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Malignant Mesothelioma With EWSR1-ATF1 Fusion in Two Adolescent Male Patients
Hezhen Ren1, S Rod Rassekh2, Atilano Lacson3
1Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
Abstract:
Malignant mesothelioma is a neoplasm of serosal surfaces, most commonly affecting the pleura. The peritoneum, pericardium, and tunica vaginalis are less frequently involved. Malignant mesothelioma with EWSR1-ATF1 fusion in young adults was recently reported in the literature. Here, we present two pediatric cases of EWSR1-ATF1 translocation-associated malignant mesothelioma in the peritoneum and pericardium respectively. Both cases lacked a known exposure history. Microscopy in both cases showed predominantly epithelioid morphology with ample eosinophilic cytoplasm, and immunohistochemistry was positive for pan-keratin, calretinin, and WT1. Both cases showed EWSR1-ATF1 gene rearrangement by RNA sequencing, which was instrumental in confirming the diagnosis of malignant mesothelioma and to exclude more common pediatric sarcomas, especially in the context of limited sampling.
Insights
Pediatric malignant mesothelioma, a rare cancer, can be associated with the EWSR1-ATF1 gene fusion. This finding aids in diagnosing peritoneal and pericardial tumors in children, distinguishing them from other sarcomas.
Area of Science:
- Oncology
- Pediatric Pathology
- Molecular Diagnostics
Background:
- Malignant mesothelioma typically affects serosal surfaces, with pleural involvement being most common.
- While EWSR1-ATF1 fusion-associated mesothelioma has been noted in adults, its occurrence in pediatric patients is less documented.
- This specific genetic alteration presents a diagnostic challenge, particularly in younger populations.
Purpose of the Study:
- To report two pediatric cases of malignant mesothelioma associated with EWSR1-ATF1 translocation.
- To highlight the utility of molecular analysis in diagnosing rare pediatric neoplasms.
- To differentiate these rare mesotheliomas from common pediatric sarcomas.
Main Methods:
- Histopathological examination of tumor samples.
- Immunohistochemistry for pan-keratin, calretinin, and WT1.
- RNA sequencing to detect EWSR1-ATF1 gene rearrangement.
Main Results:
- Two pediatric patients presented with malignant mesothelioma of the peritoneum and pericardium, respectively.
- Both cases exhibited epithelioid morphology and positive immunohistochemical markers.
- RNA sequencing confirmed EWSR1-ATF1 gene rearrangement in both cases, crucial for diagnosis.
Conclusions:
- EWSR1-ATF1 translocation-associated malignant mesothelioma can occur in pediatric patients affecting the peritoneum and pericardium.
- Molecular confirmation of EWSR1-ATF1 fusion is vital for accurate diagnosis in pediatric cases.
- This genetic finding helps exclude other pediatric sarcomas, especially with limited tissue samples.
