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: welldifferentiated 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: Our report demonstrates the unique capability of mediastinal GCTs to simultaneously develop two different SMs.The presence of two different SMs in mediastinal GCTs is associated with extremely aggressive behavior and a poor prognosis.
Zheng et al. (Fri,) studied this question.