Deciduoid mesothelioma: cytologic presentation and diagnostic pitfalls

Our plain-English summary of Deciduoid mesothelioma: cytologic presentation and diagnostic pitfalls, by C.C. Huang, C.W. Michael (Diagnostic Cytopathology, 2013).

The study

• Authors: C.C. Huang, C.W. Michael
• Journal: Diagnostic Cytopathology
• Published: 2013;41(7):629-35
• Type of article: Case report
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We report two cases of malignant deciduoid mesothelioma (MDM), a very rare variant of malignant mesothelioma (MM). Case 1: An 18-year-old male with no history of asbestos exposure presented with worsening abdominal pain, anorexia, and vomiting after a motor vehicle accident. A CT scan showed small amount of ascites and abdominal mass. An exploratory laparotomy revealed multiple yellow tan, firm nodules on the peritoneum and omentum. He received palliative treatment and died 5 months after the diagnosis. Case 2: A 64-year-old female with history of asbestos exposure initially presented with abdominal distension. CT scan showed abdominal mass with a large amount of ascites. A diagnostic laparoscopy revealed multiple peritoneal nodules. She underwent several regimens of chemotherapy over a period of 69 months and is still alive to date. In both cases, features of mesothelial origin were subtle and the smears showed predominantly single cells with marked nuclear atypia. The second case also contained few two-dimensional loose cell clusters with scalloped or hobnail borders. The clusters often exhibited a pseudoacinar structure surrounding a globular extracellular material. Groups of three to four cells often formed doublets and triplets with cell-to-cell windows. Our results show that MDM may not present with the traditional cytological features described in MM and can manifest with more nuclear pleomorphism resulting in erroneous diagnosis. Recognition of the subtle mesothelial features along with the appropriate ancillary tests is essential for accurate diagnosis.

Copyright © 2012 Wiley Periodicals, Inc.

In plain English

This article reports two cases of malignant deciduoid mesothelioma, which the authors call a very rare variant of malignant mesothelioma. Both arose in the lining of the abdomen (peritoneal), and the authors described how the tumor cells looked in abdominal fluid and biopsies. Case 1 was an 18-year-old man with no history of asbestos exposure; his uncle and grandmother had both had mesothelioma. His biopsy was first read as reactive (non-cancerous) changes, and he died 5 months after diagnosis. Case 2 was a 64-year-old woman with a history of asbestos exposure in her school and home. Her first fluid sample, examined at another hospital, was diagnosed as adenocarcinoma. After several chemotherapy regimens she was alive 69 months after diagnosis. In both cases the cells varied strikingly in size and shape, and mesothelial features were not easily recognized. The authors concluded that the tumor's appearance can be subtle and easily overlooked, leading to misdiagnosis, but that careful examination and additional tests can make accurate diagnosis possible.

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 (two cases) describing cytologic and histologic features
• Who was studied: two patients with primary peritoneal malignant deciduoid mesothelioma: an 18-year-old white male (presented 1998) and a 64-year-old white female school teacher (presented 2006)
• Exposure: Case 2 had a history of asbestos exposure in her school and home (fiber type not stated). Case 1 had no history of asbestos exposure, but his uncle and grandmother had a history of mesothelioma.
• Main results:
  • Case 1 (18-year-old male) had no history of asbestos exposure; his uncle and grandmother both had a history of mesothelioma
  • Case 1: the omental biopsy was initially diagnosed as reactive changes
  • Case 1 died 5 months after diagnosis without further therapy
  • Case 2 (64-year-old female): the ascitic fluid was first diagnosed as adenocarcinoma at an outside hospital
  • Case 2 was alive 69 months after initial diagnosis after several rounds of chemotherapy; the authors suggested chemotherapy had a positive impact
  • In both cases the cells showed striking variation in size and shape and a high degree of nuclear pleomorphism
  • In both cases mesothelial features were not easily recognized
  • Some typical mesothelioma features (cellular clasping, morules, spheres) were absent, particularly in Case 1
• The authors' conclusion: The authors concluded that the cytologic appearance of deciduoid mesothelioma can be subtle and easily overlooked, resulting in misdiagnosis, but that careful examination should reveal subtle mesothelial features and prompt ancillary testing that makes accurate diagnosis possible.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Malignant Mesothelioma, Asbestos Exposure, CT Scan, Ascites, Laparotomy, Peritoneum, Omentum.

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• 'Mucin-positive' epithelial mesothelioma of the peritoneum: an unusual diagnostic pitfall — D.S. Cook, R.L. Attanoos, et al. (2000)
• Epithelioid and sarcomatoid malignant pleural mesothelioma in endoscopic gastric biopsies: a diagnostic pitfall — A. Agaimy, P.H. Wünsch (2006)
• Malignant Deciduoid Mesothelioma: case presentation of an exceptional variant and review of the literature — M. Khmou, S. Echcharif, et al. (2017)

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