Cytopathology of malignant mesothelioma: a study of its patterns and histological bases

Our plain-English summary of Cytopathology of malignant mesothelioma: a study of its patterns and histological bases, by L. DiBonito, G. Falconieri, I. Colautti, et al (Diagnostic Cytopathology, 1993).

The study

• Authors: L. DiBonito, G. Falconieri, I. Colautti, D. Bonifacio Gori, S. Dudine, L. Giarelli
• Journal: Diagnostic Cytopathology
• Published: 1993;9(1):25-31
• Cited by: 25 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We have reviewed the effusion cytology of 51 cases of histologically proven malignant mesothelioma of the pleura (49 cases) and the peritoneum (2 cases). The patient group included 45 males and 6 females, aged 45-83 yr. A cytological diagnosis of malignancy had been rendered on 43 cases, and in 30 of them it was consistent with, or at least suggestive of, a mesothelioma. Diagnostic clues, especially evident in epithelial and biphasic tumors were hypercellularity and/or morular aggregates of malignant cells showing scalloped borders and nuclei with dense chromatin and evident nucleoli. Cytomegaly with multinucleation was also frequently observed. Reactive mesothelial cells were often present along with other non specific features such as red blood cells, fibrin, necrotic debris. In 13 cases, a diagnosis of malignancy was entertained but mesothelioma, although considered, was not reported out because of scantiness of material. In four cases, adenocarcinoma was erroneously diagnosed for the presence of deceptive cell vacuoles. In eight cases, no diagnostic cells were recovered in repeated effusions. The first diagnosis was a cytologic one in 37 patients, Tissue study was performed on autopsy (35 patients) and surgical material. The latter was the only source of histology in six cases. Immunocytochemical investigation was negative for carcinoembryonic antigen in all but one tested cases (1/21) and positive for human milk fat globulin in about one-half of the epithelial and biphasic tumors. In 18 of 21 cases, positivity for combined high- and low-molecular-weight keratins was detected.(ABSTRACT TRUNCATED AT 250 WORDS)

In plain English

This retrospective study, from the Department of Anatomic Pathology in Trieste, Italy, reviewed fluid samples (pleural and peritoneal effusions) from 51 patients with tissue-proven malignant mesothelioma seen between 1984 and 1990. There were 49 pleural and 2 peritoneal cases, in 45 men and 6 women aged 45 to 83. The authors compared the cells seen in the fluid with the tissue findings. Malignant cells were recognized in 43 of the 51 cases, and mesothelioma was diagnosed or suggested in 30. In 13 cases cancer was reported but its origin could not be settled, and in four of these adenocarcinoma was wrongly suggested. Useful clues included tiny cell clusters with scalloped borders. Of 21 cases tested with antibody stains, one was positive for CEA, a marker usually negative in mesothelioma. A history of asbestos exposure was recorded in 14 patients, and fiber types were not named. The authors concluded that experts can recognize mesothelioma in fluid samples, but that antibody stains have limited practical value because they are not specific.

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: Retrospective study comparing effusion cytology (cells in body fluid) with histology (tissue from surgery or autopsy)
• Who was studied: 51 cases of histologically proven malignant mesothelioma (49 pleural, 2 peritoneal) seen from 1984 to 1990 at the Department of Anatomic Pathology, University of Trieste, Italy. There were 45 males and 6 females aged 45 to 83 years at initial diagnosis. Eight cases were later excluded for inadequate cytologic material, leaving 43 (41 pleural, 2 peritoneal).
• Exposure: The study was about diagnosis, not exposure. Clinical records were checked for previous occupational asbestos exposure. A history of asbestos exposure was found in 14 cases. No fiber types, products or doses are given.
• Main results:
  • Malignant cells were recognized in fluid samples in 43 of the 51 cases.
  • Mesothelioma itself was diagnosed from cytology in 30 of these 43 cases, including the two peritoneal cases. This was 27 diagnostic or consistent with mesothelioma, plus 3 suggestive.
  • In 13 cases reported as 'malignant', the authors could not determine where the cancer cells came from. In four of these, adenocarcinoma was wrongly suggested because of deceptive vacuoles in the cells.
  • The first diagnosis of malignancy was made from cytology in 37 of the 43 cases (86%).
  • The authors found tiny cell clusters (morulae) with scalloped borders and a dense chromatin pattern especially useful as diagnostic clues.
  • Among the 21 cases tested by immunocytochemistry:
• HMFG-2 was positive in 10 epithelial and biphasic mesotheliomas.
• High-molecular-weight keratins were positive in 18.
• Low-molecular-weight keratins were seen in 8 slides.
• CEA was negative in all but one case, an autopsy-confirmed pleural mesothelioma.
  • 35 of the 43 patients died during follow-up. Their average survival was 10.8 months after initial diagnosis, with a range of 1 to 48 months.
  • Five patients had no reported previous occupational risk. One of them was a housekeeper who developed peritoneal mesothelioma.
• The authors' conclusion: The authors concluded that mesothelioma can be recognized in fluid cytology with confidence, especially in epithelial or biphasic tumors. They said that in expert hands it can be distinguished from reactive conditions and from metastatic adenocarcinoma. They considered immunoperoxidase (antibody) methods to have limited practical value because the staining patterns are not specific.
• Limitations the authors state:
  • The antibody markers used are not specific to mesothelioma, and the same staining pattern can occur in other lesions.
  • Immunocytochemical testing of the sarcomatous mesotheliomas was unreliable because there were few cells and probable necrosis.
  • When reactive mesothelial cells are plentiful, they can obscure or prevent a diagnosis of mesothelioma.

Topics

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

Medical terms in this study, explained in our Lexicon: Cytopathology, Malignant Mesothelioma, Cytology, Pleura, Peritoneum, Mesothelioma, Biphasic Mesothelioma, Reactive Mesothelial Cells.

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