A case of cystadenocarcinoma of the ectopic salivary gland: comparison of pre-operative ultrasound, CT and MR images with the pathological specimen

Cystadenocarcinoma is a rare salivary gland tumour. Only a few case studies have provided pre-operative images of these tumours. This report demonstrates the case of a 28-year-old male with cystadenocarcinoma arising from an ectopic salivary gland with lymph node metastasis in the right upper neck. Ultrasound including Doppler images showed two masses with scant vascular flow. One was a hyperechoic mass enclosed within a low echoic cystic lesion and the other was a solid hypoechoic mass. Contrast enhancement CT scans demonstrated a ring enhanced mass and weakly homogeneous enhanced masses in the right upper neck. Dynamic studies showed increased enhancement in delayed phase CT that was the same as that in other malignant salivary gland tumours. Moderate to slightly high signal intensity was seen on T(1) weighted MR images and axial T(2) weighted MR images showed one heterogeneous mass in a high signal lesion and a moderate to high signal intensity mass. The authors discuss the pre-operative findings of ultrasound with Doppler imaging of this neoplasm, and CT findings including dynamic study images and MRI, comparing the findings with the post-operative pathological features of the tumour.     

Diagnostic value of gadopentetate dimeglumine for 1.5-T MR imaging of musculoskeletal masses: comparison with unenhanced T1- and T2-weighted imaging.

Three magnetic resonance (MR) imaging techniques (T1-weighted, T2-weighted, and T1-weighted gadopentetate dimeglumine--enhanced) were compared in 32 consecutive MR imaging studies of 26 patients with suspected musculoskeletal masses. T2-weighted images were superior to T1-weighted enhanced images with respect to detection and definition of lesions in 12% of cases (n = 4) and were equal in 88% of cases (n = 28). T2-weighted images were also superior to T1-weighted images in 38% of cases (n = 12). In no cases were T1-weighted enhanced images superior to T2-weighted images. In two cases, T1-weighted images were superior to both T1-weighted enhanced and T2-weighted images. The authors conclude that gadopentetate dimeglumine did not provide much value in lesion detection above that obtained with T2-weighted images. They also conclude that T1-weighted images were occasionally superior to T1-weighted enhanced images and T2-weighted images because of loss of definition between fat and lesion on the latter.     

Adnexal masses: MR imaging observations at 1.5 T, with US and CT correlation

To assess the role of 1.5-T magnetic resonance (MR) imaging in evaluation of the adnexa, 43 consecutive examinations that revealed 61 adnexal masses were retrospectively reviewed. T1- and T2-weighted images in coronal, axial, and/or sagittal planes were included. Available ultrasound (US) (n = 30) and/or computed tomographic (CT) (n = 9) scans were then correlated with the MR images. On T2-weighted images at least part of all adnexal masses was of higher signal intensity than surrounding muscle and adipose tissue, and therefore the adnexal masses were best seen with these sequences. T1-weighted imaging improved tissue characterization by revealing signal characteristics of fat in teratomas and characteristics of blood in endometriomas or hemorrhagic cysts, pelvic inflammatory disease, ovarian carcinomas, serous cystadenomas, and teratomas. MR imaging provided additional information or increased diagnostic confidence in 25 of 30 patients who underwent US or CT. MR imaging is a promising problem-solving modality after US in the study of adnexal abnormalities.     

Magnetic resonance imaging of adrenal cortical carcinoma

Five cases of adrenal cortical carcinoma examined with magnetic resonance (MR) are presented. Clinical histories, computed tomographic (CT) scans, and final pathologic findings were reviewed in each case. All masses were hypointense compared to the liver on T1-weighted images and became hyperintense compared to the liver on T2-weighted images. Signal intensity of adrenal masses, fat, and liver were measured. Adrenal/liver and adrenal/fat signal intensity ratios were then calculated. All the masses were readily identified with MR. The MR also demonstrated displacement or invasion of adjacent organs, as well as liver metastases. The inferior vena cava was also identified in each case. Even though there were no consistent MR findings to diagnose adrenal cortical carcinomas accurately, superior blood vessel identification and multiplanar capabilities may make MR the imaging modality of choice in evaluating the extent of disease and in planning surgical excision.     

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.     

Mediastinal lesions in children: comparison of CT and MR

Magnetic resonance (MR) imaging was compared with computed tomography (CT) in 13 children with mediastinal abnormalities. CT and MR provided comparable information regarding the presence and size of the mediastinal lesions. The MR imaging technique that was most reliable in detecting a mass was a T1-weighted spin-echo pulse sequence. MR better discriminated mediastinal masses and enlarged nodes from vascular structures and was more sensitive than CT in detecting intraspinal extension. However, CT demonstrated calcification and bronchial abnormalities not seen on MR images. It is concluded that MR may be more helpful than CT in evaluating posterior mediastinal tumors, since there is a likelihood of intraspinal extension. In other cases, however, CT continues to be the procedure of choice to supplement plain radiography in children with suspected mediastinal neoplasms.     

Middle ear cholesteatoma extending into the petrous apex: evaluation by CT and MR imaging

CT and MR imaging findings were reviewed in four cases of acquired cholesteatoma of the middle ear that extended medially into the petrous apex and middle cranial fossa. In one case the lesion further extended anteromedially into the sphenoid sinus. CT demonstrated the lesions as nonenhancing hypodense masses with bone destruction, extending medially from the middle ear cavity to the petrous apex region. On MR imaging, the lesion was slightly hypointense relative to brain on T1-weighted images and hyperintense on T2-weighted images. MR imaging clearly delineated the extraaxial location of the lesion and associated brain displacement. The medial extension of the cholesteatomas seems to have proceeded via a detour around the bony labyrinth into the petrous apex region by following normal pathways of temporal bone pneumatization.     

MR imaging of myositis ossificans: Variable patterns at different stages

Five patients with a palpable mass at presentation underwent magnetic resonance (MR) imaging. The final diagnosis was myositis ossificans (MO). MR imaging features, particularly after injection of gadopentetate dimeglumine, mimicked those of an inflammatory mass or neoplasm. The lesions were excised in three patients, and the Images were correlated with histologic findings. Three different appearances were noted on MR images, corresponding to the stages of maturation of MO. Two cases Involved early-stage lesions, and Tl-weighted MR images showed a mass with homogeneous intermediate signal intensity. Both lesions showed rim enhancement after contrast agent injection and high signal intensity on T2-weighted images. Pathologic specimens demonstrated stroma with masses of spindle cells in which osteoid production was interspersed. The enhanced rim of the lesion mimicked the expected MR appearance of an abscess or necrotic tumor. Areas of enhancement in adjacent muscle were also seen on postcontrast T1-weighted images. Intermediate-stage MO was present in one case; there was evidence of a thin rim of calcification on plain radiographs and fatty changes in the lesion on T1-weighted Images, corresponding with histologic findings. One case of a mature lesion showed a considerable degree of peripheral calcification both on MR images and at histology. MR imaging is nonspecific in the diagnosis of early-stage MO.     

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.     

CT and MR imaging of craniopharyngioma

We reviewed imaging findings of CT and MR imaging in 20 cases of surgically confirmed craniopharyngioma in an attempt to determine their relation to patterns of tumor extent. The relationship between these patterns and the frequency of preoperative CT diagnosis and MR imaging diagnosis according to the surgical diagnosis were determined. The CT technique was superior to MR imaging in the detection of calcification. The MR imaging technique was superior to CT for determining tumor extent and provided valuable information about the relationships of the tumor to surrounding structures. Thus, CT and MR imaging have complementary roles in the diagnosis of craniopharyngiomas. In cases of possible craniopharyngioma, noncontrast sagittal T1-weighted images may enable the identification of the normal pituitary, possibly leading to the correct diagnosis. Received 6 November 1995; Revision received 9 August 1996; Accepted 14 October 1996     

Fibrosing inflammatory pseudotumors involving the skull base: MR and CT manifestations with histopathologic comparison.

PURPOSETo describe the MR and CT features of fibrosing inflammatory pseudotumors of the skull base region, and to document the MR signal intensity of the lesions with histopathologic comparison.METHODSWe reviewed the MR and CT studies of five patients with pathologically proved fibrosing inflammatory pseudotumor involving the skull base. Unenhanced spin-echo T1- and T2-weighted and contrast-enhanced T1-weighted MR images were obtained at 0.5 T in three patients and at 1.5 T in two patients. MR findings were correlated with histopathologic findings in all five cases, and the enhancement pattern was compared with CT findings in three cases.RESULTSIn three cases, the cavernous sinus was involved unilaterally, with adjacent extracranial infiltrative masses. In one case, both orbits, the cavernous sinuses, and the tentorium were involved with diffuse infiltrative lesions. One patient had an infiltrative nasopharyngeal mass; and in all five patients, MR images showed localized involvement of the skull base, with bone marrow replaced by tumor. The soft-tissue lesions were hypointense on T2-weighted images in all five cases and showed homogeneous contrast enhancement. Histopathologic studies revealed scanty inflammatory cell infiltration with densely fibrotic background in all cases. The hypointensity of the lesions on T2-weighted images seemed to be related to the degree of fibrosis.CONCLUSIONFibrosing inflammatory pseudotumor shows characteristic MR findings of infiltrative lesion with bone destruction and hypointensity on T2-weighted images. The lack of mobile protons due to the fibrotic background and/or high cellularity of the lesions may be the reason for their hypointensity and weaker enhancement on MR images.     

Sinonasal tumors and inflammatory tissues: differentiation with MR imaging

The magnetic resonance (MR) and computed tomographic (CT) images of 53 patients with sinonasal tumors were analyzed and compared for accuracy in tumor mapping. the findings were confirmed by means of either surgery or biopsy. The MR images of 60 patients with inflammatory disease were also studied, and the findings were confirmed at surgery. Forty-seven additional MR images were also examined of patients with tumors showing histologic characteristics similar to those found in the sinonasal tumor group but occurring elsewhere in the head and neck, excluding the orbit. This study concludes that nearly 95% of sinonasal tumors have an intermediate T2 signal, while only 5% have bright T2 signals. This small latter group is composed almost exclusively of some minor salivary gland tumors and some neuromas. The inflammatory tissues all had bright T2 signals. The distinction between sinonasal tumors and inflammatory tissues was best accomplished with T2-weighted studies, and MR imaging was more accurate than CT.     

Bicipital radial bursitis: CT and MR appearance

The authors present two cases of bicipital radial bursitis in the elbow. In these two cases, different CT and MR imaging patterns were observed. In the first case, postcontrast CT inhomogeneously enhanced the entire lesion. T1-weighted MR images showed the lesion with iso-signal intensity with muscle. T2-weighted images demonstrated the lesion with inhomogeneous high signal intensity, with internal, linear hypointensity. Histologically, the lesion consisted of hypertrophic synovia. In the second case, postcontrast CT failed to enhance the lesion. T2-weighted MR images showed the lesion with homogeneous, marked high signal intensity. Histologically, the lesion consisted of a monocystic bursa lined by thin synovial lining layers.     

MR imaging of thyroid hemochromatosis

We present the magnetic resonance (MR) images of exogenous hemochromatosis in the thyroid gland. On both T1-weighted images and T2-weighted images the thyroid showed low intensity similar to that of the background. Magnetic resonance is of value in imaging the tissue deposition of iron. In assessing thyroid iron accumulation, MR is superior to CT because CT can not differentiate iron deposition from normal iodine concentration.     

Primary thyroid lymphoma: MR appearance

Magnetic resonance imaging was evaluated in six patients with primary thyroid lymphoma. Five patients had a solitary localized tumor and one had multiple tumors. These masses showed homogeneous iso- or high intensity compared with the uninvolved thyroid tissue on T1-weighted images and homogeneous high intensity on T2-weighted images. Diffuse lobulated goiter with homogeneous intensity was seen in the sixth case, where the differentiation between lymphoma and Hashimoto thyroiditis was impossible. Extrathyroidal tumor extension occurred in two cases and cervical lymphadenopathy in one case. In five of six cases, identification and staging of primary thyroid lymphoma were possible with MR imaging. Magnetic resonance imaging was comparable to CT in the detection of tumors (five cases), extrathyroidal extension (two cases), and cervical lymphadenopathy (one case). In three cases, the pseudocapsule (a low-intensity band forming the border between tumor and thyroid tissue) was detected only by MR imaging. In one case, the discrimination between tumor and uninvolved thyroid gland was clearer on MR imaging than on CT.     

软骨肉瘤的影像诊断与鉴别诊断

目的:探讨软骨肉瘤的影像学表现,提高对本病诊断的准确性。方法:回顾性分析25例经手术病理证实的软骨肉瘤的X线、CT和MRI资料。结果:25例软骨肉瘤中原发23例,其中普通型20例,去分化型、黏液型及透明细胞型各1例;继发2例。X线及CT表现:原发的23例中溶骨性骨破坏5例,混合性骨破坏18例,形成软组织肿块20例,其中表现为低密度19例,等密度1例。20例普通型及1例黏液型见散在钙化。MRI表现:普通型软骨肉瘤T1WI呈等或稍低信号,T2WI呈等或稍高信号;黏液型T1WI呈等、低混杂信号,T2WI呈稍高、低的混杂信号,钙化T2WI呈低信号;透明细胞型病例T1WI及T2WI呈近乎等信号;去分化型T1WI呈等低混杂信号,T2WI呈不均匀高信号。6例普通型及1例继发型出现环形、间隔样中等-明显强化,黏液型及去分化型呈不均匀中等-明显强化。结论:普通X线及CT是软骨肉瘤影像诊断及鉴别诊断的主要手段,MRI显示软骨信号为重要提示。MRI显示病变范围更为清楚、准确,为临床治疗提供可靠依据。     

The MR appearance of hypothalamic hamartoma

Summary Hypothalamic hamartoma is the most common detectable cerebral lesion causing precocious puberty. Two histologically confirmed cases were studied by computerized tomography (CT) and magnetic resonance (MR) imaging. T2 weighted, sagittal MR images were superior to CT in delineating the tumor from surrounding grey matter. The lesion was isointense to grey matter on T1 weighted images allowing exclusion of other hypothalamic tumors. MR will undoubtedly become the imaging modality of choice in the detection of hypothalamic hamartoma.     

1.5-T MR imaging of pituitary microadenomas: technical considerations and CT correlation

Thirty-seven patients with suspected pituitary tumors were evaluated prospectively with MR imaging at 1.5 T. MR detected a microadenoma at its correct location in all eight patients who underwent transsphenoidal surgery, while CT showed a focal abnormality in the correct location in only four of the eight patients. In patients who were clinically and endocrinologically considered to harbor a microadenoma, MR detected a focal pituitary signal abnormality in 83% and CT demonstrated a focal density abnormality in 42%. Infundibular displacement, focal gland convexity, and sellar-floor abnormality were seen equally well with CT and MR. MR imaging protocol included sagittal T1-weighted spin-echo, coronal inversion-recovery, and coronal spin-echo or cardiac-gated spin-echo images. Although inversion-recovery images were superior in detecting focal pituitary lesions, some microadenomas were better seen on T2-weighted images. Cardiac-gated spin-echo images showed focal pituitary lesions better than ungated images did. Our technique demonstrates MR's superior sensitivity to CT in detecting a pituitary microadenoma.     

Irradiated carcinoma of the tongue: correlation of MR imaging findings with pathology

OBJECTIVE: MR imaging was prospectively correlated with pathologic findings to study whether MR imaging can differentiate viable from nonviable tumor tissue in the irradiated carcinoma of the tongue. SUBJECTS AND METHODS: MR examinations were performed after radiation therapy in 21 patients with carcinoma of the tongue. All patients underwent either a total glossectomy or hemiglossectomy after radiation therapy. Specimens were examined microscopically. Radiation changes were histologically graded into four groups (I, minimal cellular changes; II, presence of cellular changes and partial destruction of the tumor; III, only nonviable tumor cells; IV, no tumor cells). MR examinations included T2-weighted imaging, unenhanced T1-weighted imaging, dynamic contrast-enhanced imaging, and contrast-enhanced T1-weighted imaging. RESULTS: On unenhanced T1-weighted images, the lesion was hypointense, except for two patients with histologic grade III. On T2-weighted images, the lesion appeared hyperintense in 12 of 14 patients with viable tumor cells (grades I and II); however, the lesion was hypointense in four, and isointense in two of seven patients with nonviable tumor cells (grades III or IV). Contrast-enhanced T1-weighted images showed that the degree of contrast enhancement of the lesion was equal to or lower than that of a normal salivary gland in 18 of 21 patients. For the time of maximal enhancement of the lesion on dynamic imaging, there was no substantial difference between viable (grades I and II) and nonviable (grades III and IV) tumor tissue. CONCLUSION: The present study shows that T2-weighted imaging is feasible for differentiating viable from nonviable tumor tissue in irradiated carcinoma of the tongue.     

Improved detection and delineation of head and neck lesions with fat suppression spin-echo MR imaging.

To compare conventional and fat suppression MR imaging in their ability to detect head and neck lesions, we prospectively studied 17 patients with head and neck tumors and one normal volunteer. Five patients had benign tumors (one mixed cell tumor, one hemangioma, one lipoma, and two plexiform neurofibromas), 10 had malignant tumors (six squamous cell carcinomas, two minor salivary gland carcinomas, one lymphoma, and one malignant fibrous histiocytoma), and two had nonspecific lymphadenopathy. All subjects were studied with standard spin-echo T1- and T2-weighted images (T2-weighted imaging was done with and without fat suppression technique). In addition, T1-weighted images with contrast enhancement and fat suppression were obtained in nine patients. A four-point grading system was used for comparison of the conventional and fat suppression images. Grades ranged from 0 (unsatisfactory, the lesion cannot be seen) to 3 (excellent, the lesion and its margins can be seen clearly with sharp contrast from surrounding normal tissue). We found that postcontrast fat suppression T1-weighted images and fat suppression T2-weighted images were most useful; these sequences obtained an average score close to grade 3 (2.77 and 2.85, respectively). On the other hand, the conventional T2-weighted images had an average score of about 2 (1.82) and the conventional T1-weighted image had a score of about 1 (1.33). Fat suppression T2-weighted sequences generally were superior in cases of lymphadenopathies. Postcontrast T1-weighted images were most useful in a case of plexiform neurofibroma, owing to their fibrous component and lower proton density.(ABSTRACT TRUNCATED AT 250 WORDS)