Thymic epithelial tumors: comparison of CT and MR imaging findings of low-risk thymomas, high-risk thymomas, and thymic carcinomas

OBJECTIVE: To assess the CT and magnetic resonance (MR) imaging findings of thymic epithelial tumors classified according to the current World Health Organization (WHO) histologic classification and to determine useful findings in differentiating the main subtypes. MATERIALS AND METHODS: Sixty patients with thymic epithelial tumor who underwent both CT and MR imaging were reviewed retrospectively. All cases were classified according to the 2004 WHO classification. The following findings were assessed in each case on both CT and MRI: size of tumor, contour, perimeter of capsule; homogeneity, presence of septum, hemorrhage, necrotic or cystic component within tumor; presence of mediastinal lymphadenopathy, pleural effusion, and great vessel invasion. These imaging characteristics of 30 low-risk thymomas (4 type A, 12 type AB, and 14 type B1), 18 high-risk thymomas (11 type B2 and seven type B3), and 12 thymic carcinomas on CT and MR imaging were compared using the chi-square test. Comparison between CT and MR findings was performed by using McNemar test. RESULTS: On both CT and MR imaging, thymic carcinomas were more likely to have irregular contours (P < .001), necrotic or cystic component (P < .05), heterogeneous contrast-enhancement (P < .05), lymphadenopathy (P < .0001), and great vessel invasion (P < .001) than low-risk and high-risk thymomas. On MR imaging, the findings of almost complete capsule, septum, and homogenous enhancement were more commonly seen in low-risk thymomas than high-risk thymomas and thymic carcinomas (P < .05). MR imaging was superior to CT in the depiction of capsule, septum, or hemorrhage within tumor (all comparison, P < .05). CONCLUSION: The presence of irregular contour, necrotic or cystic component, heterogeneous enhancement, lymphadenopathy, and great vessel invasion on CT or MR imaging are strongly suggestive of thymic carcinomas. On MR imaging, the findings of contour, capsule, septum, and homogenous enhancement are helpful in distinguishing low-risk thymomas from high-risk thymomas and thymic carcinomas.     

胸腺瘤的CT诊断

目的评估CT诊断良恶性胸腺瘤的价值.材料和方法分析31例经外科和病理证实的胸腺瘤的CT表现.结果良性胸腺瘤10例,除1例与左肺动脉局部有粘连外,其余边界均清晰.侵袭性胸腺瘤12例,胸腺癌9例,除1例鳞癌外,CT均为不规则肿块,血管间隙均受侵,前者心包受侵8例,胸膜受侵7例,后者心包受侵5例,胸膜受侵5例,肺转移4例,双肾上腺转移1例,胸骨破坏1例.结论CT能准确鉴别良性恶性胸腺瘤,显示恶性胸腺瘤的浸润范围,并对侵袭性胸腺瘤和胸腺癌进行鉴别.     

MRI of anterior mediastinal tumors.

To compare the abilities of MRI (magnetic resonance imaging) and CT to provide information about anterior mediastinal tumors, we retrospectively evaluated the MR (n = 28) and CT images (n = 25) of patients with anterior mediastinal tumors. T1-weighted and T2-weighted images were obtained with spin echo sequences using cardiac gating. Six of 12 thymomas and seven of nine teratomas showed characteristic findings by MRI, while four of the 10 thymomas and five of the eight teratomas were correctly diagnosed by CT. The other tumors did not show a characteristic MR appearance. All nine malignant tumors were correctly diagnosed as malignant lesions on MR images, while one false positive case and one false negative case were recorded on CT images. We conclude that MRI and CT provide nearly the same information for the evaluation of anterior mediastinal tumors. However, in some cases, only MRI can provide information about malignancy or a specific diagnosis.     

Does CT of thymic epithelial tumors enable us to differentiate histologic subtypes and predict prognosis?

OBJECTIVE: The aims of our study were to describe the CT findings of thymic epithelial tumors and to correlate these findings with the histopathologic subtypes and prognosis. MATERIALS AND METHODS: The CT findings of thymic epithelial tumors were analyzed in 91 patients who had undergone surgery between May 1995 and June 2002. Two observers, who were unaware of the histopathologic classification made in accordance with World Health Organization (WHO) recommendations and the prognosis of the tumors, retrospectively reviewed the initial CT findings in terms of the contours and shapes of the tumors and the presence of necrosis, calcification, mediastinal fat or great vessel invasion, pleural seeding, contrast enhancement, and lymph node enlargement. These findings were compared with the simplified subgroups of WHO histologic classification (low-risk thymomas [types A, AB, and B1], high-risk thymomas [types B2 and B3], and thymic carcinomas [type C]) and with postoperative recurrence. RESULTS: The study found 31 low-risk thymomas (eight type A, 16 type AB, and seven type B1 tumors), 45 high-risk thymomas (25 type B2 and 20 type B3), and 15 thymic carcinomas (type C). Lobulated contour was more often seen in high-risk thymomas (26/45, 58%; p = 0.0456) and thymic carcinomas (10/15, 67%; p = 0.033) than in low-risk thymomas (9/31, 29%). Mediastinal fat invasion was more often seen in thymic carcinomas (5/15, 33%; p = 0.0133) than in low-risk thymomas (1/31, 3%). Great vessel invasion was seen only in thymic carcinomas (2/15, 13%; p = 0.0244). Tumors with a lobulated or irregular contour, an oval shape, mediastinal fat or great vessel invasion, and pleural seeding showed significantly more frequent recurrence and metastasis (all, p < 0.05). CONCLUSION: Although CT is of limited value in differentiating histologic subtypes according to the WHO classification, CT findings may serve as predictors of postoperative recurrence or metastasis for the thymic epithelial tumors.     

Cross-sectional imaging with CT and/or MRI of pediatric chest tumors

The purpose of this study was to provide an overview of the spectrum of pediatric chest masses, to present the results of cross-sectional imaging with CT and/or MRI, and to define diagnostic criteria to limit differential diagnosis. Seventy-eight children with thoracic mass lesions were retrospectively evaluated using CT (72 patients) and/or MR imaging (12 patients). All masses were evaluated for tissue characteristics (attenuation values or signal intensity, enhancement, and calcification) and were differentiated according to age, gender, location, and etiology. Twenty-eight of 38 (74 %) mediastinal masses were malignant (neuroblastoma, malignant lymphoma). Thirty of 38 (79 %) pulmonary masses were metastatic in origin, all with an already known primary tumor (osteosarcoma, Wilms tumor). With one exception, all remaining pulmonary lesions were benign. Seventeen of 21 (81 %) chest wall lesions were malignant (Ewing sarcoma, primitive neuroectodermal tumor). The majority of mediastinal and chest wall tumors in children is malignant. Lung lesions are usually benign, unless a known extrapulmonary tumor suggests pulmonary metastases. Cross-sectional imaging with CT and/or MRI allows narrowing of the differential diagnosis of pediatric chest masses substantially by defining the origin and tissue characteristics. Magnetic resonance imaging is preferred for posterior mediastinal lesions, whereas CT should be used for pulmonary lesions. For the residual locations both modalities are complementary. Received 7 March 1997; Revision received 9 September 1997; Accepted 14 November 1997     

儿童胸腺区恶性肿瘤的CT表现及其鉴别

目的分析儿童胸腺区恶性肿瘤的CT表现。资料与方法对8例经病理证实的儿童胸腺区恶性肿瘤的CT表现进行研究。结果8例均表现为胸腺区不均匀软组织密度肿块。3例侵袭性胸腺瘤，其中2例伴有胸腔积液，l例伴有肝脏转移。3例淋巴瘤胸腺浸润，均伴有其他部位淋巴结增大，l例伴有胸腔积液，2例伴有胸壁浸润以及椎管内侵犯l例。2例恶性生殖细胞瘤，其中l例恶性畸胎瘤肿块内见斑点状钙化灶，l例卵黄囊瘤伴有胸膜不规则增厚。结论CT检查能准确地显示出胸腺区恶性肿瘤的内部特征及其对邻近脏器的侵犯，因而对儿童胸腺区恶性肿瘤的诊断及鉴别诊断有较大价值。     

MSCT对胸腺上皮肿瘤WHO简化病理分型的鉴别诊断价值

目的探讨多层螺旋CT(MSCT)对低危型、高危型胸腺瘤及胸腺癌的鉴别诊断价值。方法回顾性分析经病理(穿刺或手术)证实的67例胸腺上皮肿瘤,基于WHO病理分型简化为低危型胸腺瘤、高危型胸腺瘤及胸腺癌三组,并对其CT征象进行统计分析。结果67例TETs中,低危型胸腺瘤30例(A型3例、AB型20例、B1型7例),高危型胸腺瘤22例(B2型11例、B3型11例),胸腺癌15例。高危型胸腺瘤、胸腺癌较低危型胸腺瘤易表现为边缘分叶或不规则(P均<0.05)及易出现对心包侵犯(P均<0.05);胸腺癌较低危型胸腺瘤易出现增强后密度不均、囊变坏死及胸膜转移(P均≤0.003);胸腺癌较低危型、高危型胸腺瘤易出现纵隔淋巴结肿大(P均≤0.002);纵隔大血管侵犯在三组间两两比较均有统计学差异(P均<0.05)。结论MSCT对TETs的WHO简化病理分型鉴别诊断具有重要价值。     

From the archives of the AFIP. Mediastinal germ cell tumors: radiologic and pathologic correlation.

Germ cell tumors occur most frequently in the gonad but can rarely occur in extragonadal locations, usually in or near the midline. The most common extragonadal site of primary germ cell tumors is the anterior mediastinum. The most common histologic type of mediastinal germ cell tumor is mature teratoma, which is typically asymptomatic and incidentally discovered. Radiographically, these tumors appear as rounded, often lobulated masses; calcification may be seen. Imaging studies of mature teratoma frequently demonstrate cystic components and may demonstrate fat or calcium. Malignant germ cell tumors usually occur as large masses in symptomatic young male patients. Seminomas are typically of homogeneous soft-tissue attenuation, and nonseminomatous malignant germ cell tumors are typically of heterogeneous attenuation on computed tomographic scans. Therapy varies according to cell type and may include surgery, radiation therapy, or chemotherapy. Prognosis is excellent for patients with mature teratoma, good for patients with pure seminoma, and poor for patients with nonseminomatous malignant germ cell tumors and mixed germ cell tumors.     

18F-FDG PET/CT of thymic epithelial tumors: usefulness for distinguishing and staging tumor subgroups.

The purpose of our study was to assess the usefulness of integrated PET/CT using 18F-FDG for distinguishing thymic epithelial tumors according to the World Health Organization (WHO) classification. METHODS: Thirty-three patients (age range, 34-68 y; mean age, 54.6 y) with thymic epithelial tumors, who underwent both integrated PET/CT and enhanced CT, were included. The clinicopathologic stages, maximum standardized uptake values (SUVs), and uptake patterns of tumors on integrated PET/CT images, and various enhanced CT findings, are described according to the simplified (low-risk [types A, AB, and B1] and high-risk [types B2 and B3] thymomas and thymic carcinomas) subgroups of the WHO classification. Discriminant analysis was performed to determine the relative capabilities of integrated PET/CT and enhanced CT findings to differentiate tumor subgroups. RESULTS: Tumors included 8 low-risk thymomas, 9 high-risk thymomas, and 16 thymic carcinomas. The maximum SUVs of high-risk thymomas (P < 0.001) and low-risk thymomas (P < 0.001) were found to be significantly lower than those of thymic carcinomas. Homogeneous 18F-FDG uptake within tumors was more frequently seen in thymic carcinomas than in high-risk thymomas (P = 0.027) or low-risk thymomas (P = 0.001). The uptake pattern (homogeneous vs. heterogeneous) on integrated PET/CT images and the presence of mediastinal fat invasion on enhanced CT images were found to be useful for differentiating tumor subgroups. In addition, integrated PET/CT helped detect lymph node metastases, which were not identified on enhanced CT in 2 patients. CONCLUSION: Integrated PET/CT was found to be useful for differentiating subgroups of thymic epithelial tumors and for staging the extent of the disease.     

胸腺瘤的CT和平片分析

目的　探讨胸腺瘤的X线与CT诊断价值。方法　分析 30例经手术病理证实的胸腺瘤X线和CT表现 ,并与病理对照。结果　 18例非侵袭性胸腺瘤 ,胸片仅发现 15例 ,CT扫描 10例 ,均为前纵隔软组织肿块 ,边界清楚 ,密度均匀。 12例侵袭性胸腺瘤 ,肿瘤侵犯邻近器官 ,CT显示纵隔胸膜受侵 3例 ,心包受侵 2例 ,大血管结构受侵 2例 ,胸膜种植 3例 ,胸腔积液 2例 ,腹腔受侵和纵隔淋巴结转移各 1例 ;胸片仅能显示 1例肿瘤侵犯纵隔胸膜和 1例胸膜种植。结论　CT扫描在胸腺瘤的发现和判别侵袭性方面明显优于X线平片并且是可靠预测胸腺瘤侵袭性的检查方法。     

Imaging findings of expansile lesions of the thymus

The purpose of this article is to review the imaging findings of the different expansile lesions of the thymus. Almost 50% of all mediastinal masses are located in the anterior mediastinum. The thymus is the most common site of origin of these masses. Several kinds of lesions can arise from this gland because it derives from the three embryonic germ cell layers. Primary neoplasms of the thymus are thymoma, thymolipomas, carcinoma, carcinoid, primary germ cell tumors, and lymphoma. The latter can also involve the organ in a secondary fashion. Other lesions that cause thymic enlargement and that can be confused with neoplasia are thymic cysts and thymic hyperplasia. Even though anterior mediastinal masses are first found on conventional radiographs, computed tomography and magnetic resonance are very useful additional studies for assessing the origin and extension of these masses. The basic concepts regarding embryology, anatomy, and histology relevant for the differential diagnosis of an enlarged thymic gland are also described.     

Thymoma: radiologic-pathologic correlation.

Thymoma is the most common primary neoplasm of the thymus. The majority of thymomas are encapsulated masses and exhibit a benign behavior. Less frequently, thymomas may be locally invasive, or rarely they may metastasize to distant sites. The usual clinical presentation is that of an anterior mediastinal mass found incidentally in an asymptomatic patient. The variable gross features of thymoma and the potential for local invasion result in a variety of radiologic appearances. The most common radiologic manifestation is a rounded, soft-tissue mass of the anterior superior mediastinum. Computed tomography and magnetic resonance imaging typically show a prevascular mediastinal mass of variable size and may be helpful in the evaluation of adjacent structures in cases of invasive thymoma. The treatment of choice is complete surgical excision. Radiation therapy and chemotherapy may be used adjunctively to surgery in the treatment of invasive tumors. The prognosis of encapsulated thymoma is generally favorable. Invasive tumors are associated with a worse prognosis but may respond to radical resection.     

纵隔低密度肿块病变的CT诊断

目的：提高纵隔低密度肿块病变的CT诊断水平。方法：回顾性分析52例经临床、手术及病理确诊的纵隔低密度肿块病例资料。结果：52例中皮样囊肿4例，畸胎瘤6例，胸腺囊肿3例，支气管囊肿5例，心包囊肿4例，脂肪瘤1例，胸内甲状腺肿囊变4例，胸腺瘤囊变5例，淋巴结肿囊变7例(淋巴瘤2例，淋巴结结核5例)，神经源性肿瘤囊变4例(神经节细胞瘤1例，神经鞘瘤2例，恶性神经纤维瘤1例)，纵隔血肿2例，纵隔脓肿6例。CT诊断正功率92．3％(48／52)。结论：纵隔低密度病变种类较多。CT检查可清楚显示病变的部位与特点，结合临床表现一般能作出准确的术前诊断。     

MSCT在鉴别≤3cm的低、高风险胸腺瘤及胸腺癌中的价值

目的 探讨多层螺旋CT(MSCT)对最大径≤3 cm的胸腺上皮肿瘤(TET)诊断价值.方法 回顾性分析56例经病理证实的最大径≤3 cm的TET病例的病理、影像学资料,根据WHO 2004标准进行组织学分型,将病例分为低风险胸腺瘤组(A/AB/B1型)、高风险胸腺瘤组(B2/B3型)、胸腺癌组(C型),分析各组TET的CT征象,包括病灶的形状、边缘是否光滑、是否伴有棘状突起、是否伴有瘤周小结节、强化程度、胸膜侵犯征象、周围脂肪间隙等.各类型间比较采用χ2检验,样本量过小时,采用Fisher精确试验.结果 低风险胸腺瘤(27例)较高风险胸腺瘤(23例)及胸腺癌(6例)更常表现为规则的类圆形的形态(χ2=73,P<0.001;χ2=116,P<0.001),纵隔-肺界面更易呈膨隆状(χ2=3.41,P=0.046;χ2=7.39,P=0.01);高风险胸腺瘤、胸腺癌较低风险胸腺瘤更常见边缘模糊、棘状突起、胸膜侵犯等征象(P<0.001);胸腺癌较高风险胸腺瘤更常见边缘模糊、棘状突起、胸膜侵犯等征象(χ2=11.5,P=0.009);B2型胸腺瘤与胸腺癌之间的差异有显著性意义(χ2=31.52,P<0.001),然而B3型胸腺瘤与胸腺癌之间无统计学差异(χ2=6.96,P=0.07).结论 MSCT可准确显示病灶的形态、边缘、瘤周情况、强化程度及胸膜侵犯情况,在一定程度上可预测胸腺瘤的组织学分型,可为术前诊断及预后评估提供依据.     

盆腔器官外软组织肿瘤的CT诊断

目的 探讨盆腔器官外软组织肿瘤的CT表现及其诊断价值。材料与方法 回顾性分析经手术病理证实的30例原发性盆腔器官外软组织良、恶性肿瘤的CT表现。其中间叶源性肿瘤15例,神经源性肿瘤8例,胚胎残余组织源性肿瘤5例,腹膜间皮细胞肿瘤2例。结果 原发于盆腔器官外软组织肿瘤较少见,CT表现为囊性肿块者均为良性,囊实性或实性者以恶性居多。虽然肿瘤来源于多种不同组织,但CT表现可各有其特征。结论 CT是诊断盆腔器官外肺瘤的重要影像学手段,能明确肿瘤范围以及肿瘤与周围组织的关系及其性质。     

Anterior mediastinal tumors: diagnostic accuracy of CT and MRI

Purpose

To compare the diagnostic accuracy for anterior mediastinal tumors among CT, MRI, and both CT and MRI, and to determine the optimal CT and MRI procedures for the diagnosis of anterior mediastinal tumors.

Materials and methods

Both CT and MRI were performed in 127 patients with pathologically diagnosed anterior mediastinal tumors. The patients included 48 cases of thymoma, 12 cases of thymic carcinoma, 12 cases of thymic cyst, 20 cases of mature teratoma, 13 cases of malignant germ cell tumor, and 22 cases of malignant lymphoma. The CT and MRI scans were assessed by two chest radiologists without knowledge of their clinical and pathologic data. The observers recorded various CT and MRI findings and their first choice of diagnosis.

Results

The two observers made a correct first-choice diagnosis in an average of 78 (61%) of 127 cases on CT, 71 (56%) of 127 cases on MRI, and 85.5 (67%) of 127 cases on both CT and MRI. These included 83% cases of thymoma on CT, 84% on MRI, and 85% on both CT and MRI; 38% cases of thymic carcinoma on CT and 13% on MRI, and 33% on both CT and MRI; 46% cases of thymic cyst on CT and 71% on MRI, and 63% on both CT and MRI; 58% cases of mature teratoma and 38% on MRI, and 78% on both CT and MRI; 35% cases of malignant germ cell tumor on CT and 27% on MRI, and 31% on both CT and MRI; and 55% cases of malignant lymphoma on CT and 43% on MRI, and 61% on both CT and MRI. There were significant differences between the diagnostic accuracy by CT and MRI in the cases with both thymic cysts and thymic carcinoma (p < 0.05).

Conclusion

CT is equal or superior to MRI in the diagnosis of anterior mediastinal tumors except for thymic cyst. CT should be considered the modality of choice following chest radiography, however, in certain circumstances, such as thymic cyst with hemorrhage or inflammation which mimic solid tumor despite low enhancement, MRI may be better in distinguishing anterior mediastinal tumors. For more helpful information in the diagnosis of mature teratoma after CT, MRI may follow.     

Thymic hyperplasia and thymus gland tumors: differentiation with chemical shift MR imaging

PURPOSE: To prospectively evaluate chemical shift magnetic resonance (MR) imaging for differentiating thymic hyperplasia from tumors of the thymus gland. MATERIALS AND METHODS: The institutional review board approved this study; informed consent was obtained and patient confidentiality was protected. The authors assessed 41 patients (17 male, 24 female; age range, 16-78 years) in whom thymic lesions were seen at chest computed tomography. Patients were assigned to a hyperplasia group (n=23) (18 patients with hyperplastic thymus associated with Graves disease and five with rebound thymic hyperplasia) and a tumor group (n=18) (seven patients with thymomas, four with invasive thymomas, five with thymic cancers, and two with malignant lymphomas). T2-weighted fast spin-echo and T1-weighted in-phase and opposed-phase MR images were obtained in all patients and visually assessed. A chemical shift ratio (CSR), determined by comparing the signal intensity of the thymus gland with that of the paraspinal muscle, was calculated for quantitative analysis. Mean CSRs for the patient groups and subgroups were analyzed by using Welch t and Newman-Keuls tests. P<.05 indicated a significant difference. RESULTS: The thymus gland had homogeneous signal intensity in all 23 patients in the hyperplasia group and in 12 of the 18 patients in the tumor group. The mean CSR (+/- standard deviation) was 0.614 +/- 0.130 in the hyperplasia group and 1.026 +/- 0.039 in the tumor group. Mean CSRs in the patients with a hyperplastic thymus and Graves disease, rebound thymic hyperplasia, thymoma, invasive thymoma, thymic cancer, and malignant lymphoma were 0.594 +/- 0.120, 0.688 +/- 0.154, 1.033 +/- 0.043, 1.036 +/- 0.040, 1.020 +/- 0.044, and 0.997 +/- 0.010, respectively. The difference in CSR between the hyperplasia and tumor groups was significant (P<.001). Mean CSRs in the hyperplasia subgroups were lower than those in the tumor subgroups (P<.001). All hyperplasia group patients had an apparent decrease in thymus gland signal intensity at chemical shift MR imaging; no tumor group patients had a decrease in thymus gland signal intensity. CONCLUSION: Chemical shift MR imaging can be used to differentiate thymic hyperplasia from thymic tumors.     

Diagnostic imaging of mediastinal masses in children.

Mediastinal masses are the most common thoracic masses in children. The encyclopedic list of diagnostic considerations can be distilled into a concise and practical differential diagnosis based on the location of the mass and the established prevalence of various tumors and pseudotumors in the mediastinal compartments. Malignant lymphoma, benign thymic enlargement, teratomas, foregut cysts, and neurogenic tumors make up 80% of mediastinal masses in children. Continuing advances in imaging technology have altered traditional approaches to the evaluation and diagnosis of mediastinal masses in children. Plain chest radiography remains the basic imaging examination to define location and morphology. Cross-sectional imaging subsequently clarifies the morphology and extent of the mass. In general, CT is the primary cross-sectional imaging procedure in the evaluation of most mediastinal masses in children. Exceptions to this rule include MR in children with posterior mediastinal masses or suspected vascular lesions: in such cases, MR imaging is the preferred initial postradiographic examination. Sonographic examination may be diagnostic in foregut cysts and some other mediastinal masses. Gallium-67 scintigraphy has an emerging role in management of malignant lymphoma.     

The thymus gland in computerized tomography. Normal findings and pathology

The diagnostic value of CT in follicular thymic hyperplasia and in thymomas in 8 patients with myasthenia gravis and in 12 patients without myasthenia gravis suffering from thymic tumors was evaluated by correlating CT-findings to surgical results and pathological-histological findings. Thymic size of the six patients with histologically proven follicular hyperplasia were scattered within the normal range, but half of them were at the upper limit. Thymic tumors were differentiated between invasive and non invasive tumors by CT staging. Solid tumors with different histology could not be further classified; the attenuation values ranging from 15-55 HU were the same in tumors, follicular hyperplasia and normal thymus.     

纵隔生殖细胞源性肿瘤的CT诊断和鉴别诊断(附32例报告)

目的总结纵隔生殖细胞源性肿瘤的CT表现及良、恶性的鉴别要点。方法回顾性分析32例经手术病理证实的纵隔生殖细胞源性肿瘤。结果32例中,良性生殖细胞源性肿瘤26例,其中囊性肿块10例,实性肿块9例,囊实性肿块7例;恶性生殖细胞源性肿瘤6例,其中精原细胞瘤、内胚窦(卵黄囊)瘤及胚胎细胞癌各1例和恶性畸胎瘤3例。典型的良性畸胎类肿瘤显示水样至软组织密度肿块,边缘清晰,其内有脂肪或钙化等,推移压迫周围组织,恶性肿瘤具有边缘分叶状或不规则,与周围组织脂肪间隙消失并侵犯相邻器官的征象。结论CT对纵隔良性生殖细胞源性肿瘤能准确作出诊断,纵隔恶性生殖细胞源性肿瘤难以与纵隔其它恶性肿瘤区分。