Primary ectopic meningioma in the thoracic cavity: A rare case report and review of the literature

Our plain-English summary of Primary ectopic meningioma in the thoracic cavity: A rare case report and review of the literature, by X. Liu, J. Liu, T. Nai, et al (Frontiers in Oncology, 2023).

The study

• Authors: X. Liu, J. Liu, T. Nai, Y. Yang, Y. Hu
• Journal: Frontiers in Oncology
• Published: 2023;13:1149627
• Type of article: Case report
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Meningioma is a common type of intracranial tumor in adults. It rarely arises in the chest, with only a few case reports in the English literature. Here, we report the case of a patient with a primary ectopic meningioma (PEM) located in the thoracic cavity.

Case Presentation: A 55-year-old woman presented with exercise-induced asthma, chest tightness, intermittent dry cough and fatigue for several months. Computed tomography revealed the presence of a huge mass in the thoracic cavity, with no connection to the spinal canal. Lung cancer and mesothelioma were suspected, and surgery was performed. Grossly, the mass was a grayish-white solid 9.5 cm × 8.4 cm × 5.3 cm in size. The microscopic morphology of the lesion was consistent with that of typical central nervous system meningioma. The pathological subtype was transitional meningioma. The tumor cells were arranged in a fascicular, whorled, storiform and meningithelial pattern, with occasional intranuclear pseudo-inclusions and psammoma bodies. In focal areas tumor cells were considerably dense, and the cells were round or irregular in shape, with less cytoplasm, uniform nuclear chromatin, and visible nucleoli and mitoses (2/10 HPF). By immunohistochemistry, the neoplastic cells showed strong and diffuse staining with vimentin, epithelial membrane antigen and SSTR2 with variable expression of PR, ALK and S100 protein. However, the cells were negative for GFAP, SOX-10, inhibin, CD34, STAT6, smooth muscle actin, desmin, CKpan, D2-40, WT-1, CK5/6 and CD45. The highest proliferation index by Ki-67 was 15%. The abnormal expression of ALK led to the initial misdiagnosis of an inflammatory myofibroblastic tumor. After 12 months of follow-up, no disease progression was observed.

Conclusion: The presence of primary ectopic meningiomas in the thoracic cavity is extremely rare, and this tumor is easily misdiagnosed clinically. Imaging is suggested to determine the location and possible differential diagnosis, while the final diagnosis should be via pathological examination. Immunohistochemistry is crucial for disease diagnosis. Owing to our limited knowledge of PEM, its pathogenesis and tissue of origin remain unclear. Clinicians should pay close attention to such potential patients. The present case report may provide insights into the diagnosis and therapy of patients with this tumor.

Copyright © 2023 Liu, Liu, Nai, Yang and Hu.

In plain English

This article is a case report of one patient, a 55-year-old Asian woman treated in Yichang, China, with a primary ectopic meningioma. A meningioma is normally a tumor of the brain or spinal cord lining; this one was found outside the central nervous system. The patient had exercise-induced asthma, chest tightness, intermittent dry cough and fatigue. A chest CT scan showed a large mass in the left chest cavity. Doctors suspected mesothelioma or lung cancer, and the mass was removed by surgery. It measured 9.5 cm × 8.4 cm × 5.3 cm and was not attached to the spinal canal. Microscope and staining tests identified a transitional WHO grade 1 meningioma, and a head CT found no brain tumor. Staining for a protein called ALK first led to a wrong diagnosis of a different tumor type. No recurrence or spread was seen over 12 months of follow-up. The article does not mention asbestos. The authors concluded that surgery is the best treatment. They noted that they did not run genetic tests to check for an ALK gene fusion.

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 discussion that cites other published reports
• Who was studied: One 55-year-old Asian woman admitted to a hospital in Yichang, China (Yichang Central People's Hospital); report published 2023
• Exposure: No asbestos or other exposure was studied or mentioned. The article does not report the patient's occupational or asbestos history. Mesothelioma appears only as a suspected diagnosis that was ruled out.
• Main results:
  • Chest CT showed a large mass in the left thorax
  • At surgery, a 9-cm mass was found between the lung and the diaphragm, not attached to the spinal canal or dura
  • The removed mass measured 9.5 cm × 8.4 cm × 5.3 cm
  • Before pathology, the tumor in this patient was misdiagnosed as mesothelioma and lung cancer
  • The patient was diagnosed with primary ectopic meningioma in the left thoracic cavity, classified as transitional WHO grade 1 meningioma; the highest Ki-67 proliferation index was 15%
  • Abnormal ALK expression in the tumor led to an initial misdiagnosis of inflammatory myofibroblastic tumor
  • A head CT after diagnosis showed no central nervous system tumor
  • After 12 months of follow-up, no disease progression was observed in this patient
• The authors' conclusion: The authors concluded that primary ectopic meningioma in the thoracic cavity is rare and easily misdiagnosed. They wrote that central nervous system meningiomas must be excluded, that the final diagnosis should be confirmed by pathology, and that surgery is the best treatment option.
• Limitations the authors state:
  • The authors did not perform fluorescence in situ hybridization or next-generation sequencing to check for the ALK gene fusion suggested by staining

Topics

Medical terms in this study, explained in our Lexicon: Lung Cancer, Mesothelioma, Immunohistochemistry, Epithelial Membrane Antigen (EMA), CD34, Desmin, Podoplanin (D2-40), Wilms Tumor 1 (WT-1).

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