Two different somatic-type malignancies arising from a mediastinal germ cell tumor

Background

Mediastinal germ cell tumors (GCTs) are rare malignant neoplasms that occasionally develop somatic-type malignancies (SMs), such as sarcomas, carcinomas, and hematologic malignancies.

Case presentation

We report a unique case of a 16-year-old male patient with a mediastinal GCT that simultaneously developed two different SMs: well-differentiated angiosarcoma and acute megakaryoblastic leukemia (AML). The patient initially presented with left shoulder pain and intermittent shortness of breath. The imaging study demonstrated a 12.5 × 9.0 × 8.5 cm heterogeneous mass in the left anterior mediastinum. The mediastinal mass was resected and showed a cystic mature teratoma with somatic transformation into well-differentiated angiosarcoma and AML. A subsequent bone marrow biopsy confirmed the diagnosis of AML, and next-generation sequencing demonstrated the presence of PTEN and TP53 gene mutations in the AML. Despite aggressive chemotherapy and allogeneic stem cell transplantation, the patient died 10 months after diagnosis.

Conclusions

In the current report, we present a rare case of a 16-year-old male patient with mediastinal GCT that developed two different SMs: well-differentiated angiosarcoma and AML. The simultaneous development of angiosarcoma and AML in the same tumor suggests that they likely originate from the same pluripotent progenitor cells. The tumor showed a poor response to chemotherapy and allogeneic bone marrow transplantation, and the patient died approximately 10 months after diagnosis. Our study indicates that the presence of two different SMs in mediastinal GCT is associated with a dismal clinical outcome. Advanced molecular techniques can detect genetic alterations that underlie somatic transformation in mediastinal GCT and facilitate the exploration of targeted therapy.

Full text

https://www.xiahepublishing.com/2771-165X/JCTP-2025-00053

The study was recently published in the Journal of Clinical and Translational Pathology.

Journal of Clinical and Translational Pathology (JCTP) is the official scientific journal of the Chinese American Pathologists Association (CAPA). It publishes high quality peer-reviewed original research, reviews, perspectives, commentaries, and letters that are pertinent to clinical and translational pathology, including but not limited to anatomic pathology and clinical pathology. Basic scientific research on pathogenesis of diseases as well as application of pathology-related diagnostic techniques or methodologies also fit the scope of the JCTP.

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