Development of angiosarcoma in a mediastinal non-seminomatous germ cell tumor that exhibited growing teratoma syndrome during chemotherapy

Abstract

Herein, we report a case of an angiosarcoma in a mediastinal non-seminomatous germ cell tumor that exhibited growing teratoma syndrome during chemotherapy. A 26-year-old man presented with a giant anterior mediastinal mass, which was diagnosed as a non-seminomatous germ cell tumor. The patient was administered three cycles of chemotherapy (bleomycin, etoposide, and cisplatin), but the mass grew despite normalization of tumor markers. Massive bleeding during thoracic surgery resulted in incomplete resection, and the mass was clinically and pathologically diagnosed as growing teratoma syndrome (only mature teratoma). The residual mass continued to grow, and complete resection was subsequently achieved after a detailed analysis of its vascular anatomy using angiography. The final pathological findings revealed angiosarcoma, which indicated a rare somatic type of mediastinal non-seminomatous germ cell tumor.

Keywords: BEP chemotherapy; germ cell tumor; sarcoma; somatic type.

Figure 1

(a) Contrast‐enhanced computed tomography (CT) before chemotherapy reveals a large anterior mediastinal mass (arrow) and right pleural effusion (arrowhead). (b) Contrast‐enhanced CT after three cycles of chemotherapy revealed that the mass had grown to approximately 14 × 10 cm, with high vascularity in the anterior mediastinum (arrow). (c) T2‐weighted magnetic resonance imaging (MRI) reveals a heterogeneous high signal intensity area and high signal intensity nodules in the tumor (arrow). (d) Positron emission tomography‐CT revealing mixed spots of mild, moderate, and severe accumulation of fluorine‐18 fluorodeoxyglucose in the tumor. The maximum standardized uptake value was 5.3. (e) Contrast‐enhanced CT three months after the initial surgery shows the residual mass in the anterior mediastinum (arrow). (f) Contrast‐enhanced CT six months after the initial surgery reveals regrowth of the residual mass in the anterior mediastinum (arrow). (g) Right pleural effusion on CT and resected residual mass. (h) Multiple high signal intensity areas in the spine on sagittal T2‐weighted MRI. Ao, Aorta; LPA, left pulmonary artery; RPA, right pulmonary artery; SVC, superior vena cava.

Figure 2

Hematoxylin and eosin staining showing cystic lesions lined with mature epithelial cells, which consisted of bronchial mucosa and glands, as well as gastrointestinal mucosa with hemorrhagic and necrotic tissues but no malignancy.

Figure 3

(a) Coronary angiography showing collateral artery supply to the residual mass (arrow). (b) Computed tomography (CT) angiography showing that the left internal thoracic artery and arterial branches were supplying the residual mass (arrow). (c) CT angiography showing an arterial branch of the left internal thoracic artery, which appeared to supply the right ventricle (arrow).

Figure 4

(a) Hematoxylin and eosin staining showing that the tumor consisted of atypical spindle and pleomorphic cells. (b–d) Immunohistochemical examination shows that tumor cells were (b) negative for AE1/AE3 and (c) epithelial membrane antigen, (d) but expressed CD31.