Foreign Body Granulomas Simulating Recurrent Tumors in Patients Following Colorectal Surgery for Carcinoma: a Report of Two Cases

We report here two cases of foreign body granulomas that arose from the pelvic wall and liver, respectively, and simulated recurrent colorectal carcinomas in patients with a history of surgery. On contrast-enhanced CT and MR images, a pelvic wall mass appeared as a well-enhancing mass that had invaded the distal ureter, resulting in the development of hydronephrosis. In addition, a liver mass had a hypointense rim that corresponded to the fibrous wall on a T2-weighted MR image, and showed persistent peripheral enhancement that corresponded to the granulation tissues and fibrous wall on dynamic MR images. These lesions also displayed very intense homogeneous FDG uptake on PET/CT.     

Basal cell adenoma in the parapharyngeal space: MR findings

We report MR findings of a case of basal cell adenoma arising in the parapharyngeal space. On MR imaging, the mass was a well-circumscribed cystic and solid tumor with a thin fibrous capsule and intratumoral hemorrhage. It was confined to the parapharyngeal space, separating from the deep lobe of the parotid gland. The solid portion of the tumor was slightly hypointense/hyperintense to the muscle on T1-/T2-weighted images and was relatively well enhanced on Gd-enhanced T1-weighted images. The cystic contents of the mass were hyperintense on both T1- and T2-weighted images and were proven to be a hemorrhage.     

Atypical MRI features of a biliary cystadenoma revealed by jaundice

We report on the case of a patient admitted for epigastric pain. An abdominal ultrasound revealed a voluminous cystic lesion of the left hepatic lobe. In magnetic resonance imaging, the mass had a liquid–liquid level that was spontaneously hyperintense on T₁-weighted images and hypointense on T₂-weighted images.

Magnetic resonance cholangiography identified bilateral intrahepatic bile duct dilatation. A left hepatectomy finally revealed a mucinous cystadenoma with pseudo-ovarian stroma that had a pedunculated intraductal extension to the biliary convergence.     

Splenic hamartoma: a case report

Splenic hamartomas are rare benign tumours composed of an abnormal mixture of normal components of the spleen. Generally asymptomatic, they are in most insances discovered as incidental findings at laparotomy or autopsy. We report a case in which sonography disclosed a heterogenous splenic mass, partially cystic, with some echogenic foci thought to represent calcification. CT was unremarkable, d detecting a spontaneously isodense mass with a small peripheral calcification. Scintigraphy performed with sulphur colloids demonstrated an area of increase uptake. MRI disclosed a slightly hypointense mass on T1-weighted spin-echo images which was predominantly hypointense with a more isointense central area on long TR/TE images. On gadolinium-enhanced T1-weighted images the mass displayed a heterogenous hyperintensity with prolonged enhancement. Biopsy was inconclusive and the final diagnosis was achieved only with splenectomy. Correspondence to: P. O. Pinto     

MR evaluation of adrenal masses at 1.5 T

We retrospectively studied the value of MR imaging at 1.5 T to distinguish between nonadenomatous (n = 17) and adenomatous (n = 15) adrenal masses on the basis of (1) signal-intensity ratios on T1- and T2-weighted spin-echo images, (2) T2 relaxation times, and (3) T2 relaxation-time ratios. Univariate and then multivariate logistic regression were applied to these quantitative parameters to determine which of these best discriminated nonadenomas from adenomas, and whether or not more than one of these parameters improved the prediction. The adrenal mass/liver signal-intensity ratio on T2-weighted spin-echo images could not be used to differentiate nonadenomas from adenomas. Adrenal mass/fat signal-intensity ratios on T2-weighted spin-echo images, adrenal/liver T2 relaxation-time ratios, and adrenal mass T2 relaxation times were best for distinguishing nonadenomas from adenomas. By using a T2 value of greater than 61 msec, the true-positive ratio/false-positive ratio of differentiating nonadenomas from adenomas was 100%/20%; at greater than 82 msec, it was 64%/0.06%. The adrenal mass/fat signal-intensity ratios on T2-weighted spin-echo images and the adrenal/liver T2 relaxation-time ratios showed similar inherent discriminatory capacity. Overlap remains despite the use of these parameters. On the basis of this preliminary information, we conclude that MR has merit for the characterization of adrenal masses at 1.5 T. T2 relaxation time of the adrenal mass shows the greatest promise for discriminating nonadenomas from adenomas.     

Myxoid solitary fibrous tumor of the retroperitoneum: MRI findings with the pathologic correlation.

We report here on a case of solitary fibrous tumor of the retroperitoneum, and the tumor displayed a predominantly myxoid histology. A 56-year-old man presented with an incidentally detected retroperitoneal mass. On the MR images, the mass was observed as having iso-signal intensity on the T1-weighted images and high signal intensity on the fat-saturated T2-weighted images. The mass showed intense enhancement on the Gd-DTPA enhanced T1-weighted images. At surgery, a well-defined solid mass was found in the left retroperitoneum. The histological diagnosis was made as solitary fibrous tumor with a predominantly myxoid histology.     

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.     

Case report: Ovarian cavernous haemangioma presenting as a heavily calcified adnexal mass

Haemangioma is an extremely rare tumour of the ovary. We describe the CT and MRI findings of a heavily calcified ovarian haemangioma in a 69-year-old woman presenting with adnexal torsion. CT showed a well-circumscribed mass with extensive punctate calcifications, located posterior to the uterus. MR images showed dark signal intensities of the mass on both T(1) and T(2) weighted images, with poor enhancement of the mass on contrast-enhanced T(1) weighted images. MR images also demonstrated a beak-like protrusion from the adnexal mass, representing the adnexal torsion. This is the first case report of a heavily calcified ovarian haemangioma in the English literature. Although rare, ovarian haemangioma should be included in the differential diagnosis of a heavily calcified adnexal mass.     

Imaging features of myoepithelioma arising from the hard palate. A case report

A 53-year-old Japanese woman presented with a mass of the hard palate that was histologically diagnosed as myoepithelioma. By CT, the well-demarcated ovoid isodense mass showed faint contrast enhancement. By MR imaging, the mass was homogeneous and isointense on T1-weighted images with homogeneous enhancement after administration of contrast material and markedly hyperintense on T2-weighted images. Myoepithelioma should be kept in mind as differential diagnosis of hard palatine tumors.     

Extraosseus uptake of F-18 fluoride in the primary malignancy and cerebral metastasis in a case of non-small-cell lung cancer

A 68-year-old man with history of heavy smoking was admitted for increasing falls during the past 4 weeks. Chest x-ray revealed a right upper lobe mass. Biopsy demonstrated poorly differentiated non-small-cell carcinoma. F-18 fluoride positron emission tomography/computer tomography (PET/CT) was performed to evaluate bone metastasis. Review of the sectional PET images demonstrated extraosseous fluoride uptake in the primary lung mass, as well as ring-shaped fluoride uptake in the cerebral metastatic lesion. Neither of these lesions demonstrated calcifications on CT images. The patient received radiation treatment of the brain metastasis after F-18 fluoride PET/CT study.     

Variability of repeated coronary artery calcium measurements by 1.25-mm- and 2.5-mm-thickness images on prospective electrocardiograph-triggered 64-slice CT

High reproducibility on coronary artery calcium scoring is a key requirement in monitoring the progression of coronary atherosclerosis. The purpose of this prospective study is to assess the reproducibility of 1.25-mm- and 2.5-mm-thickness images on prospective electrocardiograph-triggered 64-slice CT with respect to 2.5-mm-thickness images on spiral overlapping reconstruction. One hundred patients suspected of coronary artery disease were scanned twice repeatedly, both on prospective electrocardiograph-triggered step-and-shoot and retrospective electrocardiograph-gated spiral scans. Using 1.25-mm-thickness collimation, 1.25-mm- and 2.5-mm-thickness image sets on prospective scans and 2.5-mm-thickness image sets with 1.25-mm increment (overlapping) on retrospective scans were obtained. Coronary artery calcium scores, interscan variability and interobserver variability were evaluated. The mean interscan variability in coronary artery calcium measurement on 1.25-mm prospective/2.5-mm prospective/2.5-mm overlapping retrospective scans were Agatston: 10%/18%/12%, volume: 10%/12%/10% and mass: 8%/13%/11% for observer 1 and Agatston: 8%/14%/10%, volume: 7%/9%/10% and mass: 7%/10%/9% for observer 2, respectively. The mean interobserver variability was 5% to 14%. In conclusion, prospective electrocardiograph-triggered 64-slice CT using the 1.25-mm prospective scan shows the lowest variability. The 2.5-mm prospective scan on volume or mass scoring shows variability of around 10%, comparable to 2.5-mm-thickness spiral overlapping reconstruction images.     

Imaging features of intraventricular melanoma.

We present the MR imaging findings in a patient with symptoms of increased intracranial pressure and a mass in the left lateral ventricle. The mass showed increased signal intensity on T1-weighted images and low signal intensity on T2-weighted images. The histologic diagnosis was that of melanoma, and detailed physical and funduscopic examinations disclosed no evidence of a primary lesion. We believe that the mass was a primary intraventricular melanoma, possibly arising from the choroid plexus, and we discuss the mechanisms that may be responsible for its occurrence in this location.     

脾脏炎性假瘤的影像学表现（附三例报告）

目的 报道3例脾脏炎性假瘤的影像学表现,以提高对本病的认识。方法 复习3例脾脏炎性假瘤的超声、CT扫描和1例MRI表现,并与病理表现进行对照。结果 B超表现为单发球形病变,回声不均匀、边界清楚,其中1例见环状强回声伴后方声影。3例CT平扫见脾内边界清楚的低密度肿块,1例见周边蛋壳样环状钙化;2例作增强扫描,1例静脉期略有增强,另1例延迟扫描病变强化程度与脾实质接近;1例又作MR平扫,T1、T2WI均以低信号为主。结论 脾脏炎性假瘤应列入脾单发肿物的鉴别诊断,其影像表现与肿块内纤维组织和炎性肉芽组织的多少有关。超声表现为边界清楚、回声不均的肿块;CT增强扫描以病变延迟强化为特点;MRT2WI常以低信号为主。     

MR findings of subarachnoid dissemination of a pituitary adenoma

Although pituitary adenoma is a benign tumour, subarachnoid dissemination occurs rarely. We describe a case of pituitary adenoma with subarachnoid dissemination. After the third operation for pituitary adenoma, an extraaxial mass was demonstrated on MR images. On T1 and T2 weighted images, the signal intensities of the extraaxial mass were similar to those of the primary pituitary adenoma. On dynamic contrast T1 weighted images, the time-intensity curve of the extraaxial mass, which showed early and persistent signal intensity, was also similar to that of the primary pituitary adenoma. These MR findings are considered to reflect the similar vascularity and stroma of the extraaxial mass and the primary pituitary adenoma.     

Spinal intradural capillary hemangioma: MR findings

We report a case of a spinal intradural capillary hemangioma. On MR images, a well-circumscribed intradural mass was detected at the T8-T9 level. The signal intensity of the mass relative to the spinal cord was isointense on T1-weighted images, hyperintense on T2-weighted images, and showed homogeneous, strong enhancement on contrast-enhanced T1-weighted images. The mass had both extramedullary and intramedullary components.     

Solitary fibrous tumor of the pancreas

A solitary fibrous tumor (SFT) originating in the pancreas is rare. We report a 55-year-old woman with an asymptomatic pancreatic mass incidentally discovered on abdominal ultrasonography. Contrast-enhanced computed tomography (CT) showed a well-demarcated exophytic mass in the pancreatic head with prolonged and delayed enhancement. The mass showed hypointensity on T1-weighted images and heterogeneous hypointensity with spotty hyperintensity foci on T2-weighted images. Fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT showed no significant FDG uptake. The resected mass was composed of spindle cells that were positive for CD34; and hemangiopericytomatous vessels were focally detected. The mass was finally diagnosed as an SFT of the pancreas.     

Ovarian fibroma (fibrothecoma) with extensive cystic degeneration: unusual MR imaging findings in two cases

Two cases of ovarian fibroma (fibrothecoma) with extensive cystic degeneration are described. One case revealed a large multiloculated cystic mass with a small solid part. Each locule showed variable signal intensity on both T1- and T2-weighted magnetic resonance (MR) images. The other case revealed a parviloculated cystic mass with a small solid part. In both cases, the solid parts were located at the periphery of the mass and showed distinct low signal intensity on both T1- and T2-weighted MR images and slight enhancement. It should be noted that ovarian fibromas (fibrothecomas) with extensive cystic degeneration are a rare exception to the rule that solid components in a cystic adnexal mass imply malignancy.     

Perirectal cystic paragonimiasis: endorectal coil MRI

We report the transrectal ultrasonographic (TRUS) and endorectal surface coil MR findings for paragonimiasis involving the perirectal space. The patient presented with voiding difficulty. TRUS showed a well demarcated, oval-shaped hyperechoic mass in the perirectal space. On endorectal MR images, the lesion was depicted as a well defined cystic mass with homogeneous intermediate signal intensity on T1-weighted images and heterogeneous hyperintensity on T2-weighted images. Ectopic paragonimiasis can appear as a well defined cystic mass in the peritoneum and should be included in the differential diagnosis of cystic mass in the abdomen and pelvic cavity, including the perirectal space.     

18F-FDG PET/CT and PET/MRI fusion imaging for neuroendocrine carcinoma of the tongue: A case report

Neuroendocrine carcinoma (NEC) involving the tongue is a rare and aggressive disease that is more common in middle-aged and elderly males. We report a case of a 56-year-old male who presented to our hospital with sore throat and was found to have a mass in the left root of the tongue. ¹⁸F-FDG PET/CT revealed intense FDG uptake in the mass of the tongue base, as well as different uptake of FDG in the mid-posterior mediastinal mass, right adrenal gland, and enlarged lymph nodes in the neck and mediastinum. Gadolinium-enhanced MRI clearly showed the extent of the tongue lesion, additionally suggesting the presence of brain metastases. ¹⁸F-FDG PET/MRI fusion images of the neck were obtained on the workstation, which may have a higher diagnostic value for tongue NEC. The patient underwent a biopsy of the mass in the left root of the tongue and was pathologically diagnosed with NEC. Whole-body ¹⁸F-FDG PET/CT and regional PET/MRI fusion images have complementary roles in the diagnosis of tongue NEC, and the former is mainly applied to determine the clinical stage of the disease and to guide treatment.     

Low-grade fibromyxoid sarcoma of the small bowel mesentery: computed tomography and magnetic resonance imaging findings

Low-grade fibromyxoid sarcoma (LGFMS) is a rare tumor that commonly arises in the lower extremities but rarely in the mesentery. We report computed tomography (CT) and magnetic resonance imaging (MRI) findings of LGFMS of the small bowel mesentery. On CT, the mass was composed of two components. One component, on its right side, appeared to have isointense attenuation relative to muscle, whereas the other component, on its left side, appeared to have low attenuation. On MRI the mass on the right side showed hypointensity similar to muscle on both T1-and T2-weighted images as well as mostly slight enhancement on contrast-enhanced T1-weighted images. On the other hand, the mass on the left side showed relative hypointensity on T1-weighted images and hyperintensity on T2-weighted images as well as intense enhancement on contrast-enhanced T1-weighted images, suggesting that the tumor contained myxoid tissue. The myxoid area of LGFMS may have a tendency to reveal intense enhancement on contrast-enhanced images.