小儿骶尾部生殖细胞源性肿瘤的CT和MRI诊断

目的：认识小儿骶尾部生殖细胞源性肿瘤的CT和MRI表现。材料和方法：对35例经手术病理证实的骶尾部畸胎瘤和卵黄囊瘤的CT和MRI检查资料进行回顾性分析。结果：35例骶尾部肿瘤中,29例畸胎瘤,6例为卵黄囊瘤。29例畸胎瘤内可见有脂肪、钙化和软组织成分;增强后软组织成分可见轻度强化。6例卵黄囊瘤中,1例肿瘤呈囊实性,边缘可见钙化;5例肿瘤呈不均匀软组织块,瘤内见出血,增强后均呈非均匀性强化。6例卵黄囊瘤甲胎蛋白检查阳性。结论：畸胎瘤和卵黄囊瘤是小儿骶尾部最常见生殖细胞源性肿瘤,含三个胚层成分是畸胎瘤的特征,而卵黄囊瘤多为软组织性肿瘤,好发生出血,能够分泌甲胎蛋白是卵黄囊瘤的特征。     

Computed tomography and magnetic resonance imaging of mediastinal tumors

We describe the clinical, pathological, and imaging findings of mediastinal tumors with focus on thymic hyperplasia, thymic epithelial tumors, and germ cell tumors, malignant lymphoma, and various cystic masses. Chemical shift magnetic resonance imaging (MRI) is useful in characterization of the normal thymus and differentiation of hyperplastic thymus and thymic tumors. In contrast to noninvasive thymomas, invasive thymomas and thymic carcinomas show a more aggressive growth pattern. Local invasion and pleural spread are characteristic of invasive thymoma and mediastinal lymphadenopathy and distant metastasis suggest thymic carcinomas. Mature teratoma typically shows various computed tomography (CT) attenuation, and MR signal intensity depending on its contents and fat tissue and bone within the lesions are its characteristic findings. Seminomas typically have homogenous internal CT attenuation and MR signal intensity with minimal contrast enhancement. Nonseminomatous malignant germ cell tumors characteristically show prominent internal degenerative changes and invasion to the adjacent structures. In mediastinal lymphomas, a residual mass is common after treatment and MRI provides important information in distinguishing viable tumors from residual benign masses. Some mediastinal cysts may reveal high attenuation similar to solid lesions on CT depending on their contents and MRI can be useful in the differentiation of cystic masses from solid lesions.     

CT and MR imaging of ovarian tumors with emphasis on differential diagnosis.

Ovarian tumors are classified on the basis of tumor origin as epithelial tumors (serous and mucinous tumors, endometrioid and clear cell carcinomas, Brenner tumor), germ cell tumors (mature and immature teratomas, dysgerminoma, endodermal sinus tumor, embryonal carcinoma), sex cord-stromal tumors (fibrothecoma; granulosa cell, sclerosing stromal, and Sertoli-Leydig cell tumors), and metastatic tumors. Epithelial tumors are primarily cystic and, when malignant, are associated with varying proportions of a solid component. Papillary projections are a distinctive feature of epithelial tumors. Profuse papillary projections are highly suggestive of borderline (low-malignant-potential) or malignant tumor. Ovarian teratomas demonstrate lipid material at computed tomography and magnetic resonance (MR) imaging. Malignant germ cell tumors manifest as a large, complex abdominal mass that contains both solid and cystic components. Tumor markers are helpful in diagnosis. The radiologic appearance of sex cord-stromal tumors varies from small solid masses to large multicystic masses. Granulosa cell tumors are usually large multicystic masses with solid components. Fibrothecoma, sclerosing stromal tumor, and Sertoli-Leydig cell tumors are usually solid masses. Fibromas have very low signal intensity on T2-weighted MR images. Certain radiologic findings predominate for each type of tumor. Knowledge of these key features of ovarian tumors provides the criteria for making a specific diagnosis or substantially narrowing the differential diagnosis.     

CT and MR imaging in staging non-small cell bronchogenic carcinoma: report of the Radiologic Diagnostic Oncology Group.

The accuracies of magnetic resonance (MR) imaging and computed tomography (CT) in determining tumor classification and assessing mediastinal node metastases were compared in a prospective cooperative study of 170 patients with non-small cell bronchogenic carcinoma. The sensitivity of CT in distinguishing T3-T4 tumors from T0-T2 tumors was 63%; specificity was 84%. These values for MR imaging were not significantly different (56% and 80%). With receiver operating characteristic (ROC) analysis, no difference existed between the accuracies of CT and MR imaging in diagnosis of bronchial involvement or chest wall invasion, but MR imaging was significantly more accurate than CT (P = .047) in diagnosis of mediastinal invasion. Lymph node sampling was performed in 155 patients (642 node stations). Cancerous nodes were found in 14% of stations in 21% of patients. There was no significant difference between the accuracies of CT and MR imaging in detecting mediastinal node metastases (N2 or N3); the sensitivities were 52% and 48%, respectively, and specificities were 69% and 64%. ROC analysis also showed no difference between CT and MR imaging.     

Mature and immature ovarian teratomas: CT, US and MR imaging characteristics

Ovarian teratomas (OTs) are the most common germ cell neoplasm. They include mature cystic teratomas, monodermal teratomas (neural tumors, struma ovarii, carcinoid tumors) and immature teratomas. Teratomas are the most common benign ovarian neoplasms in women less than 45 years old. OTs are usually characterized by ultrasound (US) and magnetic resonance (MR) whereas they are usually an incidental finding on CT. The purpose of this paper is to review the most common types of teratomas and to describe CT, US and MR imaging features of the various types of mature and immature OTs.     

Common tumors of the parapharyngeal space: refined imaging diagnosis

Computed tomographic (CT) scans and magnetic resonance (MR) images in 103 patients with either a deep-lobe parotid tumor extending into the parapharyngeal space, a minor salivary gland tumor, a neuroma, or a paraganglioma were reviewed. The parotid or extraparotid nature of these masses was established by identifying a fat plane between the mass and the parotid gland. This was more reliably accomplished with MR imaging than with CT. Although dynamic CT allowed identification of the glomus tumors, MR imaging also permitted diagnosis of these lesions. The inherent CT and MR imaging characteristics of most of the neuromas and minor salivary gland tumors were indistinguishable. However, the neuromas tended to displace the internal carotid artery anteriorly, whereas the salivary lesions displaced this vessel posteriorly. This artery was better identified on MR images than on CT scans. Thus, these lesions, which are the four most common primary parapharyngeal space tumors, can be distinguished on MR images by evaluating not only their inherent signal characteristics but also the surrounding fat planes and any displacement of the internal carotid artery.     

骨小圆细胞肿瘤的影像学分析

目的探讨骨小圆细胞肿瘤(small round cell tumor of bone,SRCT)的影像学特征及鉴别诊断,旨在提高对该病的认识及诊断水平。方法回顾性分析28例经病理证实的SRCT的影像表现。13例行X线平片检查,19例行CT检查,17例行MRI检查。结果 28例中,淋巴瘤10例,尤文氏肉瘤6例,浆细胞肿瘤6例,原始神经外胚层肿瘤4例,小细胞型骨肉瘤1例,间充质软骨肉瘤1例。CT、MRI表现为不同程度的骨质破坏,多数破坏较轻,但灶周软组织肿块较大且大于骨侵犯范围。结论 SRCT既有类似的影像学表现,各自也有其影像学特征,综合临床,可做出初步诊断,确诊需病理、免疫组织化学检查。     

Giant malignant sacrococcygeal germ cell tumor in a newborn: A rare case report

Malignant germ cell tumors constitute about 3%-4% of all neoplasms occurring before the age of 15. They arise in the ovaries, the testes, and in several other locations, including the lower back, the chest, the brain, and the abdomen. In infants and young children, the sacrococcygeal region is the most common site for extragonadal germ cell tumors, and teratomas account for the vast majority of sacrococcygeal germ cell tumors. Neonatal sacrococcygeal teratomas are usually benign and rarely they may contain a malignant component that is predominantly a yolk sac tumor. In this article, we describe a rare case of a male newborn with a giant sacrococcygeal mixed germ cell tumor composed of grade 3 immature teratoma and malignant yolk sac elements.     

颅内神经元肿瘤的影像诊断

目的 探讨颅内神经元肿瘤的影像学表现,评价CT和MRI对该类肿瘤的诊断价值。方法 经手术不病理证实的神经元肿瘤10例,回顾分析其CT及MRI表现,结果 节细胞胶质瘤3例;中枢神经细胞瘤3例;胚胎发育不良性神经上上皮肿瘤（DNT）3例（7个病灶）,肿瘤外形呈脑回状或结节脑回状,2个局灶性者呈中度强化,其余无明显强化。多纤维组织性婴儿节细胞胶质瘤（DIG）1例,病灶囊变明显,可见钙化,肿瘤实体明显均匀强化,结论 部分神经元肿瘤CT及MRI表现具有一定的特征性,但仅造影像学表现作出诊断是困难的,须结合临床资料,可进一步提高该类肿瘤的诊断正确率。     

MR imaging of intraocular lesions--a comparison with CT]

Thirty-two intraocular lesions were studied with magnetic resonance (MR) imaging and computed tomography (CT). These lesions included retinoblastoma (n = 11), uveal melanoma (n = 6), metastatic choroidal tumor (n = 3), choroidal hemangioma (n = 2), retinochoroiditis (n = 6) and Coats' disease (n = 4). MR imaging was superior to CT in the depiction of intraocular masses and retinal detachment. Gd-DTPA enhanced MR imaging was more useful than contrast enhanced CT in evaluating the contrast enhancement of intraocular tumors. Differential diagnosis of intraocular tumors was difficult with both MR imaging and CT. Intratumoral calcification was noticed on CT in nine cases of retinoblastoma. It was concluded that MR imaging, including contrast enhancement study, is more useful than CT in the evaluation of intraocular lesions, except for calcification, and contrast enhanced CT may be unnecessary in the diagnosis of intraocular lesions.     

Lateral ventricular neoplasms of the brain: differential diagnosis based on clinical, CT, and MR findings

The differential diagnosis of lateral ventricular tumors was explored by retrospective analysis of 47 pathologically proved cases identified by CT and/or MR imaging. Third ventricular tumors adjacent to the foramen of Monro (e.g., colloid cysts) were excluded. Forty-six patients underwent CT, and eight had MR imaging. The most common neoplasms were choroid plexus papilloma (10 cases) and meningioma (nine cases). Other common neoplasms included subependymoma (six cases), subependymal giant cell astrocytoma (five cases), and metastasis/lymphoma (four cases). Important features for differential diagnosis included age of the patient, the tumor's location within the lateral ventricle, and density on CT before IV administration of contrast material. Fifty percent of the tumors were in the ventricular atrium. All intraventricular tumor types (except subependymoma) showed contrast enhancement. MR was most useful in evaluating tumor location, size, and extent, but it did not help in eliminating alternative diagnoses. On the basis of patients' ages, specific tumor location, and the appearance on CT scans or MR images, an algorithm for differential diagnosis of lateral ventricular tumors was developed.     

Lateral ventricular neoplasms of the brain: differential diagnosis based on clinical, CT, and MR findings

The differential diagnosis of lateral ventricular tumors was explored by retrospective analysis of 47 pathologically proved cases identified by CT and/or MR imaging. Third ventricular tumors adjacent to the foramen of Monro (e.g., colloid cysts) were excluded. Forty-six patients underwent CT, and eight had MR imaging. The most common neoplasms were choroid plexus papilloma (10 cases) and meningioma (nine cases). Other common neoplasms included subependymoma (six cases), subependymal giant cell astrocytoma (five cases), and metastasis/lymphoma (four cases). Important features for differential diagnosis included age of the patient, the tumor's location within the lateral ventricle, and density on CT before IV administration of contrast material. Fifty percent of the tumors were in the ventricular atrium. All intraventricular tumor types (except subependymoma) showed contrast enhancement. MR was most useful in evaluating tumor location, size, and extent, but it did not help in eliminating alternative diagnoses. On the basis of patients' ages, specific tumor location, and the appearance on CT scans or MR images, an algorithm for differential diagnosis of lateral ventricular tumors was developed.     

Neurogenic tumors in the abdomen: tumor types and imaging characteristics.

There is a broad spectrum of neurogenic tumors that involve the abdomen. These tumors can be classified as those of (a) ganglion cell origin (ganglioneuromas, ganglioneuroblastomas, neuroblastomas), (b) paraganglionic system origin (pheochromocytomas, paragangliomas), and (c) nerve sheath origin (neurilemmomas, neurofibromas, neurofibromatosis, malignant nerve sheath tumors). Abdominal neurogenic tumors are most commonly located in the retroperitoneum, especially in the paraspinal areas and adrenal glands. All of these tumors except neuroblastomas and ganglioneuroblastomas are seen in adult patients. Abdominal neurogenic tumor commonly manifests radiologically as a well-defined, smooth or lobulated mass. Calcification may be seen in all types of neurogenic tumors. The diagnosis of abdominal neurogenic tumor is suggested by the imaging appearance of the lesion, including its location, shape, and internal architecture. Benign and malignant neurogenic tumors are difficult to differentiate unless distant metastatic foci are seen. For malignant tumors, imaging modalities other than computed tomography (CT) and magnetic resonance (MR) imaging may be necessary for staging. However, because most neurogenic tumors in adults are benign, CT and MR imaging can be used to develop a differential diagnosis and help determine the immediate local extent of tumor. Copyright RSNA, 2003.     

Imaging findings of CNS atypical teratoid/rhabdoid tumors

Four patients with brain tumors were diagnosed with atypical teratoid/rhabdoid tumors and underwent CT and MR imaging. For all tumors, aggressive features were shown by imaging studies and included hydrocephalus, apparent invasion of the adjacent brain and dura, and marked mass effect. The striking heterogeneity of the atypical teratoid/rhabdoid tumor shown by imaging studies reflects the histopathologic complexity of these tumors, and awareness of atypical teratoid/rhabdoid tumor is important in making the correct diagnosis of this uncommon but probably underdiagnosed entity.     

Sacrococcygeal chordoma: MR imaging in 30 patients

Objective To evaluate MR imaging of sacrococcygeal chordoma.Design and patients Thirty patients (age range 22–80 years) underwent MR imaging for the diagnosis and preoperative evaluation of sacrococcygeal chordomas. Eight patients had follow-up MR examination after treatment. The MR images were performed with T1- and T2-weighted imaging, and gadolinium (Gd)-enhanced imaging. The MR images were analyzed for the signal intensity, enhancing pattern, tumor size, growth pattern of the soft tissue component, and tumor extension.Results and conclusions T1-weighted images showed low signal masses with foci of high signal intensity in 73% of cases. Tumors enhanced in a variety of patterns after the administration of Gd. Soft tissue masses extending anteriorly were seen in all cases with posterior extension in 77% of cases. The posterior masses involved the surrounding muscles and extended toward the greater sciatic notch, appearing with pseudopodia (87%). Sacroiliac joints were involved in 23% of cases. Four lesions showed intraspinal extension and involvement of the posterior spinal muscles above the level of bony involvement. In 6 patients recurrent tumors were found at or around the surgical margin of the tumor 6 months to 5 years after resection of the sacral tumor. In two of the patients, nodular metastases to the pelvic bones and femur were found 1–4 years after initial examination. In conclusion, MR imaging is useful in the diagnosis and preoperative assessment of sacrococcygeal chordoma. Characteristic findings included sacral mass with heterogeneously high signal intensity with crisscrossing septa on long-repetition-time imaging, well-encapsulated pseudopodia-like or lobulated appearance, and gluteal muscle infiltration. Follow-up MR imaging is helpful to assess for recurrent or metastatic lesions of chordomas.This paper was presented at the International Skeletal Society 27th Annual meeting, Barcelona, Spain, August 2000.     

CT and MR imaging of fourth ventricular meningiomas

True fourth ventricular meningiomas are rare. We report two cases, one with typical CT, angiographic, and magnetic resonance (MR) appearances and one with atypical features of central cyst formation on CT and MR. The utility of MR in demonstrating intraventricular location in three imaging planes is illustrated. Given the rarity of these tumors, atypical features may preclude accurate preoperative diagnosis, even with MR.     

Pretreatment Diagnosis of Suprasellar Papillary Craniopharyngioma and Germ Cell Tumors of Adult Patients

BACKGROUND AND PURPOSE:Suprasellar papillary craniopharyngiomas and germ cell tumors in adults share some clinical and imaging similarities but have different therapeutic strategies and outcomes. This study aimed to evaluate the pretreatment diagnosis of these 2 tumors to improve the therapeutic outcome.MATERIALS AND METHODS:We retrospectively enrolled 18 adults with papillary craniopharyngiomas and 17 with germ cell tumors. The MR imaging findings were evaluated, including signal change and anatomic extension. The medical records were reviewed to collect clinical findings, management, and outcomes.RESULTS:The clinical findings of papillary craniopharyngiomas versus germ cell tumors were as follows: age: 46 ± 13.9 years versus 23 ± 7.1 years (P < .0001); diabetes insipidus: 2/18 (11%) versus 11/17 (65%) (P = .001); recurrence 13/16 (81%) versus 4/17 (24%) (P = .0031). The MR imaging findings of papillary craniopharyngiomas versus germ cell tumors were as follows—pituitary stalk thickening: 1.6 ± 0.4 mm versus 5.4 ± 4.2 mm (P < .0001); vertical infundibular extension: 1/18 (6%) versus 16/17 (94%) (P < .0001); sagittal spheric shape: 17/18 (94%) versus 1/17 (6%) (P < .0001); diffusion restriction: 1/17 (6%) versus 8/12 (67%) (P = .0009).CONCLUSIONS:Younger age, diabetes insipidus, MR imaging characteristics of restricted diffusion, and vertical infundibular extension favor the diagnosis of germ cell tumors. Spheric shape without infundibular infiltration provides clues to papillary craniopharyngiomas, which originate from the pars tuberalis and are located outside the third ventricle. We suggest that suprasellar germ cell tumor is possibly an intraventricular lesion. Appropriate treatment planning can be initiated according to the diagnosis and anatomic location.

Except for pituitary macroadenoma, suprasellar tumors are infrequent in adult patients. Some of these suprasellar tumors have specific clinical and imaging features that make them straightforward to diagnose and subsequently manage. These classic features include a dural tail appearance in meningioma; young age; cysts and calcifications in adamantinomatous craniopharyngioma; homogeneous infiltrating mass of hypothalamic/optic pathway gliomas; a midline enhancing lesion in germ cell tumor (GCT); specific locations with signal similar to those of gray matter in hamartoma; and bright signals on DWI in epidermoids.^1–3 However, some suprasellar tumors in adults can mimic each other in some clinical and imaging features, making pretreatment planning difficult.Papillary craniopharyngiomas (PCPs) and GCTs are 2 unusual suprasellar tumors in adults, with similar clinical and imaging findings in some aspects. Clinically, PCPs and GCTs mostly occur in young adults with visual impairment or pituitary axis dysfunction or diabetes insipidus. They commonly present as predominantly solid or mixed cysts and solid suprasellar lesions with contrast enhancement on MR imaging. However, the treatment and outcomes of both tumor types are quite different.^2,4,5 Surgical resection not only is the main treatment of PCPs but also remarkably affects the outcome.⁶ By contrast, complete surgical resection is usually unnecessary in patients with germinoma. This radiosensitive tumor can be well-controlled by radiation therapy alone or combined with chemotherapy, even without a tissue diagnosis.⁷ The preoperative diagnosis of these 2 unusual suprasellar tumors in adults facilitates appropriate treatment planning and avoids associated surgical morbidity. We presumed that the distinct embryology and pathogenesis of the 2 tumors develop unique clinical and MR imaging characteristics. This study was designed to evaluate retrospectively the clinical and MR imaging findings of suprasellar papillary craniopharyngioma and germ cell tumors in adult patients, to obtain a pretreatment diagnosis.     

脊索瘤的影像学特点分析

目的探讨脊索瘤的影像学表现。方法搜集经手术病理证实的脊索瘤42例,对其影像学表现进行回顾性分析。结果颅底脊索瘤23例(54.8%),骶尾部脊索瘤18例(42.9%),外周脊索瘤1例(2.3%)。平片可见颅底及骶尾部溶骨性骨质破坏;CT扫描脊索瘤特征性地表现为斜坡和骶尾部膨胀性软组织肿块伴相应部位广泛溶骨性骨质破坏;MRI扫描对病变范围的显示优于CT。结论脊索瘤有较为典型的好发部位,MRI表现较具特征性。     

CT and MR imaging of intralabyrinthine schwannoma: report of two cases and review of the literature

Two cases of intralabyrinthine schwannoma were studied with computed tomography (CT) and magnetic resonance (MR) imaging. On CT scans, a soft-tissue mass was identified in the round window niche in both cases. Widening of the basilar turn of the cochlea and characteristic erosion of the promontory were noticed in one case. Preoperative MR imaging (performed in only one case) revealed a soft-tissue mass in the labyrnth, extending into the round window niche. Findings at CT and MR imaging are discussed, and a differential diagnosis is given. The literature is reviewed. The authors' findings suggest that CT and MR imaging may prove very valuable in the previously difficult preoperative diagnosis of these tumors. In the setting of progressive sensorineural hearing loss, atypical Meniere disease, or recurrent vertigo, the presence of a mass in the labyrinth or labyrinthine windows- delineated on CT or MR images, despite a normal internal auditory canal, cerebellopontine angle, or brain stem - is highly suggestive of intralabyrinthine schwannoma.