Cytopathology of malignant mesothelioma of the pleura in fine-needle aspiration biopsy

Our plain-English summary of Cytopathology of malignant mesothelioma of the pleura in fine-needle aspiration biopsy, by G.K. Nguyen, M.R. Akin, R.R. Villanueva, et al (Diagnostic Cytopathology, 1999).

The study

• Authors: G.K. Nguyen, M.R. Akin, R.R. Villanueva, J. Slatnik
• Journal: Diagnostic Cytopathology
• Published: 1999;21(4):253-9
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The cytologic findings in fine-needle aspiration biopsy (FNAB) of 9 histologically, immunohistochemically, and ultrastructurally confirmed malignant mesotheliomas of the pleura were reviewed. There were 4 epithelial malignant mesotheliomas (EMM), 3 sarcomatous mesotheliomas (SM), 1 mixed malignant mesothelioma (MMM), and 1 poorly differentiated malignant mesothelioma (PDMM). In FNAB, three EMMs yielded polygonal malignant cells with oval nuclei and prominent nucleoli, singly, in small sheets, and in tridimensional clusters with smooth or lobulated contours. In one EMM, only atypical mesothelial cells with prominent nucleoli were seen singly and in loose aggregates. In FNAB, two SM showed malignant spindle-shaped cells (MSC) with scant, ill-defined cytoplasm singly and in loose clusters. Cohesive clusters of elongated and polygonal cells with ill-defined, clear cytoplasm and pleomorphic nuclei containing small or prominent nucleoli were observed in one SM, with extensive clear-cell changes. In needle aspirates, the MMM showed polygonal malignant cells in clusters admixed with MSC. The PDMM displayed single and clustered large pleomorphic malignant cells, with prominent single or multiple nucleoli. Electron microscopic examination of minute tissue fragments retrieved from the FNAB in 2 cases of EMM revealed epithelial mesothelial cells with well-formed desmosomes and long slender microvilli (LSM) on the free tumor cell surfaces. In one case, LSM in direct contact with collagen fiber bundles in the tumor tissue matrix were observed, supporting the diagnosis of an invasive EMM. Diagn. Cytopathol. 1999;21:253-259.

Copyright 1999 Wiley-Liss, Inc.

In plain English

This study reviewed nine cases of malignant mesothelioma of the pleura sampled by fine-needle aspiration biopsy, a thin needle passed through the chest wall to collect cells. The patients were adults aged 44 to 78. Occupational asbestos exposure was noted in 4; no fiber types were named. Final tissue diagnoses were four epithelial, three sarcomatous, one mixed and one poorly differentiated mesothelioma. Needle samples matched the epithelial type in 3 of the 4 epithelial cases; the fourth showed only atypical mesothelial cells. The three sarcomatous cases and the mixed case were judged suggestive of those types. The poorly differentiated case was read on needle sampling as an anaplastic cancer. Immunostaining of needle-sample smears, done in two patients, supported the diagnosis in one; tumor tissue was immunostained in all nine. Electron microscopy of tiny needle fragments from two patients showed features of mesothelial cells, and in one of them, signs of invasion. Five patients died 6 to 12 months after diagnosis. The authors concluded that diagnosing mesothelioma this way is challenging, with difficulty varying by tumor differentiation.

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 series: a review of cytology laboratory files for pleural mesotheliomas sampled by transthoracic fine-needle aspiration biopsy, compared with tissue diagnoses
• Who was studied: Nine adult patients aged 44 to 78 with malignant mesothelioma of the pleura presenting as pleural-based masses without effusion; seen at hospitals in Alberta and Saskatchewan, Canada, and Loma Linda, California; no study dates given. The text says all were male, but Table I lists patient 8 as female.
• Exposure: A history of occupational asbestos exposure was noted in 4 of the 9 cases; no fiber types, products, jobs or doses were reported
• Main results:
  • Needle aspirates from patients 1 to 3 were consistent with epithelial malignant mesothelioma, matching the tissue diagnosis
  • In patient 4 (epithelial mesothelioma on tissue), the needle aspirate showed only atypical mesothelial cells
  • In patients 5 to 7, aspirates were suggestive of a spindle-cell sarcoma, most likely sarcomatous mesothelioma; tissue confirmed sarcomatous mesothelioma
  • In patient 8, the aspirate suggested a mixed malignant mesothelioma
  • In patient 9, the cytodiagnosis was anaplastic cancer (Table I); tissue immunohistochemistry and electron microscopy were consistent with poorly differentiated malignant mesothelioma
  • Immunocytochemical staining of needle-aspiration smears (CEA and Leu M1) was done in 2 patients and supported the epithelial mesothelioma cytodiagnosis in patient 1 only
  • Tumor tissue sections were immunostained (CEA, Leu-M1, keratin, vimentin and EMA) in all nine cases
  • Electron microscopy of tiny needle-aspirate fragments was done in patients 2 and 4. In patient 4, long slender microvilli in contact with collagen bundles indicated an invasive epithelial mesothelioma.
  • Five of the 9 patients died of the disease 6 to 12 months after diagnosis; the other 4 were lost to follow-up
• The authors' conclusion: The authors concluded that diagnosing malignant mesothelioma by fine-needle aspiration biopsy is challenging, and that the difficulty varies with the degree of tumor differentiation

Topics

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

Medical terms in this study, explained in our Lexicon: Cytology, Mesothelioma, Pleura, Fine-Needle Aspiration, Mesothelial Cells, Spindle Cell, Pleomorphic, Aspirate.

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• Fine-needle aspiration cytology of localized fibrous tumor of pleura — D. Dusenbery, M.M. Grimes, et al. (1992)
• The role of closed pleural needle biopsy in the diagnosis of malignant mesothelioma of the pleura — H.D. Beauchamp, N.K. Kundra, et al. (1992)
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