Peritoneal deciduosis mimicking peritoneal Carcinomatosis: A case report

Our plain-English summary of Peritoneal deciduosis mimicking peritoneal Carcinomatosis: A case report, by J. Casanova, J. Jurgiel, V. Henriques, et al (Gynecologic Oncology Reports, 2021).

The study

• Authors: J. Casanova, J. Jurgiel, V. Henriques, H. Nabais, L.V. Pinto, J.F. Cunha
• Journal: Gynecologic Oncology Reports
• Published: 2021;37:100827
• Type of article: Case report
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Ectopic decidual reaction (or deciduosis) can be rarely seen in the peritoneum and most of the cases in the literature are associated with pregnancy. It is more commonly found in the ovaries, uterus and cervix. Although its pathophysiology is not totally understood, it is accepted that peritoneal deciduosis develops as a result of the progesterone induced metaplasia of subserosal stromal cells during pregnancy. It is important to distinguish this entity from oncologic conditions, namely metastatic carcinoma and mesothelioma. We report an unusual case of a 40 year-old non pregnant patient that presented with imaging findings suggestive of peritoneal carcinomatosis.

© 2021 The Author(s).

In plain English

This article was a case report about one patient, a 40-year-old non-pregnant woman who had never been pregnant. It did not involve asbestos; mesothelioma appeared only as a diagnosis that was considered and ruled out. After she had lower abdominal discomfort, CT and MRI scans suggested cancer spread across the lining of the abdomen (peritoneal carcinomatosis), and the main suspected diagnosis was carcinomatosis of possible ovarian, fallopian tube or peritoneal origin. Her CA 125 blood marker was 11 U/ml. During keyhole surgery the surgeons saw disease in all abdominal quadrants and scored the Peritoneal Carcinomatosis Index at 39/39. Tissue samples showed cells that tested positive for progesterone receptor, desmin and vimentin, and further staining excluded carcinoma and mesothelioma. The final diagnosis was peritoneal deciduosis, a benign growth of pregnancy-type tissue outside the womb, with associated histiocytic peritonitis. Tests found no excess progesterone and no hidden cancer. She received no further treatment and remained without symptoms 36 months after surgery. The authors concluded the case was one of few reports of such extensive deciduosis in a non-pregnant patient mimicking widespread cancer.

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)
• Who was studied: One 40-year-old woman who had never been pregnant (G0P0) and was not pregnant, managed at the Champalimaud Clinical Centre, Lisbon, Portugal
• Exposure: No asbestos or other environmental or occupational exposure was studied; the article does not mention asbestos. Relevant history: rheumatoid arthritis treated with anti-TNF therapy. She reported no endometriosis, no hormonal replacement therapy and no oral contraceptive use.
• Main results:
  • For this patient, the main differential diagnosis was carcinomatosis of possible ovarian, fallopian tube or peritoneal origin
  • In the patient, MRI confirmed the appearance of carcinomatosis but with normal ovaries; her CA 125 at that time was 11 U/ml
  • At laparoscopy, disease was seen in all abdominal quadrants; the Peritoneal Carcinomatosis Index was 39/39, so debulking surgery was judged not feasible
  • A panel of immunohistochemical stains excluded carcinoma and mesothelioma in this patient
  • The final diagnosis was peritoneal deciduosis with associated histiocytic peritonitis
  • The patient received no additional treatment and remained asymptomatic 36 months after the staging laparoscopy
• The authors' conclusion: The authors concluded the case was one of few reports of a non-pregnant patient with deciduosis this extensive, mimicking extensive malignant carcinomatosis. They also stated that when deciduosis is found in a non-pregnant woman, a source of progesterone should be actively searched for.

Topics

Medical terms in this study, explained in our Lexicon: Peritoneum, Carcinoma, Mesothelioma.

Related studies

• Pregnancy Deciduosis Mimicking Abdominal Tuberculosis and Peritoneal Carcinomatosis: A Case Report — A. Musarò, M.P. Bonasoni, et al. (2026)
• Peritoneal well-differentiated papillary mesothelioma coexisting with endometrial adenocarcinoma mimicking peritoneal carcinomatosis: A case report — Y.Y. Chen, P.C. Li, et al. (2020)
• Pregnancy-related peritoneal ectopic decidua (deciduosis): morphological and clinical evaluation — F. Bolat, T. Canpolat, et al. (2012)
• Peritoneal carcinomatosis: patients selection, perioperative complications and quality of life related to cytoreductive surgery and hyperthermic intraperitoneal chemotherapy — G. Glockzin, H.J. Schlitt, et al. (2009)
• Value of laparoscopy before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for peritoneal carcinomatosis — L.H. Iversen, P.C. Rasmussen, et al. (2013)
• CT imaging of peritoneal carcinomatosis and its mimics — A.D. Diop, M. Fontarensky, et al. (2014)

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