Pilocytic astrocytoma mimicking cavernous angioma: Imaging features and histological characteristics.

Pilocytic astrocytoma (PA) commonly occurs during the first two decades of life. Typical locations include cerebellum, optic nerve, optic chiasm/hypothalamus and brainstem. PA should be considered in the differential diagnosis of patients with brain tumors manifesting with hemorrhagic onset. We report a case of a hemorrhagic onset of cerebellar PA in a young adult with imaging findings mimicking cavernous angioma. We also discuss imaging features and histological characteristics with a focus on the etiology of the hemorrhagic onset.

MR imaging of intracranial hemangiopericytomas.

OBJECTIVE: To describe the MR features of primary intracranial hemangiopericytomas (HPCs) on conventional imaging, diffusion and MR spectroscopy and aim to determinate distinguishing features from meningiomas. METHODS: From 2006 to 2012, seven patients with pathologically confirmed primary intracranial HPCs were included. The clinical data, conventional MR findings (n=7), DWI features (n=7) and MR spectroscopy (n=5) were retrospectively analyzed. ADC values of the HPCs (n=7) were measured on ADC map and were compared with that of contralateral normal white matter. RESULTS: Of the seven HPCs, four were anaplastic HPCs (WHO grade III) and three were HPCs (WHO grade II). MR pattern consisted in lobulated or irregular margin tumors in all cases with cross-leaf growth on both side of the falx in two cases. The lesions showed mainly iso signal (n=4) on T1 WI and heterogeneous high signal (n=5) on T2 WI. Heterogenity was mainly related to intra tumoral hemorrhage (n=4), and proeminent intratumoral flow voids (n=3). Marked heterogeneous enhancement (n=5) with dural tail (n=4) was noted. All tumours showed significant peritumoral edema. ADC values of the tumor tissue component range between 0.638 and 1.50×10(-3)mm/s(2) (average = 1,02). Three grade II HPCs showed higher values compared to normal parenchyma ADC (range between 0.772 and 0.930×10(-3)mm/s(2) with average of 0.830), whereas grade III HPCs showed either equal (three cases) or decreased ADC values (one case). MRS showed in all cases markedly increased Cho with lip/lac peak, decreased Cr and almost absent NAA. High mI peak with large glutamine/glutamate were noted in the three grade II HPCs. CONCLUSION: Conventional MR pattern when combined with DWI and MRS findings are highly suggestive of HPC and appear valuable data to differentiate HPCs from meningiomas.

[Herpetic meningoencephalitis and acute disseminated encephalomyelitis: magnetic resonance imaging sequence]. / Méningo-encéphalite herpétique et encéphalomyélite aiguë disséminée : séquence en imagerie par résonance magnétique.

We report a case of herpetic encephalitis in a 2-year-old girl. Diagnosis was made at 1st by clinical symptoms and MRI and confirmed by lumbar puncture. Forty days later, new neurologic symptoms appeared and MRI diagnosed acute disseminated encephalomyelitis. MRI better demonstrates CNS abnormalities in herpetic encephalitis and may play a major role as a 1st step in early diagnosis, in particular for acute disseminated encephalomyelitis.

[Myositis ossificans circumscripta: the contribution of imaging]. / La myosite ossifiante circonscrite: apport de l'imagerie.

OBJECTIVES: Illustrate the specific and nonspecific aspects of myositis ossificans circumscripta (MOC) in standard imaging, cross-sectional imaging (sonography, CT, and MRI), and bone scintigraphy. PATIENTS AND METHODS: Eight patients presenting with MOC (three men and five women) were explored using standard radiography (eight cases), sonography (seven cases), scintigraphy (four cases), CT (six cases), and MRI (four cases). RESULTS: Standard x-rays and sonography of the soft tissue showed a well-defined mass containing calcifications in 75% of the cases. The CT scan diagnosed MOC in four cases, showing calcified masses separated from the adjacent bone by a clear radiotransparent border or afferent peripheral tumoral calcifications highly suggestive of MOC. MRI was nonspecific. Bone scintigraphy showed hyperfixation in the four cases imaged. CONCLUSION: Standard x-rays were useful to demonstrate the calcifications of MOC and to identify their relation with the subjacent bone. Sonography and bone scintigraphy were interesting in monitoring the lesion's maturation. In addition to early detection of calcifications, CT can precisely localize the lesion before surgical ablation. MRI is a very sensitive technique in detecting small lesions at an early stage, but it is nonspecific and does not remove the necessity of biopsy to eliminate the possibility of a malignant disease.

[Imaging of acute cerebellitis in children. Report of 4 cases]. / Imagerie des cérébellites aiguës chez l'enfant. A propos de 4 observations.

Acute cerebellitis is one of the main causes of acute cerebellar dysfunction in children. It is either infectious, usually viral, post-infectious or post vaccinal in etiology. Diagnosing acute cerebellitis may be difficult in patients with only subtle cerebellar signs and when cerebro-spinal fluid examination is normal. MRI is the most adequate imaging technique to demonstrate cerebellar involvement. The authors report the clinical and neuro-imaging findings in 4 paediatric cases. Patient's age varied from 2 to 7 years and predominant clinical symptoms were fever, headache and vomiting; ataxia was noted only in 2 cases. Viral serologic tests were negative in 3 cases and demonstrated Epstein-Barr virus in 1. Initial MRI examination (2 cases) demonstrated increased intensity on T2W and Flair sequences of the cerebellar gray matter with pial enhancement. Clinical outcome was good with complete resolution of symptoms in 3 cases and persistent mild right upper limb paresis in one. The resolution of the signal abnormality was well demonstrated on MRI in one case, suggesting an inflammatory etiology with moderate residual cerebellar atrophy.

[MR imaging in spinal cord injury]. / Apport de l'imagerie par résonance magnétique dans les traumatismes médullaires.

PURPOSE: To describe MR features of spinal trauma and assess the value of MR imaging in the prognosis. MATERIAL AND METHODS: Retrospective confrontation between initial and follow up MRI findings and clinical features in 7 young patients with spinal cord injury. RESULTS: Five lesions were due to motor vehicle accidents and 2 lesions were secondary to falls. Five patients had multiple associated injuries, 1 patient had associated spinal vertebrae injury, the last had Spinal Cord injury Without Radiological Abnormalities (SCIWRA). A motor deficit was noted in 5 cases of paraplegia, a case of monoplegia and a case of tetraparesia. The initial MRI showed in 3 cases intramedullary hemorrhage, cord edema in 2 cases and spinal cord compression and contusion in 1 case. Initial MRI was not done in the remaining case. No cord transection was noted. Outcomes were marked by lack of significant neurological recovery with complications due to bed confinement in 5 cases, and complete neurolgical recovery in two cases. In follow up, MR findings included post traumatic cystic lesion (2 cases), "ad integrum" restitution (1 case), segmental atrophy with gliosis (2 cases) and myelomalacia in the 2 other cases. CONCLUSION: MR may offer new possibilities in establishing the prognosis for neurological recovery. Our study demonstrated a good correlation between imaging findings, clinical features and outcomes. A hemorrhagic contusion in the acute stage indicated a poor prognosis while a focal hyperintense area on T2-weighted images may resolve.

[Atypic radiologic aspect of a renal cell carcinoma in children]. / Présentation radiologique atypique d'un carcinome à cellules claires du rein chez l'enfant.

Renal cell carcinoma is rare in children and is usually found in late childhood. The authors report on an exceptional case of renal cell carcinoma in a 10-year-old girl. The radiological aspect is misleading and has not been previously reported in the literature. Renal cortex was thin because of congenital megalo-ureter, so the tumor developed entirely into excretory cavities (to the proximal ureter), while a primitive urothelial disease (tumoral or inflammatory) was first evoked. The atrophied cortex was the tumoral starting point which prolapsed into excretory cavities, upraising the urothelial epithelium.

[Magnetic resonance imaging features of desmoplastic cerebral ganglioglioma of infancy: report of 1 case]. / Imagerie par résonance magnétique du gangliogliome desmoplastique infantile cérébral: à propos d'un cas.

Desmoplastic infantile ganglioglioma is a rare intracranial tumor of infancy, characterized by solid and cystic component, voluminous size and supratentorial location. These tumors are diagnosed usually below the age of 2 years. We report 1 case of desmoplastic ganglioglioma in 13-year-old male. Computed tomography and magnetic resonance imaging diagnosed supratentorial mixed cystic and solid tumor, which presented as a large cystic component with intense contrast enhancement of a mural nodule. The tumor was surgically removed, and histology revealed desmoplastic ganglioglioma. The patient had a good follow up. This observation emphasizes the possibility of desmoplastic ganglioglioma in older infants. It mustn't be considered as a specific entity of very young age infant and must be recognized in older infant because it may be misdiagnosed as malignant glioma. Despite the pseudo malignant appearance, these tumors have a good prognosis after surgery and when excision is complete they don't led to recurrences.

[Cerebral hydatid disease: imaging features]. / Hydatidose cérébrale: aspects en imagerie.

Cerebral hytatid cysts (HC) are extremely rare, forming 2% of all intra cranial space occupying lesions even in counties where the disease is endemic. HC diagnosis is usually based on a pathognomonic computed tomography (CT) pattern. In order to assess the value of MR we reviewed the CT (n=25) and magnetic resonance (MR, n=4 including diffusion and proton magnetic resonance spectroscopy in 1) imaging of 25 patients with pathologically confirmed cerebral hydatid disease. 19 HC were seen in children under 16 years. All were supra tentorial with 22 in the middle cerebral artery territory. HC was solitary in 18 cases, unilocular in 23 and multi-vesicular in 2 with heavily calcified pericyst in 1. 2 cysts were intra ventricular and 1 intra aqueducal. The most typical features were well defined, smooth thin walled spherical or oval cystic lesions of CSF density and/or signal with considerable mass effect (20/25). Surrounding oedema with complete or incomplete rim enhancement was seen in 3 cases which were labelled as complicated and/or infected cysts. Although CT is diagnostic of hydatid disease in almost all cases (22/25), MRI including diffusion and spectroscopy precisely demonstrate location, number, cyst capsule, type of signal and enhancement and allows diagnosis of atypical or complicated HC and appears more helpful in surgical planning.

[MRI findings in the diagnosis of pseudotumoral humeral hydatid]. / Apport de l'IRM dans le diagnostic d'une hydatidose humérale pseudo-tumorale.

Hydatidosis of bone is rare. Vertebral localizations predominate. Standard imaging may be misleading, suggestive of a malignant tumor or infection. We present the case of a patient with a humeral hydatid. This localization is very rare and presents an unusual radiographic aspect. Computed tomography produces an image suggestive of a tumor. The correct diagnosis can be established with MRI, particularly with the STIR sequence. In our patient, MRI enabled us to establish the diagnosis preoperatively and evaluate extension. MRI has been found to be highly contributive to the diagnosis of hydatidosis of bone and for assessment of intra- and peri-osseous extension.

[Hydatid cyst of soft tissues: MR imaging findings (Report of three cases)]. / Kyste hydatique des tissus mous: apport de l'IRM (A propos de trois observations).

Three cases of hydatid disease of the soft tissues are reported. All presented as soft tissue lesions in the neck and lower extremities. All three cases were studied with ultrasound (US) and magnetic resonance (MR) imaging techniques. Two patients presented with multivesicular lesions, which were considered diagnostic for hydatid disease. The third showed a lesion with hypoechoic solid and lobulated pattern mimicking lymph node. MR outlined the cystic pattern with intense peripheral enhancement and was suggestive of an infected cystic lesion. Surgery was performed in all three cases. Hydatid disease presenting in the soft tissues can be diagnosed with confidence, when US and/or MR shows multivesicular lesions. MR appears to be the most useful imaging technique when a complex or solid pattern is present. Enhancement of the peri-cystic soft tissues can be considered as a suggestive MR feature of soft tissue hydatid disease.

[Magnetic resonance imaging features of cystic meningiomas. Report of four cases]. / Aspects en imagerie par resonance magnetique des méningiomes kystiques. A propos de quatre cas.

Four cases of cystic meningioma are reported, and the imaging features and diagnostic pitfalls of cystic meningiomas are reviewed. Cystic meningiomas are infrequent tumors and remain difficult to diagnose in spite of advanced imaging techniques. Our patients were between 15 and 58 years of age, and underwent CT and MR imaging. In all the four cases, the meningiomas were supratentorial and included Nauta type I, type II and type III tumors.

[Esophageal mucocele: report of 2 pediatric cases]. / Mucocèle oesophagienne à propos de deux observations pédiatriques.

Two cases of esophageal mucocele in pediatric patients are reported: two children of 5 and 9 years respectively underwent surgical isolation of the esophagus and esophagocoloplasty for caustic stenosis related to accidental ingestion of caustic soda. Clinical pattern of mediastinal compression was proved with cervical fistulous tract in one case. In both cases, thoracic computed tomography was a sensitive imaging method to demonstrate the mucocele and its extension. Esophageal mucocele is rarely described in children, especially following esophageal corrosive stricture.

[Abdominal actinomycosis. Report of 4 clinical cases studied with radiography]. / Actinomycose abdominale. A propos de 4 observations radiocliniques.

We report 4 cases of pathologically proven abdominal actinomycosis. US and CT demonstrated an infiltrative abdominal mass with ill-defined margins and heterogeneous enhancement after IV contrast. The ileo-cecal region was involved in one case; the mass appeared following cholecystectomy and recurred 3 years after surgical resection in one case; and no predisposing factor was identified in the 2 other cases. In one of these, recurrence was observed 12 years after the first episode. Actinomycosis must be included in the differential diagnosis of invasive abdominal lesions with "malignant" appearance.

[Acute pyelonephritis and subcapsular hematoma revealing nephroblastoma at the age of 15 years]. / Pyélonéphrite aiguë et hématome sous-capsulaire révélant un néphroblastome à l'âge de 15 ans.

BACKGROUND: Nephroblastoma' the most common renal tumor in children between 1 and 5 years, occurs rarely in the oldest child. CASE REPORT: A 16-year-old teenager suffered from acute pyelonephritis caused by Klebsiella pneumoniae. Renal ultrasonography showed a left subcapsular hematoma; the CT scan confirmed the finding and also showed renal scarring. However, a second CT scan showed pulmonary nodules suggestive of metastasis, a diagnosis that was confirmed by needle biopsy of pulmonary lesions. Recovery was obtained after chemotherapy and nephrectomy with a 3-year-follow-up. CONCLUSION: This nephroblastoma was particular because its development in an adolescent, its association with acute pyelonephritis and subcapsular hemorrhage.

[Value of imaging in the assessment of malignant fibrous histiocytoma of the soft tissues]. / Place de l'imagerie dans le bilan des histiocytomes fibreux malins des parties molles.

Malignant fibrous histiocytoma (MFH) is a rare and potentially highly malignant sarcoma. The authors report 6 cases of MFH in various sites: two in the chest wall, one in the pelvis, two in the gluteal zones and one on the scalp. Ultrasonography and computed tomography were the main imaging methods used in the assessment of the structure and extension of the tumor. A poor prognosis was noted in four cases: death within a few months in the two thoracic sites, recurrence in the pelvic and scalp lesions, radical surgery allowed recovery in two cases. A review of the literature showed that MRI and CT are complementary in the initial staging and follow-up of these patients.