Mediastinal and pleuropulmonary myeloid sarcoma with HBME1 and podoplanin expression. A diagnostic pitfall

Our plain-English summary of Mediastinal and pleuropulmonary myeloid sarcoma with HBME1 and podoplanin expression. A diagnostic pitfall, by D. Suárez-Vilela, F.M. Izquierdo (APMIS, 2020).

The study

• Authors: D. Suárez-Vilela, F.M. Izquierdo
• Journal: APMIS
• Published: 2020;128(1):65-68
• Type of article: Case report, Letter
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This letter to the editor reported a single case: a 60-year-old man with general symptoms, shortness of breath and fluid around the lung (pleural effusion). A scan showed an 11 cm mass in the left lung, a large left pleural effusion, deposits on the pleura and enlarged lymph nodes in the mediastinum. The patient died 4 months after symptoms began, without a diagnosis or treatment. On the first round of staining of biopsy tissue, the tumor cells stained for HBME-1 and D2-40 (podoplanin), markers used to identify mesothelioma, and the authors first suspected lymphohistiocytoid mesothelioma. A wider panel of stains showed the cells were negative for other mesothelial markers. The authors identified the tumor as a blood-cell cancer consistent with myeloid sarcoma with monocytic differentiation or a blastic plasmacytoid dendritic cell neoplasm. Most findings favored myeloid sarcoma, although one marker (SPIB) is typical of the other diagnosis. The authors concluded that the tumor's location and this staining pattern can lead to a mistaken diagnosis of mesothelioma. The article does not mention asbestos.

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 (letter to the editor) of one patient
• Who was studied: One 60-year-old man with constitutional symptoms, shortness of breath and pleural effusion
• Main results:
  • Imaging showed an 11 cm mass in the left lung, with a large left pleural effusion, pleural implants and enlarged mediastinal lymph nodes
  • The patient had an aggressive course and died 4 months after symptoms began, without a diagnosis or treatment
  • On the initial stains, the tumor cells (both epithelioid and spindle cells) were positive for HBME-1 and D2-40 (podoplanin)
  • The authors' initial suspicion was lymphohistiocytoid mesothelioma
  • On additional, more extensive staining, the tumor cells were negative for other mesothelial markers
  • The additional staining confirmed a blood-cell (hematologic) cancer, consistent with myeloid sarcoma with monocytic differentiation or blastic plasmacytoid dendritic cell neoplasm
  • Staining for lysozyme, CD68, CD14 and CD163, and absence of TCL1 and CD303, was more in favor of myeloid sarcoma with monocytic differentiation
  • Expression of SPIB in this case was typical of blastic plasmacytoid dendritic cell neoplasm
  • Within the tumor there was a proliferation of T lymphoblasts that stained for TDT
• The authors' conclusion: The authors concluded that HBME1 and podoplanin staining in this myeloid sarcoma of the pleura, lung and mediastinum, with lymphoblasts inside the tumor, can lead to a mistaken diagnosis of lymphohistiocytoid mesothelioma. In their view the initial diagnosis was driven by the tumor's location and the use of a narrow panel of antibodies.
• Limitations the authors state:
  • No bone marrow biopsy was performed
  • IgH and TCR rearrangement and genetic studies were not performed, so the authors could not rule out that the T lymphoblast infiltrate was itself tumor or part of a mixed-phenotype acute leukemia

Topics

Medical terms in this study, explained in our Lexicon: Sarcoma, Podoplanin (D2-40).

Related studies

• Expression of podoplanin and calretinin in meningioma: an immunohistochemical study — M. Shintaku, T. Honda, et al. (2010)
• Value of podoplanin as an immunohistochemical marker in tumor diagnosis: a review and update — N.G. Ordóñez (2014)
• Podoplanin is a useful marker for identifying mesothelioma in malignant effusions — A. Hanna, Y. Pang, et al. (2010)
• Diffuse Pleural Myeloid Sarcoma Mimicking Malignant Mesothelioma — A. Dong, C. Bai, et al. (2016)
• Combined use of novel epithelial (MOC-31) and mesothelial (HBME-1) immunohistochemical markers for optimal first line diagnostic distinction between mesothelioma and metastatic carcinoma in pleura — C. González-Lois, C. Ballestín, et al. (2001)
• Podoplanin promotes progression of malignant pleural mesothelioma by regulating motility and focus formation — S. Takeuchi, K. Fukuda, et al. (2017)

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