Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Mediastinal teratoma with malignant transformation
- Radiologic Findings
- Chest radiograph shows a mass in the left side of the anterior mediastinum.
Chest CT scans show a heterogeneously enhancing low-attenuated mass in left portion of the anterior medistinum. It contains fat component, calcified foci and enhancing tubular structure suggesting vascular structure.
Gross specimen of thymectomy presented as the anterior mediastinal mass. The cut surface shows a well-demarcated and ovoid firm mass containing focally solid, cystic, and chondroid components. Multiple foci of hemorrhage are noted. (Mature and immature teratoma with angiosarcomatous component.)
- Brief Review
- The most common histologic type of mediastinal germ cell tumor is mature teratoma, which occurs in young patients and usually occurs within or near the thymus gland and account for up to 75% of primary germ cell tumors of the mediastinum.
Benign teratomas are frequently discovered on routine chest radiography while the patient is asymptomatic.
Radiographically the typical appearance is that of a sharply demarcated, rounded or lobulated anterior mediastninal mass which projects beyond the mediastinal boundaries into adjacent lung fields. Radiographic evidence of calcification has been reported in approximated 20-43% of cases. It may represent calcification of the wall of the tumor, calcification in the tumor substance, ossification in mature bone, or calcification in a tooth or teeth within the tumor. Another specific sign for the diagnosis of teratoma is the presence of a fat-fluid level, which is seldom seen radiographically.
In this case, angiosarcomatous elements were intermingled with teratomatous elements and the patient's primary germ cell tumor contained malignant and atypical teratomatous elements as well as prominent vascular proliferation. Association of angiosarcoma with a germ cell tumor was reported several cases in English literature. Most of reported cases were testicular teratoma. Only one case was reported the development of angiosarcoma as a complication of mediastinal teratoma previously. Several explanations have been offered for the appearance of second malignancies. Among treatment-related causes, radiation-induced carcinogenesis has been well recognized for nearly a century. Sarcomas, in particular, are typical of being causally related to ionizing radiation. Although angiosarcoma is not commonly encountered among such sarcomas, its occurrence after radiotherapy is well documented, especially in the treatment of breast and cervical carcinomas. However, in some cases of GCT, it is unclear whether the mechanism of malignant transformation is de novo or therapeutically induced.
- References
- 1. Kathleen H. Muller, Mellssa L. Rasadi-de-Chrisenson, Philip A. Templeton. Mediastinal mature teratoma : imaging features. AJR 1997 ; 169 : 985-990
2. Saito A, Watanabe K, Kusakabe T, Abe M, Suzuki T. Mediastinal mature teratoma with coexistence of angiosarcoma, granulocytic sarcoma and a hematopoietic region in the tumor: a rare case of association between hematological malignancy and mediastinal germ cell tumor. Pathol Int. 1998;48(9):749-53
3. Sahoo S, Ryan CW, Recant WM, Yang XJ. Angiosarcoma masquerading as embryonal carcinoma in the metastasis from a mature testicular teratoma. Arch Pathol Lab Med. 2003;127(3):360-3
- Keywords
- Mediastinum, Malignant tumor,