History: An otherwise healthy young man presents with discomfort.
病史：青年男性，原本健康，现身体不适。
Chest radiographs and CT images are shown below.
胸部平片及CT图像如下所示。
Findings
Initial chest radiographs demonstrate a large anterior mediastinal mass, which on CT is shown to be a soft-tissue mass,which is encasing vessels and severely compressing the superior vena cava (SVC). On follow-up chest CT, a hypervascular lesion is seen within the left lobe of the liver with a direct connection to the venous collaterals associated with SVC obstruction.
胸片示一巨大前纵隔肿物，在CT上表现为软组织肿块，包绕血管并明显压迫上腔静脉。肝左叶可见一富血供病变，其直接与静脉侧支相连，与上腔静脉闭塞有关。
Differential diagnosis
Anterior mediastinal mass in a young man
- Lymphoma
- Germ cell tumor
- Thymoma, thymic carcinoid or thymic carcinoma
- Thyroid goiter
Hypervascular liver lesion
- Vascular shunting
- Hypervascular metastasis
- Primary hypervascular liver tumor such as focal nodular hyperplasia, adenoma, or hepatocellular carcinoma
鉴别诊断
青年男性前纵隔肿物：
- 淋巴瘤
- 生殖细胞瘤
- 胸腺瘤、胸腺类癌或胸腺癌
- 甲状腺肿
肝脏富血供病变：
- 血管分流
- 富血供转移瘤
- 原发性肝脏富血供肿瘤（FNH、腺瘤、肝细胞癌）
Diagnosis:
Anterior mediastinal germ cell tumor
The hypervascular left lobe liverlesion is a “pseudolesion” caused by shunting through inferiorepigastric venous collateral running through the liver secondary to SVCobstruction.
最后诊断：前纵隔生殖细胞瘤
肝左叶富血供病变是一个“假性病变”，是由上腔静脉闭塞所致的腹壁下静脉穿行于肝脏形成的血管分流。
Key points
Mediastinal germ cell tumors
- Teratomas are the most common mediastinal germ cell tumor (70%); seminomatous and nonseminomatous tumors are less common.
- Teratomas are divided into mature and immature subgroups.
- Teratomas are often multicystic and commonly contain fat and/or calcification.
- Seminomas are typically homogeneous and calcification is rare.
- Nonseminomatous germ cell tumors are often ill-defined with regions of necrosis.
前纵隔生殖细胞瘤
- 畸胎瘤是最常见的前纵隔生殖细胞瘤（70%），精原细胞瘤和非精原细胞瘤相对少见。
- 畸胎瘤可分为成熟型和不成熟型。
- 畸胎瘤通常是多囊性，常包含脂肪和/或钙化。
- 精原细胞瘤典型表现为病变密度均匀，钙化罕见；
- 非精原细胞型生殖细胞瘤常表现病变边界不清，内可见坏死区。
Hypervascularliver lesions
Arterial-phase imaging through theliver in a patient with SVC obstruction can produce hypervascular”pseudolesions” in the left liver lobe via collaterals involvinginferior epigastric veins that course through the liver.
富血供肝脏病变
上腔静脉梗阻的患者增强扫描动脉期在肝左叶可见富血供的“假性病变”，可见与腹壁下静脉间形成的侧支循环穿过肝实质。
知识点图解
