Lipomatous lesions of the head and neck region: imaging findings in comparison with histological type

PURPOSE: Aim of the study is to demonstrate the main role of magnetic resonance imaging in the identification and characterization of lipomatous lesions of the head and neck. MATERIALS AND METHODS: CT and MRI findings of 78 patients (43 male, 35 female) aged 12-80 (mean 47.5) years surgically treated for lipomatous lesions of the head and neck region between January 1995 and June 2005 were retrospectively analysed and correlated with the histological results. RESULTS: On CT images, lipomas and fibrolipomas appeared as smooth (38/50 cases) or lobulated (12/50 cases) well-defined masses associated with moderate displacement of surrounding tissues; tumours had high signal intensity on MR T1-weighted images, with relative decreasing signal on T2-weighted images. Infiltrating lipomas appeared as expansile ill-defined masses with heterogeneous signal. Angiolipomas showed a characteristic contrast enhancement on both CT and MRI. In one case of sialolipoma, the lesion appeared markedly heterogeneous in signal. MR and CT images of Madelung's disease showed multiple symmetrical lipomatous masses involving the neck region. Intraosseous fatty lesions appeared as well-defined hypodense masses sometimes associated with cortical expansion and disruption. CONCLUSIONS: Both CT and MRI exams are useful for detecting lipomatous lesions. MRI, however, is more accurate in the evaluation of their extent and in the characterisation of uncommon lipomatous lesions of the head and neck, and intravenous administration of gadolinium better depicts the margins of the tumour and its vascularisation.     

Rhabdomyosarcoma of the petrous ridge. CT and MR imaging in an atypical case with multiple cranial nerve palsy.

The CT and MR findings are reported in a case of biopsy proven rhabdomyosarcoma of the skull base. The tumor presumably originated in a pneumatized petrous ridge and had an atypical presentation of multiple cranial nerve palsy. The lesion exhibited a soft tissue density and a nonexpansile bone destruction on unenhanced CT. On MR imaging the lesion showed homogeneous intermediate signal intensity on T1 weighted images and a high signal intensity on proton density and T2 weighted images. The scanty literature on CT and MR features of rhabdomyosarcoma of the head and neck is reviewed.     

Radiological findings in myxoid liposarcoma of the anterior mediastinum

CT and MR findings of a rare myxoid liposarcoma involving the anterior mediastinum are reported. The mass was a low density lesion with calcific septations and some peripheral frond-like enhancement on CT. MRI showed heterogeneous intermediate to high signal intensity on T1 weighted images and high signal intensity on T2 weighted images. The signal of the mass was not suppressed on fat suppressed images.     

MRI of chronic sclerosing sialoadenitis

The purpose of our study was to describe the MR appearance of Kuttner's tumours and to interpret their differences in appearance from other submandibular gland tumours. MR studies of 7 Kuttner's, 8 malignant and 12 benign submandibular gland tumours were reviewed. MR sequences obtained included T(1) weighted, short inversion time inversion recovery (STIR), T(2) weighted, diffusion-weighted (DW) and dynamic contrast-enhanced MR (dynamic MR) images. In all cases of Kuttner's tumour, the affected submandibular glands were swollen with slightly higher intensity on T(2) weighted, STIR and DW images, but the tumour margin could not be defined. Conversely, the margins of the other tumours could be detected. On T(2) weighted, STIR and DW images, the mean signal intensity ratios and the mean apparent diffusion coefficient (ADC) values for Kuttner's tumours and malignant tumours were significantly lower than those of benign tumours, but there were no significant differences between those of Kuttner's tumours and those of malignant tumours. All benign tumours showed late enhancement, with peak enhancement later than 120 s on dynamic MR images. Kuttner's tumours and malignant tumours showed variable enhancement patterns. In conclusion, signal intensity ratios for T(2) weighted and STIR images, ADC values and patterns of enhancement may help distinguish Kuttner's tumours from benign submandibular gland tumours, but not from malignant tumours. Although the intensities, ADC values and enhanced patterns of Kuttner's tumours were similar to those of malignant tumours, there were some morphological differences.     

Major salivary gland masses: comparison of MR imaging and CT

Computed tomography (CT) and magnetic resonance (MR) imaging studies were done prospectively in 21 unselected patients in whom 28 major salivary glands had pathologic changes. Blinded and final readings were used to establish the relationship of the lesion to the plane of the facial nerve (parotid masses), whether the lesion was intrinsic to the gland, and whether the lesion was aggressive. In the blinded reading, CT was superior to MR imaging in eight instances; in the final reading, however, with clinical information available, CT was superior in four cases of inflammatory salivary gland "masses." CT and MR imaging provided the same diagnostic information in all cases of salivary gland neoplasms. T1- and T2-weighted images proved of equal value in detection of salivary gland lesions, and use of both provided no additional specificity. In most cases, T1-weighted images alone provided the information necessary for surgical management. MR imaging is a reasonable first choice if a neoplasm is likely; the potential for improved tissue contrast at the margins of a tumor may be particularly useful. If a mass may be of inflammatory origin, contrast material-enhanced CT is a more reasonable first choice.     

Basal cell adenoma in the parotid gland: CT and MR findings

Basal cell adenoma is a rare benign salivary gland epithelial tumor, usually involving the parotid gland. We report CT and MR findings of three cases with basal cell adenoma occurring in the parotid gland. The three cases presented here demonstrate a well-circumscribed tumor, which showed a cystic and solid, or the pure solid mass. They were well enhanced after contrast matter injection. The solid portion of the mass was isoattenuated at CT, with intermediate signal intensity on T1- and T2-weighted MR images. Its cystic portion was hyperintense on both T1- and T2-weighted MR images. It had a hypointense rim on T2-weighted image.     

Delineation of gliomas with magnetic resonance imaging using Gd-DTPA in comparison with computed tomography and positron emission tomography

Fourteen patients with cerebral gliomas were investigated by MR imaging using Gd-DTPA (Magnevist), CT with the contrast agent iohexol (Omnipaque) and, as a reference, positron emission tomography (PET) using 11C-L-methionine. Tumour areas with disruption of the blood-brain-barrier (BBB) as seen on MR and CT were compared with areas increased accumulation of methionine in PET. There were 6 patients with high-grade astrocytoma (grade III-IV), 5 with low-grade astrocytoma (grade I-II) and 3 with oligodendroglioma. In 4 high-grade tumours, PET showed a larger tumour or tumour tissue in additional areas, compared with enhancement on MR and CT, while in 2 cases the tumour extension was similar in the three modalities. In the low grade tumour group, the findings on PET differed from those on post-contrast MR or CT in 7 cases. In 3 of these cases, no disruption of the BBB was seen either on MR or on CT. In 2 of our 14 patients CT showed larger enhancement extension than MR and in 2 cases MR was superior to CT in this respect. The enhancement intensity was higher on MR in 4 patients and on CT in 2 patients. No definite difference in the delineation of tumour tissue between the T1 weighted SE sequences was found. The gradient echo sequences FLASH and FISP gave limited information that was less than that provided by the T1 weighted SE sequences. A greater increase in signal intensity in T1 weighted images was usually seen 5 min post-contrast in the high-grade tumours than in the low-grade ones.     

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.     

MRI findings of mucoepidermoid carcinoma of the parotid gland: correlation with pathological features

Objective

The aim of this study was to correlate the MRI appearance and pathological findings in each grade of the mucoepidermoid carcinoma (MEC) of the parotid gland.

Methods

We reviewed surgically proven MECs of parotid glands in 20 patients. Pathologically, 5 tumours were high-grade, 3 were intermediate and 12 were low-grade. MR images were evaluated with emphasis on signal intensities on T₂ weighted images, margin characteristics and lymph node metastasis, correlating these with pathological features.

Results

Among the high-grade MECs, four out of five tumours showed inhomogeneous low to intermediate signal intensity on T₂ weighted images, reflecting high cellularity. All tumours had an ill-defined margin, reflecting invasive tumour growth. Among the intermediate-grade MECs, all three tumours showed intermediate signal intensity on T₂ weighted images and two tumours had an ill-defined margin. Among the low-grade MECs, 11 of the 12 tumours had a hyperintense area on T₂ weighted images because of the existence of abundant mucin secreting cells. Seven tumours had an ill-defined margin, reflecting peritumoural inflammatory changes rather than invasive tumour growth. Lymph node metastasis was seen in three high-grade MECs.

Conclusion

MECs of the parotid gland show variable MRI findings reflecting their histological nature, which seems to have certain tendencies depending on the tumour grade.Mucoepidermoid carcinoma (MEC) is the most common malignancy of the salivary gland, accounting for 3–15% of all salivary gland tumours. Their most favoured site is the parotid gland, which accounts for over 80% of MECs [1-4]. Histologically, MEC has been classified as low, intermediate or high grade according to intracystic components, mitotic figures, neural invasion, necrosis and cellular anaplasia. This histological grading has been reported as correlating with clinical behaviour [1-4]. Although clinical and pathological features of MEC have been well described, radiological features of MEC have not been systematically reported. In this study, we delineate MRI findings in each grade of MEC and correlate these with histological findings.     

Adult neuroblastoma: radiologic and clinicopathologic features

PURPOSE: The purpose of the current study was to define the imaging findings of adult neuroblastoma (ANB) and correlate them with clinicopathologic features. MATERIALS AND METHODS: The CT scans and MR images of six patients with histologically confirmed ANB (mean age, 49 years) were retrospectively analyzed. RESULTS: The arising sites of tumors included the retroperitoneum (n = 2), pelvis (n = 2), anterior mediastinum (n = 1), and adrenal gland (n = 1). The common CT finding was poorly marginated and heterogeneous mass without calcification. Cystic components were often found. On contrast-enhanced CT or MR images, tumors showed heterogeneous enhancement. On T2-weighted images, all masses demonstrated predominantly hyper signal intensity relative to skeletal muscle and the images showed heterogeneous appearance with focal areas of high intensity interspersed with septations of low signal intensity. Soft tissue masses with bone involvement were identified in one case on MR images. The CT findings in one tumor originating from mediastinum were similar to those of tumors arising from other sites. CONCLUSION: ANB is an uncommon malignancy that often pursues an aggressive clinical course, involves multiple sites, and has a poor prognosis. Tumors usually manifest on CT or MR images as a poorly demarcated mass mainly in the retroperitoneum and pelvis. Imaging studies can depict aggressive characteristics and disease extent of ANB.     

Nodular fasciitis in the head and neck: CT and MR imaging findings

BACKGROUND AND PURPOSE: The purpose of this study was to describe the CT and MR imaging findings of nodular fasciitis occurring in the head and neck region. METHODS: CT (n = 6) and MR (n = 4) images obtained from 7 patients (3 men and 4 women; mean age, 19.4 years; age range, 1-48 years) with surgically confirmed nodular fasciitis in the head and neck were retrospectively reviewed. All patients presented with a palpable mass in the head and neck that was noticed 1-3 months earlier: 5 in the face, one in the occipital scalp, and the remaining one in the supraclavicular fossa. We investigated the CT and MR imaging characteristics with emphasis on the location, size, internal content, margin, enhancement pattern, and signal intensity of the lesion. RESULTS: All lesions appeared as a discrete mass on imaging, ranging from 1.0 cm to 4.6 cm in diameter (mean, 2.2 cm). Six lesions, all of which appeared benign, were located in the subcutaneous tissue superficial to the deep cervical fascia. The remaining lesion was located deep to the temporalis muscle and showed an aggressive imaging appearance, markedly eroding the bony orbit and skull. Five lesions were solid, and 2 lesions were partly or completely cystic in appearance. Five lesions were well defined, whereas 2 lesions were ill defined. Four of 5 solid lesions showed moderate to marked diffuse enhancement, whereas the remaining lesion demonstrated mild enhancement. Two cystic lesions showed peripheral, nodular, or rim-like enhancement. Compared with muscle, both solid lesions had isointense signal intensity on T1-weighted images and hyperintense signal intensity on T2-weighted images, whereas the signal intensity of the solid portions of the deep-seated, partly cystic lesion was isointense on both T1-weighted and T2-weighted images. CONCLUSION: Although rare, nodular fasciitis occurs as a discrete solid or cystic mass in the head and neck, depending on the predominant stromal components. When one sees a head and neck mass with a superficial location and moderate to marked enhancement on CT and MR imaging, nodular fasciitis should be included in the differential diagnosis, especially in patients with a recently developed, rapidly growing mass and a history of recent trauma.     

眶壁转移瘤的CT和MRI诊断

目的分析研究眶壁转移瘤的CT和MRI特点,提高诊断准确率.方法回顾性分析23例经手术病理证实的眶壁转移瘤的CT和MRI表现,成人组16例,儿童组7例.所有病例均行CT平扫与MR平扫和增强扫描.结果16例成年患者CT表现均为溶骨性骨质破坏和眼眶不规则肿块,9例骨质破坏区邻近的颅内可见扁平不规则肿块;16例MRI表现为骨质破坏区邻近的眼眶和颅内均可见略长T1、略长T2信号的不规则软组织影,增强后呈明显强化.7例儿童患者CT表现均为溶骨性骨质破坏和眼眶不规则肿块,其中2例可见垂直针状高密度影,3例骨质破坏区邻近的颅内可见扁平不规则软组织肿块;MRI显示7例骨质破坏区邻近的眼眶内和6例颅内可见略长T1、略长T2信号不规则的软组织影,其中1例为双侧,增强后呈明显强化;7例双侧眶骨、4例斜坡和双侧岩尖及1例双侧颞骨鳞部骨髓腔呈略长T1、略长T2信号影,增强后呈明显强化.结论眶壁转移瘤的CT和MRI表现有一些特点,有助于诊断和鉴别诊断.     

Sialoblastoma (embryoma): MR findings of a rare pediatric salivary gland tumor.

We report the findings in a 21-month-old girl who had a noninfiltrating mass in the left cheek, just anterior to the masseter muscle, which, at surgery, proved to be a sialoblastoma. Sialoblastoma has a histologic appearance reminiscent of a primitive state of salivary gland development; that is, it shows an arrested state of salivary maturation. MR imaging in this case showed that the lesion was isointense with muscle on T1-weighted images, had a high-intermediate signal intensity similar to that of fat on T2-weighted images, and enhanced sparsely and nonhomogeneously.     

颈肩部纤维组织源性肿瘤的MR和CT诊断

目的 分析颈肩部促结缔组织增生性成纤维细胞瘤及侵袭性纤维瘤病的MR、CT特征，重点讨论MRI表现的病理基础。方法 分析手术病理证实有MR或CT影像资料的颈肩部促结缔组织增生性成纤维细胞瘤4例及侵袭性纤维瘤病3例的影像表现，并与病理对照。结果 （1）4例促结缔组织增生性成纤维细胞瘤均位于颈部肌间隙中，类圆形，边界大部分清晰，1例在MRI上见包膜样改变。CT平扫为均匀低密度（2例）及等低密度夹杂改变（1例），增强后肿块强化不明显，密度改变与平扫时一致。肿瘤在T1WI上为均匀等信号（1例）或等低信号混杂改变（1例）；T2WI上2例信号相似于邻近的肌肉，不均匀伴有结节样的低信号或略高信号；增强扫描，病灶强化不明显，仍以等肌肉信号为主，伴有灶性低或略高信号。（2）3例侵袭性纤维瘤病均起源于肌肉本身，长梭形生长，长径与所侵犯的肌肉走向一致，边缘均不规则。CT平扫为等肌肉密度、边界不清晰的肿块（2例）；MRT1WI为均匀等信号的占位，边界不清晰（3例）；T2WI见夹杂条状或结节状低信号的稍高信号（2例）或均匀高信号（1例）；增强扫描肿块均明显强化，条状或结节状的低信号影及不规则的边界显示更加清晰，2例见边缘爪样浸润改变。结论 好发于不同年龄的促结缔组织增生性成纤维细胞瘤和侵袭性纤维瘤病都为纤维来源的软组织肿瘤，但影像改变完全不同，这与其不同的病理基础密切相关。MRI的诊断及鉴别诊断作用明显优于CT。     

Epithelial-myoepithelial carcinoma of the parotid gland.

We describe an unusual salivary neoplasm, an epithelial-myoepithelial carcinoma (EMEC) of the parotid gland, that occurred in a 64-year-old man. A CT scan showed a fairly well defined heterogeneous lesion with smooth margins and slight enhancement. MR images showed a lesion with intermediate T1-weighted signal intensity and a relatively high T2-weighted signal intensity. Although the imaging characteristics of EMEC on both CT and MR studies are nonspecific, clinicians and radiologists must be aware of its high local recurrence rate, which has been reported to approach 50% in some series, and thus the need for periodic postoperative imaging to detect early recurrence.     

CT, MR, and Angiography Findings of a Solitary Fibrous Tumor of the Larynx: a Case Report

This report details the CT, MR, and angiography findings of a solitary fibrous tumor involving the larynx of a 34-year-old man. A precontrast CT scan revealed a well-defined isodense mass in the submucosal region of the supraglottic larynx. The tumor appeared as a mixed intensity lesion on the T1- and T2-weighted MR images. A T2-weighted MR image showed a central, round, and low signal intensity area within the mass. For both the CT and MR images, the mass demonstrated heterogeneous enhancement following the administration of contrast material. The angiography showed a hypervascular tumor with heterogeneous persistent staining.     

Acinic cell carcinoma of the head and neck: radiologic-pathologic correlation

OBJECTIVE: To describe and correlate the imaging and pathologic findings of acinic cell carcinoma (ACC) in the head and neck. METHODS: We reviewed the radiologic findings of 12 patients with pathologically proven ACC in the head and neck. They were 6 males and 6 females (ages: 5-75 years, mean 36 years) who undergoing computed tomography (CT, n=9) and CT with magnetic resonance (MR) imaging (n=3). RESULTS: The lesions in the superficial lobe of the parotid gland were solid (n=7), cystic (n=1), and cystic mass with mural nodule (n=1) on CT. A parapharyngeal lesion was cystic mass with mural nodule, and a submandibular and a palate tumor were cystic lesions on CT. All solid masses in the parotid gland (n=7) included focal low-attenuating portions on CT, which were microcyst, hemorrhage, or necrosis on pathologic examination. We could not find intratumoral calcifications or metastatic lymphadenopathy on imaging and histologic studies in all 12 cases. Internal hemorrhage on the MR images was seen in a parapharyngeal and a parotid lesion. CONCLUSION: Although ACC appears to have nonspecific imaging findings, familiarity with some imaging features can be helpful for differential diagnosis of head and neck tumors.     

Magnetic resonance imaging of the solitary hepatic mass: Direct correlation with pathology and computed tomography

Magnetic resonance images (MRI) of the liver were obtained using a combination of short time inversion recovery (STIR) and spin echo (SE) sequences. These were correlated with comparable tissue slices generated from resected specimens obtained at partial hepatectomy. All 10 cases appeared to have solitary masses on contrast enhanced computed tomography (CT). Histological examination revealed five primary tumours (two hepatocellular carcinomas, two haemangiomas and one cholangiocarcinoma) and five metastatic tumours. The STIR images demonstrated a high signal intensity in all areas of viable tumour involvement and reduced signal intensity in regions of confluent necrosis with superimposed haemorrhage or calcification. This sequence also demonstrated additional areas of high signal intensity adjacent to several lesions which were not visible on CT. Microscopy of these regions in the specimens demonstrated no tumour involvement or steatosis and their precise cause remains obscure. All the lesions demonstrated on the CT images were visible on MRI and no additional lesions were discovered on detailed microscopical examination of the specimens. Delineation of the extent of the cholangiocarcinoma was a problem with both techniques. MRI showed no major advantage over CT except for a higher contrast of the lesion compared with normal liver and also a better delineation of the tumour mass.     

PET/CT and MRI of intra-osseous haemangioma of the tibia

Intra-osseous haemangioma is a rare, benign neoplasm that usually involves the vertebrae and craniofacial bones. Furthermore, its occurrence in the long bones is extremely rare. We report the findings of fluorine-18-fludeoxyglucose ((18)F-FDG) positron emission tomography (PET)/CT and MRI in a patient with intra-osseous haemangioma in the proximal tibia, who was initially misdiagnosed as having a malignancy based on (18)F-FDG PET/CT. (18)F-FDG PET/CT showed a well-marginated osteolytic lesion with abnormal FDG uptake. The mass demonstrated low signal intensity on T(1) weighted MRI. On T(2) weighted images, the lesion appeared as a cluster of high signal intensity lobules and showed strong enhancement on contrast-enhanced T(1) weighted images. Surgical curettage was performed and histopathological examination of the excised tissue confirmed a cavernous haemangioma.     

Giant cell tumor of the thoracic spine simulating mediastinal neoplasm.

A case of giant cell tumor of the thoracic spine simulating mediastinal neoplasm was identified on plain films, CT scans, MR images, and with scintigraphy. CT showed a hypervascular soft-tissue mass with shell-like calcification in the right upper mediastinum. MR imaging showed a collapse of the T1 vertebral body and a mass extending to the mediastinum. The mass had a low signal on T1-weighted MR images and a predominantly high signal on T2-weighted images with heterogeneity. Technetium-99m methylene diphosphonate bone scintigraphy showed intense uptake in both the T1 and marginal parts of the mediastinal mass. There was no accumulation of gallium-67 citrate, but 18-fluorine fluorodeoxyglucose positron emission tomography showed marked uptake. The variation in these imaging findings played an important role in the differential diagnosis of this uncommon mediastinal mass.