Primary malignant lymphoma of the maxillary sinus: CT and MRI

We reviewed the CT and MRI of seven patients with primary malignant lymphoma of the maxillary sinus to find if there are characteristic imaging findings suggestive of the disease. The images were analysed for appearance, size, signal, internal characteristics, extent of tumour, bone change and lymph node enlargement. In two patients, the tumour first presented with mucosal thickening. In the remaining five, the tumours were an expansile mass 4–6 cm in diameter at the time of detection. Although it was difficult to distinguish tumour from mucosa or obstructed fluid on CT, T2-weighted MRI enabled us to separate tumour from normal mucosa or fluid. In two patients, the tumours were heterogeneous. Calcification and haemorrhage were observed in one patient. Periantral soft-tissue infiltration was always present, even when tumour appeared as slight mucosal thickening. Posterior extension was seen in all patients. Permeative and lytic bone destruction accompanied most cases of periantral soft-tissue infiltration; mixed destruction and sclerosis was also observed. Mucosal thickening with periantral soft-tissue infiltration may suggest malignant lymphoma of the maxillary sinus in its early form. Various types of bone change may accompany the periantral soft-tissue infiltration. Received: 25 January 1999 Accepted: 21 July 1999     

CT and sonographic diagnosis of retained surgical sponge

Seven cases of pathologically proven retained surgical sponge were reviewed and classified into four types, depending on CT and US findings. Type I: CT shows a mass with tiny gas bubbles, and sonogram shows an echogenic area with strong posterior shadow. Type II: CT shows an irregular high density mass with no gas bubble, and sonogram shows an echogenic area with strong posterior shadow. Type III: CT shows a low density mass with irregular internal high density areas, and sonogram shows a cystic mass with zigzag internal components. Type IV: CT shows an elliptic high density mass with low density area internally. Judging from the experiment and operative findings, these patterns were decided by the number and status of the gauze, volume of the exudate and hematoma, and status of the granulation. The author concludes that these characteristic CT and US findings, together with a history of surgery, permit the correct diagnosis of retained surgical sponge.     

Imaging of chest wall disorders.

Pathologic processes that may involve the chest wall include congenital and developmental anomalies, inflammatory and infectious diseases, and soft-tissue and bone tumors. Many of these processes have characteristic radiologic appearances that allow definitive diagnosis. Sternal deformities can be visualized at radiography and their severity quantified with computed tomography (CT). In cervical rib, CT with multiplanar reconstruction may demonstrate relevant anatomic detail and the relationship between bone deformity and arterial compression. In Poland syndrome, radiography reveals an area of hyperlucency on the affected side, whereas CT demonstrates the absence of the greater pectoral muscle and clearly depicts associated musculoskeletal anomalies. Tuberculosis typically manifests at radiography and CT as osseous and cartilaginous destruction and soft-tissue masses with calcification and rim enhancement. Aspergillosis involving the chest wall manifests as pulmonary consolidations and permeative osteolytic changes of the rib and spine at CT and as an area of increased signal intensity at T2-weighted magnetic resonance (MR) imaging. Neurogenic tumors and hemangiomas also typically have high signal intensity at T2-weighted MR imaging. Apparent mass extension or unequivocal bone destruction seen at CT or MR imaging may indicate chest wall involvement by lymphoma. Radiologically, soft-tissue sarcomas typically appear as areas of soft-tissue density or attenuation, often associated with necrotic areas of low density or attenuation. At radiography, plasmacytoma typically manifests as well-defined, "punched-out" lytic lesions with associated extrapleural soft-tissue masses. Chondrosarcoma frequently appears as a large, lobulated excrescent mass arising from a rib with scattered flocculent calcifications characteristic of its cartilaginous mix. Familiarity with these radiologic features facilitates accurate diagnosis and optimal patient treatment.     

罕少见脑胚胎性肿瘤患者的临床病理特征及其影像表现

目的 探讨几种罕少见的脑胚胎性肿瘤的临床病理特征及影像表现.方法 回顾性分析10例罕少见的经手术病理证实为脑胚胎性肿瘤患者的临床病理特征及MRI、CT表现.结果10例中,幕上原始神经外胚层肿瘤6例,室管膜母细胞瘤2例,髓上皮瘤1例,非典型性畸胎样或横纹肌样瘤1例,其中,4例为婴幼儿和儿童.各肿瘤的病理组织学表现具有一定特征性,是确诊的依据.肿瘤均位于幕上,体积较大,形态多不规则,呈分叶状,信号、密度不均匀,坏死囊变多见;肿瘤实质CT平扫多旱稍高密度,MRI表现为T2WI呈等或较高信号,T1WI呈较低信号,增强扫描显著强化.结论罕少见脑胚胎性肿瘤患者的MRI、CT表现无明显特异性,结合临床及病理组织学特征对其进行全面认识了解十分必要.     

The significance of sinonasal radiodensities: ossification,calcification, or residual bone?

PURPOSETo determine whether very radiodense material within a sinonasal soft-tissue mass on CT can be differentiated as calcification, ossification, or residual bone.METHODSWe retrospectively described the radiodensities within 235 sinonasal soft-tissue masses as discrete, solitary or multiple, or as a diffuse process with either a well-defined or poorly defined margin. They were also classified as calcification, ossification, or residual bone. Findings were correlated with pathologic specimens.RESULTSResidual bone was underdiagnosed; calcification was overdiagnosed. A solitary discrete density was most likely to be calcification within an inflammatory mass. However, multiple discrete densities were as likely to be in a tumor as in an inflammatory lesion. If the process was diffuse with a well-defined margin, it was most likely to be a benign fibroosseous lesion. If the process was diffuse with a poorly defined margin, it was most likely to be a high-grade sarcoma. Densities within inverted papillomas were shown to be residual bone, not calcifications; densities within esthesioneuroblastomas were calcifications.CONCLUSIONRadiodensities may help in refining a CT diagnosis, but one may not know based on CT whether the density is a calcification, ossification, or residual bone.     

Does Doppler analysis of musculoskeletal soft-tissue tumours help predict tumour malignancy?

AIM: To investigate whether analysing vascularity of soft-tissue tumours on ultrasound assists differentiating benign from malignant tumours. MATERIALS AND METHODS: One hundred and forty-eight vascular soft-tissue tumours in 148 patients (88 males, mean age 45.6 years) were studied. Final diagnosis was established histologically in 95 (64%) of cases. For each tumour, three-colour Doppler imaging features (vascularity, vascular density, vascular organization) and 13 pulsed Doppler (spectral analysis) parameters were assessed. Data analysis was performed to isolate optimal discriminatory criteria for differentiating benign from malignant tumours. RESULTS: Significantly more benign soft-tissue tumours had an organized vascular pattern on colour Doppler imaging. If the vascular pattern is organized, this is a good indicator of tumour benignity. However, this pattern was apparent in less then one-third of the soft-tissue tumours. Benign tumours also had significantly higher minimum end diastolic velocity (EDVmin) and lower mean ratio of resistive index (RImean) than malignant soft-tissue tumours, though considerable overlap existed between the two groups. CONCLUSION: Colour Doppler imaging analysis of soft-tissue tumours is of limited value when differentiating benign from malignant tumours. If an organized vascular pattern is present, the tumour is more likely to be benign. Flow characteristics were not specific enough to be applicable in clinical practice.     

Computed tomography of benign ovarian masses

Although ultrasound is the primary imaging modality for evaluating benign gynecologic pelvic masses, CT may provide diagnostic information regarding ovarian masses that are discovered fortuitously. The relatively infrequent use of CT in evaluating the adnexa has resulted in a paucity of literature regarding the CT characteristics of benign ovarian masses. The CT appearances of 24 benign ovarian masses are presented. Pathologic diagnoses were ovarian cyst (nine), endometrioma (five), teratoma (three), serous cystadenoma (two), mucinous cystadenoma (two), thecoma (one), cystadenofibroma (one), and Brenner tumor (one). Benign ovarian cysts have characteristic homogeneous water density and smooth walls on CT. Single internal septations and slight wall irregularity are also common features, but soft-tissue mural or septal nodules are uncommon. Computed tomography can be diagnostic in evaluating cystic teratomas. Other benign ovarian masses exhibit a spectrum of CT appearances that is often nonspecific, and surgical or biopsy proof may be necessary to exclude malignancy.     

Malignant germ cell tumours of undescended testes: imaging features with pathological correlation

AIM: To illustrate the imaging features of malignant germ cell tumours complicating undescended testes, emphasizing the importance of recognizing this condition and providing a correct diagnosis to facilitate appropriate management. METHODS: The clinical presentation, ultrasonography (US) and computed tomography (CT) features of eight consecutive patients with malignant germ cell tumours of undescended testes were reviewed. RESULTS: CT performed in seven patients showed well-circumscribed soft-tissue masses with inhomogeneous enhancement in all cases. US in four patients showed circumscribed masses with inhomogeneous echogenicity. On pathological examination, there were two cases of embryonal carcinoma and six cases of seminoma. All tumours showed necrosis that correlated to inhomogeneous areas on imaging. CONCLUSION: The radiologist has an important role as he may be the first physician to suggest the diagnosis.     

Bronchogenic cysts in the adult: diagnostic criteria derived from the correct use of standard radiography and computed tomography

PURPOSE: This study was undertaken to identify the radiographic and computed tomography patterns allowing a diagnosis of bronchogenic cyst. MATERIALS AND METHODS: We retrospectively reviewed chest radiographs and CT scans of 21 adults (ten men and 11 women, age range 18-74 years) with a histologically confirmed diagnosis of bronchogenic cyst. RESULTS: Sixteen cysts were located in the mediastinum and five in the lungs. On chest radiography, mediastinal cysts appeared as sharply marginated rounded areas of increased opacity; intrapulmonary cysts also exhibited an air-fluid interface. CT confirmed these morphological features in all cases. In addition, analysis of attenuation values allowed the subdivision of mediastinal cysts into three groups: fluid density (four cases), air density (two cases) and soft-tissue density (ten cases). CONCLUSIONS: All bronchogenic cysts were visualised on chest radiography, but the findings were nonspecific and required further characterisation by CT. The CT findings proved to be diagnostic when cystic attenuation values were evident. When soft-tissue attenuation values were demonstrated, a confident diagnosis was not possible, and other solid lesions had to be considered. In such cases, magnetic resonance imaging may be helpful to ascertain the cystic nature of the lesions.     

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.     

Myelolipoma of the adrenal: two cases with ultrasound and CT findings.

Myelolipoma of the adrenal gland is a rare tumor composed of varying proportions of fat and bone marrow elements. In about half of the reported cases with radiologic findings the mass was radiolucent, indicating the presence of fat; the remainder were of soft tissue density or calcified. Arteriography is of limited value in diagnosis, since myelolipomas are typically avascular. With the advent of gray scale ultrasound and computed tomography (CT), fat can be detected in lesions which do not appear radiolucent on radiographs. Two cases of myelolipoma are reported in which ultrasound showed a markedly echogenic mass, an appearance chracteristic of lipomatous tumors. In the second case, the mass was of soft tissue density on radiographs, markedly echogenic on sonogram, and definitively fatty on CT scan. Ultrasound and CT are valuable techniques for making a preoperative diagnosis of this tumor.     

Medulloblastoma in children: CT and MRI findings

Our purpose was to determine whether medulloblastoma (MB) shows specific neuroradiological features which may be employed in differential diagnosis from other common posterior cranial fossa tumours in childhood. Preoperative MRI was performed on 20 children with MB, and preoperative CT in 17 of them. All underwent surgery and histopathological diagnosis. There was a constant relationship between high density on CT and low signal on T1-weighted images. Signal behaviour on T2-weighted images and the degree of contrast enhancement were more variable. Most tumours arose in the midline, from the cerebellar vermis, involving the fourth ventricle, but hemisphere and extra-axial neoplasms were also seen. The combination of high density on CT and low signal on T1-weighted images is highly suggestive of MB and may assist preoperative differential diagnosis from other posterior cranial fossa tumours.     

颅底及面部骨纤维病变的影像学分析

目的 探讨颅底及面部骨纤维病变的CT和MRI诊断及鉴别诊断价值,提出术后影像学随访的重要性. 资料与方法回顾性分析经临床病理和组织学活检证实的颅底及面部20例骨化性纤维瘤和23例骨纤维发育不良患者的CT和MR影像学资料,并对两类病变共计27例进行术后影像随访.结果 20例骨化性纤维瘤中,18例为单骨发病,2例为多骨病变.CT表现为椭圆形或分叶状稍高密度肿块,边界清晰,瘤周有一层较完整或不完整的骨性包壳.内部呈不均匀密度13例,均匀磨玻璃样密度7例,其中11例有明显囊变坏死区;11例MR T_1WI以等、低信号为主,T_2WI以等、高信号为主,11例增强后间隔和实性部分强化.23例骨纤维发育不良中,多骨型20例,单骨型3例,无明确边界,密度均匀或不均匀,骨皮质变薄、模糊,骨质周围无软组织肿块和骨膜反应.5例MRT_1WI、T_2WI均以等、低信号为主,信号不均匀.结论 颅底及面部骨化性纤维瘤和骨纤维发育不良有相似的临床、病理特点,影像学有一定特征,有助于诊断和鉴别,部分病例两者鉴别困难.术后影像学随访以CT为主,MRI对需要再次手术者为重要补充.     

CT of soft-tissue neoplasms

The computed tomographic scans (CT) of 84 patients with untreated soft-tissue neoplasms were studied, 75 with primary and nine with secondary lesions. Each scan was evaluated using several criteria: homogeneity and density, presence and type of calcification, presence of bony destruction, involvement of multiple muscle groups, definition of adjacent fat, border definition, and vessel or nerve involvement. CT demonstrated the lesion in all 84 patients and showed excellent anatomic detail in 64 of the 75 patients with primary neoplasms. CT did not differentiate vessel or nerve entrapment from neurovascular structures that were simply applied to the pseudocapsule of the tumor. Blurring of adjacent fat was an infrequent finding, but when it was present, the tumor was malignant. The CT findings were characteristic enough to suggest the histology of the neoplasm in only 13 lesions (nine lipomas, three hemangiomas, one neurofibroma). No malignant neoplasm had CT characteristics specific enough to differentiate it from any other malignant tumor. However, malignant neoplasms could be differentiated from benign neoplasms in 88% of the cases.     

Computed tomography of hemangiomas and related soft-tissue lesions in children

The varied computed tomographic (CT) appearances of 19 hemangiomas and related soft-tissue lesions in 17 children were assessed retrospectively. Good CT-tissue correlation was obtained in 11 patients in whom histology was available. Although most cutaneous vascular lesions can be diagnosed by their characteristic clinical features, their extent may be difficult to assess clinically and at surgery. CT is important in defining the extent of these lesions as a guide for the surgeon, and for conservative follow-up. The often characteristic CT appearances also help in the diagnosis of the few patients with unusual clinical presentations.     

原发性纵隔囊肿的影像学表现

目的分析纵隔囊肿的影像学特点，提高对不同类型囊肿不典型表现的认识和诊断水平。方法回顾性分析经手术病理证实的44例纵隔囊肿的CT和（或）MRI资料（其中28和26例分别行CT和MR检查，10例同时行CT和MR检查），分析其影像学表现。结果囊肿位于前、中、后纵隔者分别为13、18和11例，位于前中纵隔者2例。支气管囊肿和心包囊肿位于不典型部位者分别为7和5例。CT密度近似于水者12例，占42．9％（12／28）。MR T2WI病变均为等或高于脑脊液的长T2信号，1例水成像上信号有衰减。近似于脑脊液的长T1信号者8例，占30．8％（8／26）。MRI信号不均匀者5例，原因各异。误诊14例。结论后纵隔和前纵隔CT高密度和厚壁的囊肿易被误诊为肿瘤性病变；中纵隔气管旁的心包囊肿易被误诊为支气管囊肿。MRI有助于诊断CT高密度的纵隔囊肿。MRI信号不均匀或水成像上信号衰减足误诊的原因。     

Soft-tissue abnormalities of the external auditory canal: subject review of CT findings

We review the normal anatomy and discuss characteristic findings of soft-tissue abnormalities of the external auditory canal (EAC). The indications for computed tomography (CT) of the temporal bone have been significantly expanded with the inclusion of soft-tissue abnormalities of the external ear and the auditory canal. Soft-tissue abnormalities of the EAC that can be evaluated with CT include atresia, edema, hemorrhage, fracture, posttraumatic or infection-caused keloid, malignant external otitis, hemangioma, lymphangioma, papilloma, keratosis obturans, acquired cholesteatoma, adenoma, ceruminoma, fibroma, mixed tumor, sarcoma, and basal cell, squamous cell, or adenocystic carcinoma. CT scans of 25 patients who had soft-tissue abnormalities of the EAC were reviewed. The clinical data were correlated with the radiographic findings. We conclude that CT is the best overall radiographic modality for evaluating the extent and character of soft-tissue abnormalities of the EAC. Significant clinical information that is helpful in patient management decisions is added by this technique.     

Size, shape, and appearance of the normal female pituitary gland

One hundred seven women 18-65 years old were studied who were referred for suspected central nervous system disease not related to the pituitary gland or hypothalamus. High-resolution, direct, coronal, contrast-enhanced computed tomography (CT) was used to examine the size, shape, and density of the normal pituitary gland. There were three major conclusions: (1) the height of the normal gland can be as much as 9 mm; (2) the superior margin of the gland may bulge in normal patients; and (3) both large size and convex contour appear to be associated with younger age. It was also found that serum prolactin levels do not appear to correlate with the CT appearances. Both low- and high-density areas were seen within the gland, and may be due to either tumors, cysts, infarcts, or metastases. Noise artifacts inherent in high-detail, thin-section, soft-tissue scanning may be a limiting factor in defining reproducible patterns in different parts of the normal pituitary gland.     

Evaluation of ectopic bone by CT

The CT appearance of ectopic bone and its maturation in 25 patients were correlated with the findings on radiographs and bone scans. Ossification progressed from an early appearance of soft-tissue density of lower attenuation than muscle to a calcific density paralleling radiographic and scintigraphic evidence of bone formation. Persistent unossified, low-density soft tissue was detected adjacent to mineralized areas of ectopic bone in 14 patients up to 16 years after neurologic injury, often with bone-scan evidence of maturity of the ectopic bone. This soft tissue most likely corresponds to immature, unossified connective tissue, which may have a potential for ossification. Detection of areas of soft-tissue density by CT and their avoidance during surgical resection of an ankylosing mass of ectopic bone may reduce intraoperative hemorrhage and postoperative ectopic bone recurrence.     

CT of benign soft-tissue masses of the extremities

The computed tomographic (CT) scans and medical records of 35 patients with proven benign soft-tissue masses of the extremities were reviewed to assess the contribution of CT in the evaluation of such masses. CT demonstrated the mass in all 35 cases and was able to provide a specific diagnosis in 28 (80%); 25 prospectively, three retrospectively. Correct diagnoses made using CT included hematomas (five), synovial cysts (seven), myositis ossificans (six), fatty tumors (four), aneurysms (three), pseudoaneurysms (two), schwannoma (one), and abscess (one). The CT appearance of a hematoma depends on its age. Synovial cysts are near-water-density masses, often associated with a small joint effusion. Myositis ossificans can be differentiated from parosteal osteosarcoma by virtue of its characteristic zonal ossification. Lipomas are recognized on noncontrast scans by the characteristic low attenuation of fat, while aneurysms and pseudoaneurysms are best diagnosed on postcontrast scans. In seven cases (20%) a specific diagnosis could not be made on the basis of the CT scan. However, in these cases CT delineated the extent of the mass and demonstrated its relation to surrounding structures; this anatomic information was helpful in planning surgical excision or percutaneous biopsy. The authors conclude that CT is a valuable noninvasive imaging method for the evaluation of soft-tissue masses of the extremities.