Fine-needle aspiration of malignant mesothelioma with unusual morphologic features: a case report

Our plain-English summary of Fine-needle aspiration of malignant mesothelioma with unusual morphologic features: a case report, by U. Kapur, E.M. Wojcik (Diagnostic Cytopathology, 2007).

The study

• Authors: U. Kapur, E.M. Wojcik
• Journal: Diagnostic Cytopathology
• Published: 2007;35(3):174-8
• Type of article: Case report
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant mesothelioma is an aggressive neoplasm linked to asbestos exposure. Most mesothelioma patients present with pleural effusion and the fluid is typically sent for cytological examination. Therefore, cytopathologists are most familiar with features of mesothelioma in fluid preparations. We present here a case of malignant mesothelioma with unusual cytological features diagnosed on FNA. The diagnosis was confirmed by immuno-histochemical and electron microscopic studies. In addition, we compare the cytomorphological features observed in malignant effusion versus fine-needle aspiration.

In plain English

This case report described one patient: an 80-year-old man with worsening shortness of breath, no tobacco use and a past history of asbestos exposure. The article gives no details of fiber type or source. Chest X-rays showed extensive pleural thickening on the left side and no free fluid, so the lesion was sampled with a CT-guided fine-needle aspiration (FNA). Many cells looked unusual. They appeared singly and resembled plasma cells, with small vacuoles in their cytoplasm, and there were also sheets, gland-like groups and multinucleated giant cells. Stains were positive for calretinin and CK5/6 and negative for markers used to identify melanoma and adenocarcinoma. Electron microscopy showed tall, branching, finger-like microvilli. The authors also compared mesothelioma features in FNA samples with those described in fluid samples. No tissue was available for histology, so the exact type of mesothelioma was not known. The authors concluded that, in the appropriate clinical setting with correct use of stains and electron microscopy, malignant mesothelioma can be confidently diagnosed on FNA alone.

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), with a comparison of mesothelioma cell features in fine-needle aspiration versus fluid (effusion) samples
• Who was studied: One 80-year-old male with progressive shortness of breath, no cough, fever or chest pain, and no tobacco use. The authors are from the Department of Pathology, Loyola University Medical Center, Maywood, Illinois. The date of the case is not given.
• Exposure: A past history of asbestos exposure. No fiber type, job, product or dose is given.
• Main results:
  • Chest X-rays showed extensive pleural thickening throughout the left side of the chest, and no free fluid was seen. The lesion was sampled by CT-guided fine-needle aspiration.
  • The aspirate smears showed numerous single cells with a plasmacytoid (plasma-cell-like) appearance, with abundant cytoplasm and an off-center nucleus.
  • The majority of the cells showed multiple small cytoplasmic vacuoles.
  • Rare spindle cells were seen. The authors said these may indicate a biphasic tumor.
  • The tumor cells were positive for calretinin (membranous and nuclear staining) and for CK5/6 (strong cytoplasmic staining).
  • The tumor cells were negative for HMB45, S100, Ber Ep4, B72.3 and CEA. The authors used these results to help rule out malignant melanoma and adenocarcinoma.
  • Electron microscopy of cell block material showed cells with tall, finger-like, branching microvilli.
  • Spaces ("windows") between cells were seen in this FNA specimen. Others had described these as absent or rare in FNA specimens.
  • In the authors' comparison, the characteristic features seen in effusion (fluid) samples are rarely seen on FNA.
• The authors' conclusion: The authors concluded that, in an appropriate clinical setting with correct use of an immunohistochemical panel along with electron microscopy, a confident diagnosis of malignant mesothelioma can be made on FNA alone.
• Limitations the authors state:
  • Because FNA was the definitive diagnostic procedure, no tissue was available for histologic evaluation, so the exact histologic type of this mesothelioma is not known.

Topics

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

Medical terms in this study, explained in our Lexicon: Fine-Needle Aspiration, Malignant Mesothelioma, Neoplasm, Asbestos Exposure, Mesothelioma, Pleural Effusion.

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