Lymphohistiocytoid mesothelioma: a rare lymphomatoid variant of predominantly sarcomatoid mesothelioma

Our plain-English summary of Lymphohistiocytoid mesothelioma: a rare lymphomatoid variant of predominantly sarcomatoid mesothelioma, by D.W. Henderson, H.D. Attwood, T.J. Constance, et al (Ultrastructural Pathology, 1988).

The study

• Authors: D.W. Henderson, H.D. Attwood, T.J. Constance, K.B. Shilkin, R.H. Steele
• Journal: Ultrastructural Pathology
• Published: 1988;12(4):367-84
• Type of article: Case report, Review
• Cited by: 51 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Of 394 "definite" mesotheliomas entered in the Australian Mesothelioma Surveillance Program, three bore a striking resemblance to malignant lymphoma by conventional light microscopy, and each was misinterpreted at some stage as lymphoma. The lymphoma-like morphology was a combined result of intense lymphoplasmacytic infiltration and the histiocytoid appearances of the underlying neoplastic cell population. Immunocytochemical analysis demonstrated cytokeratins coexpressed with vimentin within the tumor cells, whereas immunoreactivity for leukocyte common antigen was confined to the smaller lymphoid cells. Electron microscopy of two cases revealed a polymorphous population of fibrohistiocytic cells resembling those typical of malignant fibrous histiocytoma, admixed with lymphocytes and plasma cells, but sporadic cells expressed mesothelial properties in the form of sinuous villiform processes, intracytoplasmic neolumina lined by microvilli, and intermediate filaments that were aggregated into tonofilament bundles in some cells. The ultrastructural appearances, the localization of the tumors to the pleura, with effusion, and absence of anterior mediastinal mass lesions facilitated exclusion of lymphocyte-rich thymoma. In addition, a history of prior occupational exposure to asbestos was elicited in each instance. There was no apparent response to radiotherapy or chemotherapy, and the patients died at 4, 5, and 8 months after presentation. Our observations suggest that immunocytochemical or ultrastructural evaluation is mandatory for accurate diagnosis of all pleura-based lymphomatoid lesions with a mixed large and small cell pattern.

In plain English

This was a case series describing three pleural mesotheliomas, mostly sarcomatoid in type, that looked like lymphoma (a cancer of lymphoid cells) under an ordinary microscope. The three cases came from 394 "definite" mesotheliomas submitted to the Australian Mesothelioma Surveillance Program, which is less than 0.8% of those submitted. Each case was misread as lymphoma at some stage. All three patients were men, and each had a history of past occupational exposure to asbestos. Special stains showed that the tumor cells carried both cytokeratins and vimentin. Electron microscopy of two cases found scattered cells with features of mesothelial cells. There was no apparent response to radiotherapy or chemotherapy, and the patients died 4, 5 and 8 months after presentation. In one case, a compensation panel in Scotland first rejected the claim because the biopsies were read as lymphoma. The panel later accepted the mesothelioma diagnosis after the patient died. The authors concluded that immunocytochemistry or electron microscopy is essential to diagnose these lymphoma-like pleural tumors accurately. They noted that the true frequency may be underestimated.

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 (three case reports with pathology review)
• Who was studied: Three men (aged 54, 73 and 58) with pleural mesothelioma, identified among 394 "definite" mesotheliomas submitted to the Australian Mesothelioma Surveillance Program from 1979 to 1985
• Exposure: Past occupational asbestos exposure in all three men. One case: heavy exposure in shipyards in Scotland and Australia. Another: locomotive maintenance yard and petroleum refinery work lagging boilers and pipes. In the first case, asbestos bodies were found in the lung biopsy. Fiber types were not named.
• Main results:
  • In all three cases, the tumor was misinterpreted as lymphoma at some stage.
  • In all three cases, the tumor cells showed both cytokeratins and vimentin on immunostaining.
  • Staining for leukocyte common antigen was confined to the smaller lymphoid cells, not the tumor cells.
  • Electron microscopy of cases 2 and 3 showed cells resembling malignant fibrous histiocytoma, mixed with lymphocytes and plasma cells. Scattered cells showed mesothelial features.
  • None of the three patients showed an apparent response to radiotherapy or chemotherapy. They died 4, 5 and 8 months after presentation.
  • The authors found no evidence that the lymphoma-like features gave these patients a better outlook.
  • This type made up less than 0.8% of mesotheliomas submitted to the Australian Mesothelioma Surveillance Program.
  • In case 2, a pneumoconiosis compensation panel in Scotland initially rejected the claim because the biopsies were read as lymphoma. After it received the immunostaining and electron microscopy data, the panel conceded the mesothelioma diagnosis after the patient's death.
  • Autopsy of case 3 showed a mesothelioma that was overwhelmingly sarcomatoid in type. It contained one small focus of epithelial differentiation.
  • The lung of case 3 had an asbestos fiber count of 76,000 plus or minus 38,000 coated fibers and 266,000 plus or minus 71,000 uncoated fibers per gram of dry tissue. Asbestos bodies were not identified in the lung tissue examined.
• The authors' conclusion: The authors concluded that immunocytochemistry or electron microscopy is essential for accurate diagnosis of pleura-based lymphoma-like disorders with a mixed large and small cell population.
• Limitations the authors state:
  • The less than 0.8% figure may underestimate how common this type is, because cases diagnosed as lymphoma are likely not sent to mesothelioma registries.
  • The lymphoid reaction may be temporary, so a biopsy taken at one point in time may miss it.
  • The authors had no data on the proportions of T-cell subsets within the tumors.

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, Sarcomatoid, Pleura, Occupational Exposure, Chemotherapy.

Related studies

• Lymphohistiocytoid mesothelioma. An often misdiagnosed variant of sarcomatoid malignant mesothelioma — H.S. Khalidi, L.J. Medeiros, et al. (2000)
• Malignant deciduoid mesothelioma: a rare variant of epithelioid mesothelioma — L. Taylor, D. Cooper, et al. (2019)
• Biphasic malignant mesothelioma with epithelioid and sarcomatoid components (dedifferentiated mesothelioma) and intrapulmonary growth: a rare entity mimicking desquamative interstitial pneumonia — J. Laforga, A. Gonzalez Garcia (2020)
• Lymphohistiocytoid mesothelioma of the pleura — T. Kawai, S. Hiroi, et al. (2010)
• Novel LRRK2 mutations and other rare, non-BAP1-related candidate tumor predisposition gene variants in high-risk cancer families with mesothelioma and other tumors — M. Cheung, Y. Kadariya, et al. (2021)
• Microcystic variant of localized malignant mesothelioma accompanying an adenomatoid tumor-like lesion — H. Umezu, K. Kuwata, et al. (2002)

Browse more research in Ultrastructural Pathology, or return to medical research.