Lymphohistiocytoid mesothelioma of the pleura

Our plain-English summary of Lymphohistiocytoid mesothelioma of the pleura, by T. Kawai, S. Hiroi, K. Nakanishi, et al (Pathology International, 2010).

The study

• Authors: T. Kawai, S. Hiroi, K. Nakanishi, K. Takagawa, R. Haba, K. Hayashi, K. Kawachi, A. Nozawa, A. Hebisawa, Y. Nakatani
• Journal: Pathology International
• Published: 2010;60(8):566-74
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Lymphohistiocytoid mesothelioma (LHM), reported to be a rare variant of sarcomatoid mesothelioma, is challenging to differentiate from non-Hodgkin's lymphoma due to marked lymphocytic infiltration. To aid accurate recognition of LHM, we examined immunohistochemical, in situ hybridization (ISH) of Epstein-Barr virus RNA (EBER-1) mRNA, fluorescence ISH (FISH) for homozygous deletion of 9p21, and asbestos analysis in four cases (three men and 1 woman). Three patients died, while Case 4 was still alive 19 months after extrapleural pneumonectomy. Histologically, these cases were characterized by heavy lymphocytic infiltration. All neoplastic cells were positive for calretinin, AE1/AE3, and epithelial membrane antigen, but negative for CEA. EBER1 factor was negative. FISH analysis demonstrated homozygous deletion of the 9p21 locus in three of the four cases. In Case 1: (i) autopsy findings showed mesothelioma primarily located in the right parietal pleura, but metastasized into the left lung and abdominal organs; (ii) the histological findings at autopsy indicated sarcomatoid mesothelioma; and (iii) we found asbestos bodies and fibers in extracts from lung tissue (Cases 1 & 4) using digestion with bleaching fluid. LHM, an infrequent variant of sarcomatoid mesothelioma, displayed homozygous deletion of the 9p21 locus (three of four cases), and has a relatively favorable prognosis for the sarcomatoid type.

In plain English

This article reported four cases of lymphohistiocytoid mesothelioma of the pleura. The authors described this tumor as a rare variant of sarcomatoid mesothelioma that can be mistaken for non-Hodgkin's lymphoma. The patients were three men and one woman, aged 52 to 63, from four hospitals in Japan. Only Case 4, a construction worker, had a confirmed history of asbestos exposure. Three patients died, at 3, 12 and 36 months after diagnosis. Case 4 was alive 19 months after extrapleural pneumonectomy. In all four, tumor cells stained positive for calretinin, AE1/AE3 and epithelial membrane antigen. Tests for Epstein-Barr virus were negative. A genetic test found homozygous deletion of the 9p21 locus in three of the four cases. In Case 1, the tumor seen at autopsy looked like sarcomatoid mesothelioma. Lung tissue counts, given per gram of dry lung, were 157 asbestos bodies and 1259 fibers in Case 1, and 1016 bodies and 3812 fibers in Case 4. Fiber types were not reported. The authors concluded that this tumor is a very rare variant of sarcomatoid mesothelioma with a possible relationship to asbestos exposure.

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 (four cases) with pathology, immunohistochemistry, electron microscopy, in situ hybridization, FISH and lung asbestos analysis
• Who was studied: Four patients with lymphohistiocytoid mesothelioma of the pleura (three men, one woman, aged 52 to 63, mean 59) from four hospitals in Japan
• Exposure: Only Case 4 (a construction worker for 30 years) had a confirmed history of asbestos exposure. The asbestos history of Case 1 was unknown. Asbestos bodies and fibers were counted in lung tissue from Cases 1 and 4. Fiber types were not specified.
• Main results:
  • Three patients died at 3, 12 and 36 months after diagnosis. Case 4 was alive 19 months after extrapleural pneumonectomy.
  • In all four cases, tumor cells were positive for calretinin, cytokeratins AE1/AE3 and epithelial membrane antigen.
  • In situ hybridization for the Epstein-Barr virus marker EBER-1 was negative.
  • FISH showed homozygous deletion of the 9p21 locus in three of the four cases. Case 1 did not have the deletion.
  • The lymphocytes infiltrating the tumors were CD8-positive cytotoxic T-cells.
  • In Case 1, the autopsy found a tumor mainly in the right parietal pleura that had spread to other organs. At autopsy its microscopic appearance was that of sarcomatoid mesothelioma.
  • Asbestos bodies and fibers were found in lung tissue from Cases 1 and 4, with counts given per gram of dry lung. Case 1 had 157 bodies and 1259 fibers per gram. Case 4 had 1016 bodies and 3812 fibers per gram.
  • The authors judged that the Case 1 asbestos body count did not suggest occupational or environmental asbestos exposure.
  • Median survival in these four cases was 15 months.
• The authors' conclusion: The authors concluded that lymphohistiocytoid mesothelioma is a very rare variant of sarcomatoid mesothelioma with a possible relationship to asbestos exposure. They added that it tends to develop at the mediastinal pleura and has a relatively favorable prognosis among sarcomatoid mesotheliomas.
• Limitations the authors state:
  • The clinical history of asbestos exposure in Case 1 was not known.
  • The authors stated that large-scale pathological and epidemiological research will be needed in the future.

Topics

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

Medical terms in this study, explained in our Lexicon: Lymphohistiocytoid, Mesothelioma, Pleura, Sarcomatoid, Fluorescence In Situ Hybridization (FISH), Homozygous Deletion, Extrapleural Pneumonectomy (EPP), Calretinin.

Related studies

• Lymphohistiocytoid mesothelioma of the pleura: a case report with cytological findings — F. Tresserra, M. Castella, et al. (2013)
• Lymphohistiocytoid mesothelioma: a rare lymphomatoid variant of predominantly sarcomatoid mesothelioma — D.W. Henderson, H.D. Attwood, et al. (1988)
• Lymphohistiocytoid mesothelioma. An often misdiagnosed variant of sarcomatoid malignant mesothelioma — H.S. Khalidi, L.J. Medeiros, et al. (2000)
• Lymphohistiocytoid mesothelioma: a clinical, immunohistochemical and ultrastructural study of four cases and literature review — D.X. Yao, J. Shia, et al. (2004)
• Localized malignant lymphohistiocytoid pleural mesothelioma — A. Ouazzani, B. Rondelet, et al. (2011)
• Solitary fibrous tumor of the pleura. An immunohistochemical, electron microscopic and tissue culture study of a tumor producing insulin-like growth factor I in a patient with hypoglycemia — E.H. Strøm, F. Skjørten, et al. (1991)

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