneal mesothelioma, particularly the sarcoma type, is rare, has a poor prognosis and has no consensus treatment, and that an extensive research program is needed.

Topics

Medical terms in this study, explained in our Lexicon: Sarcomatoid, Peritoneal Mesothelioma, Ascites, Cytology.

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