Nodular Fasciitis on the Nasolabial Fold in a 5-month-old Infant: A Case Report

We report the case of a 5-month-old infant with a rapidly growing mass on the right nasolabial fold; to our knowledge, this is the youngest infant diagnosed with nodular fasciitis in the literature. Based on the anatomic location, this was a subcutaneous type of nodular fasciitis and it had a mixed cellular and fibrous histologic composition, which is rare in infancy. Here we present periodic ultrasonographic images and MR images, as well as a detailed comparison of the pathologic and radiologic findings.

Radiological Findings of Pilomatricoma: Case Report

Pilomatricoma is a rare benign neoplasm arising from the outer sheath of hair follicles. A firm, freely movable, and well-circumscribed subcutaneous nodule is a characteristic clinical feature of pilomatricoma. Diagnosis is usually based on clinical features, and surgical excision is performed without the use of imaging. Radiological evaluation has been used primarily as a means for differentiating pilomatricoma from other tumors or inflammatory conditions and also for examining unusually large or aggressive tumors. As a result it is important to be familiar with radiological characteristics of pilomatricoma. In this report, three cases of pilomatricoma from a pool of 28 pathologically confirmed cases are examined. Characteristic radiological findings of pilomatricoma are well-defined, oval shaped subcutaneous nodules adherent to the overlying skin with various amounts of calcification on plain radiography, CT scan, and ultrasound.

Pleuropulmonary Blastoma: A Case Report

Primary pulmonary neoplasms are uncommon in children. One such tumor, pleuropulmonary blastoma (PPB), is very rare, highly aggressive and malignant, and originates from either the lungs or pleura. It contains both mesenchymal and benign epithelial elements that resemble fetal lung, and occurs mainly in children aged less than five. The clinal symptoms often suggest upper respiratory tract infection or pneumothorax, but ultrasonography and chest CT scans depict both a large mass occupying an almost entire hemithorax, and a simple lung cyst. Contrast-enhanced CT demonstrates hetergeneous attenuation and a whorled appearance.

Congenital Bilateral Neuroblastoma (Stage IV-S): Case Report

Congenital neonatal neuroblastoma is not uncommon but bilateral adrenal neuroblastoma is rare, accounting for about ten percent of neuroblastomas in children. We report the US and MR findings of a stage IV-S congenital bilateral neuroblastoma occurring in a one-day-old neonate.

MR and CT Findings of Temporal Bone Langerhans Cell Histiocytosis

PURPOSE: To describe the MRI and CT findings of temporal bone Langerhans cell histiocytosis. MATERIALS AND METHODS: The MRI (n=8) and CT (n=7) findings of nine lesions of temporal bone Langerhans cell histiocytosis in six children were retrospectively reviewed. Eight lesions were pathologically confirmed and one was clinically diagnosed. The findings were analyzed for bilaterality, location, lesion extent, signal intensity, the attenuation of soft tissue lesions seen at MRI or precontrast CT, enhancement pattern at MRI or CT, and the pattern of bony destruction at CT. RESULTS: Bilateral involvement was present in three of six patients (50%). Lesions were most frequently located in the mastoid (n=8, 89%), followed by the petrous ridge (n=6, 67%), and the squamous portion (n=3, 33%). Seven (78%) lesions extended to the ipsilateral cavernous sinus (n=3), sphenoid bone (n=3), orbit (n=2), or epidural space (n=2). The signals of the soft tissue lesions were isointense in five cases (63%) on T1-weighted images and hyperintense in six (75%) on T2-weighted images. Five lesions (71%) were isodense on precontrast CT scans. The enhancement patterns were inhomogeneous in six cases (75%) at MRI, and homogeneous in five (71%) at CT. All lesions demonstrated bony destruction without periosteal reaction and five (71%) showed ill-defined destruction, with crossing sutures. CONCLUSION: Familiarity with findings of predominant mastoid involvement, isointense or isodense soft tissue lesions seen on T1-weighted images or at precontrast CT, with relatively homogeneous enhancement at CT, and irregular bony destruction with crossing sutures may be helpful in narrowing the diagnosis of temporal bone Langerhans cell histiocytosis.

Embryonal Rhabdomyosarcoma of the Posterior Mediastinum: A Case Report

A rhabdomysarcoma originating during childhood is an easily-detected soft tissue sarcoma which frequently occurs in the head, and neck, or genitourinary system. It has been reported that in the mediastinum its rate of occurrence is 1 percent, though the rate at which it occurs in the posterior mediastinumhas not been reported. We recently encountered a case of embryonal rhabdomyosarcoma of the posterior mediastinum in a 12-year-old girl with neurofibromatosis type 1. Initial chest X-rays revealed a well-marginated round mass, with destruction of the right posterior rib. CT scans indicated the presence of an iso-dense mass which after contrast infusion showed heterogeneous enhancement. T1-and T2-weighted MR images showed, respectively, slight and heterogenous hyperintensity, with invasion of the thoracic spine and compression of the spinal cord. After surgery, embryonal rhabdomyosarcoma of the posterior mediastinum was pathologically confirmed.

Congenital Glioblastoma Multiforme: A Case Report

Congenital glioblastoma multiforme is relatively rare accounting for 2-9% of all congenital brain tumors. We deseribe a case of congenital glioblastoma multiforme which occurred in the lateral ventricle. T1-weighted images revealed high signal intensity, with areas of internal low signal intensity, while T2-weighted images showed low signal intensity with focal internal high-signal portions. Post-contrast T1-weighted images depicted a lateral ventricular mass which extended to adjacent brain parenchyme and had a serpentine signal void representing internal vessel.

CT Findings of Orbital Langerhans Cell Histiocytosis

PURPOSE: To evaluate the CT findings in patients with Langerhans cell histiocytosis (LCH) involving the orbit. MATERIALS AND METHODS: Orbital CT scans of six children with pathologically proven LCH were retrospectively analyzed. Follow-up CT (n = 5) and MR (n = 1) imaging findings were also revi ewed. RESULTS: Initial CT scans revealed varying degree of bone destruction with soft-tissue masses, and on nonenhanced images the mean attenuation value was 44 Hounsfield units(HU). All masses showed mild to moderate enhancement with a mean attenuation value of 74 HU. The bony margins abutting onto soft tissue masses were irregular but clearly demarcated. No evidence of calcification or periosteal reaction was noted. Suprasellar mass and rib involvement was noted in one patient and hepatos-plenomegaly in two. Follow-up CT and MR images showed that the soft tissue masses were almost completely resolve d, with bone remodeling and reossification. CONCLUSION: A soft tissue mass with irregular but clearly demarcated bone destruction is thought to be a characteristic finding of LCH involving the orbit. Follow-up images after treatment showed bone remodeling and reossification.

Postoperative Meningeal Enhancement on MRI in Children with Brain Neoplasms

The meninges composed of the dura, the arachnoid and the pia are significant sites of blood-brain barrier. Physical disruption of the integrity of the meninges from avariety of causes including surgery results in various patterns of meningeal enhancement on contrast enhanced MR images. It is important to distinguish normal reactive or benign postoperative enhancement from more serious leptomeningeal metastasis or infection, particularly in children with intracranial neoplasms. We present various pat-terns of meningeal enhancement on MRI in children following surgery for brain neop lasms.

Pancreatic Mucinous Cystadenocarcinoma in an 11-year-old Girl: A Case Report

Mucinous cystic neoplasms of the pancreas are uncommon and known to occur mainly in middle-aged women. Wepresent a case of pancreatic mucinous cystadeno-carcinoma in an 11-year-old girl who had a past history of bluntabdominal trauma. The tumor was initially mistaken for a traumatic pseudocyst. US and CT revealed a multiloculatedcystic mass in the pancreatic tail. The mass showed good transmission on ultrasonography (US) and had anattenuation value of 10 HU on CT. Metastatic lesions in the liver were also shown on follow-up study.

Rhabdomyosarcoma of Children in the Head and Neck: CT and MR Findings

PURPOSE: To evaluate radiologic findnings of rhabodmyosarcoma of children in the head and neck concerning theorigin, morphologic characteristics, extent, and the route of intracranial extension on CT and MR. MATERIALS AND METHODS: Twenty cases of pathologically proven rhabdomyosarcoma were analyzed. Fifteen CT scans (postcontrast CT(n=13), precontrast CT (n=2)) and eleven MR scans were obtained. Postcontrast MR scans were performed in the tencases. Six cases had CT and MR scans. Nine cases had only CT scan and five had only MR scans. We retrospectivelyanalyzed the origin, morphologic characteristics (attenuation, signal intensity, margin), extent, intracranialextension, route and clinical staging of rhabdomyosarcoma on CT and MR scans. RESULTS: Out of the twentyrhabdomyosarcomas, sixteen cases were of parameningeal group. Ten cases of parameningeal group located in theinfratemporal fossa which was the most common site of origin. The mass showed iso-density in the 8 cases (62%) andhigh density in the 5 cases (38%) on the postcontrast CT scans compared with the muscle. All cases on the CT scanshowed homogenous attenuation of the tumor except one which showed internal necrosis. Twelve cases (80%) on preandpostcontrast CT scans (n=15) showed moderately-defined margin and the rest showed ill-defined margin. On MR scans,all the cases (n=11) showed iso- and high signal intensity on T1WI and T2WI, respectively. Strong enhancement ofthe mass was seen in all cases (n=10). Nine cases showed homogenous signal intensity of tumor on pre-andpostcontrast MR scan while 2 cases showed inhomogenous signanl intenisty because of hemorrhage(n=1) andnecrosis(n=1). Therefore the margin of rhabdomysarcoma on all pre-and postcontrast MR scans was well-defined. Theextent of rhabdomyosarcoma was various depending on corresponding origin and parameningeal group showed widerextent than other head and neck group. Infratemporal rhabdomyosarcoma showed expansile growth and intracranialextension via foramen ovale. Those in the middle ear invaded intracranium by directly destoying petrous bone andvia internal auditory canal. Those in the nasal cavity extended into intracranium by directly destroying skullbase of frontal lobe. Nasopharyngeal one extended into intracranium mainly by directly destroying base of skull orpartially via foramen ovale. Clinical Stage 1,2 and 3 were one, four and fifteen cases, respectively. CONCLUSION: Rhabdomyosarcoma of children in the head and neck tends to show relatively severe bony destruction of skull baseand various intracranial extension routes can be helpful radiologic findings on the CT or MR scan although its CTdensity or signal intensity of MR was not specific. And it is peculiar that infratempral fossa was the most commonsite of origin of rhabdomyosarcoma.

Intra-abdominal Desmoplastic Small Cell Tumor in a Girl: A Case Report

PURPOSE: To review MRI in order to compare Gd-DTPA enhanced images before and after preoperative intraarterialchemotherapy for osteosarcoma. MATERIALS AND METHODS: In sixteen patients with pathologically-proven osteosarcomawho underwent intra-arterial chemotherapy, MR images were obtained before and after this treatment. The degree[grade 0(low) to IV(high)] and pattern (homogenous, inhomogenous) of changes in contrast enhancement and tumorsize were evaluated. RESULTS: Enhancement changed from Grade III to I in eight patients and from Grade III to IIin five. In three, the enhancement pattern changed from homogenous to inhomogenous; in ten, the inhomogenouspattern did not change; and in three, there was a change from thick, irregular to thin, smooth-rimmed enhancement.In all patients except one, the intraosseous tumor component was not changed. The extraosseous component becamelarger in three patients, smaller in two, and showed no size change in eleven. CONCLUSION: In osteosarcoma, MRimaging after Gd-enhancement following intra-arterial chemotherapy showed decresased enhancement, and increasedinhomogeneity and smooth rim enhancement. Neither the intra-nor extraosseous tumor component showed size changewith time.

CT Findings of Hepatoblastoma Before and After Chemotherapy: Correlation with Pathologic Features

PURPOSE: The purpose of this study was to analyze the CT findings of hepatoblastoma before and afterchemotherapy, and to compare them with surgical and pathologic features. MATERIALS AND METHODS: Twelvehepatoblastoma patients underwent chemotherapy prior to surgery; in all cases, CT scanning was performed beforeand after chemotherapy. We reviewed the findings with special attention to changes in tumor volume, the extent andpattern of contrast enhancement, the extent of low-attenuation area in the tumor, the presence of a septum, andcalcification or ossification within the mass before and after chemotherapy. Post-chemotherapy CT findings werecompared with operative and pathologic findings. RESULTS: After chemotherapy, the volume of the tumor massdecreased in all patients, and the extent of involved segments decreased in nine(75%), the non-enhancing areawithin the mass, on the other hand, increased in nine (75%). On pre-chemotherapy CT, calcifications were detectedin seven patients(58%), and on post-chemotherapy CT, in nine (75%); the extent of calcification increased in sevenpatients. On the basis of CT findings, viable tumor and necrosis areas could not be distinguished. Massivecalcification or an osteoid mixed with loose connective tissue was noted in the mesenchymal component of thetumor; the whirling pattern of enhancement within the area of low density asen on CT scanning corresponded toosteoid mixed with loose connective tissue, which contained rich blood vessels. CONCLUSION: We describe the CTfindings of hepatoblastoma both before and after chemotherapy, highlighting the changes which occurred. Anunderstanding of these changes is helpful for the proper management of this condition.

Sacrococcygeal Germ Cell Tumors: Differential Features between Benignancy and Malignancy on MR and CT Imaging

PURPOSE: The purpose of this study was to determine differential points between benign and malignants acrococcygeal germ cell tumors (SGCT) on MR and CT imaging. MATERIALS AND METHODS: MR (n=13) and CT images (n=9)of 19 patients with surgically-proven SGCT (12 benign, 7 malignant) were retrospectively reviewed with regard totumor features and associated findings, as well as to clinical features including age at presentation and ratio of the sexes. Tumor features in cluded location, size, components (ratio of the enhancing solid portion, presence of fatty components, calcification and necrosis), signal intensity and the presence of an encircling low-signal rimon MR. Associated findings included the presence of sacrococcygeal bony defect and effects of the tumor on adjacent structures (anterior displacement of the bladder and rectum, local invasion). RESULTS: Benign SGCT showed early presentation (mean age, 4.7months), a predominantly (over half total volume) external location(58%)and a cystic composition(100%) and the presence of encircling low-signal rim on MR(80%). Malignant SGCT showed late presentation beyond infancy(mean age, 21.7months), a predominantly internal location(86%) and a enhancing solid composition(86%), the presence of tumoral necrosis(71%) and local invasion of adjacent structures(71%). The significant(p<.05) differential points were age at presentation, location, ratio of enhancing solid portions, the presence of tumoral necrosis, the presence of an encircling low-signal rim on MR and local invasion. CONCLUSION: There are certain differential points between benign and malignant SGCT on MR and CT imaging, and an appreciation of these would be helpful for the planning of treatment.