[Type 2 neurofibromatosis: intergenerational differences in genetic and clinical expression]. / Neurofibromatose de type 2 : différence inter-générationnelle d'expression génétique et clinique.

INTRODUCTION: Neurofibromatosis type 2 (NF2) is a rare dominantly inherited disease. Its clinical presentation can be completely different in children and adults and early diagnosis is often difficult. The NF2 gene molecular analysis can help for diagnosis, but its result can be negative in case of NF2 mosaicism. OBSERVATIONS: We report the case of a 43-year-old man who had developed a severe phenotype with bilateral vestibular schwannomas at 19 years of age. His son presented a retinal hamartoma with loss of vision in his right eye at 2 months of age. At 9 years of age, asymptomatic schwannomas of the cranial nerves were discovered: cranial nerves X (left), XI (left), and VIII (bilateral). Partial constitutional NF2 deletion (from exons 2-7) was detected in his son. The deletion was not detectable in the DNA blood of his father and we strongly suspect a mosaic form of NF2. CONCLUSION: Ophthalmological manifestations can be the initial sign of NF2 in childhood. These features must be actively sought during the first year of life in individuals at risk of NF2. NF2 mosaicism is often described as a mild form of NF2 with a very low risk of transmission to the carrier's children. We show that NF2 mosaicism can sometimes develop severe NF2 symptoms and we confirm that the transmission risk to the offspring depends on the proportion of zygotes carrying the mutation. NF2 remains a life-limiting and life-spoiling condition. Early diagnosis is necessary to prevent complications and the follow-up of NF2 patients must be organized throughout life in specialty centers.

Grading of small hepatocellular carcinomas (≤2 cm): correlation between histology, T2 and diffusion-weighted imaging.

OBJECTIVE: To evaluate the capacity of diffusion-weighted imaging (DWI) to determine the histological grade of small-sized hepatocellular carcinomas (HCCs) in liver cirrhosis in comparison with T2 weighted imaging. METHODS: 51 cirrhotic patients with 63 histologically proven HCCs ≤2 cm underwent abdominal MRI, including DWI (b-values 50, 400 and 800 s mm(-2)) and T2 weighted sequences. HCCs were classified into well-differentiated HCCs (n = 37) and moderately differentiated HCCs (n = 26). Relative contrast ratios (RCRs) between the lesions and the surrounding liver were performed and compared between the two groups for T2 weighted images, each b-value and apparent diffusion coefficients (ADCs). A receiver operating characteristic (ROC) analysis was performed to compare RCRs in T2 and diffusion-weighted images. RESULTS: We found significant differences in RCRs between well-differentiated vs moderately differentiated HCCs for b = 50, 400 and 800 s mm(-2) and T2 weighted images (1.35 ± 0.36 vs 1.86 ± 0.62; 1.35 ± 0.38 vs 1.82 ± 0.60; 1.27 ± 0.30 vs 1.74 ± 0.53; 1.14 ± 0.18 vs 1.43 ± 0.28, respectively; p < 0.001), whereas no significant differences were observed in ADC and ADC RCR (1.05 ± 0.19 vs 0.99 ± 0.15 and 1.1 ± 0.22 vs 1.09 ± 0.23; p = 0.16 and p = 0.82, respectively). No significant difference was found in the areas under the ROC curve for RCRs of T2 weighted images and every DWI b-value (p = 0.18). CONCLUSION: The RCR measurement performed in DWI 50, 400 and 800 b-values and T2 demonstrated a significant difference between well-differentiated and moderately differentiated small-sized HCCs. Furthermore, no difference was shown by using either ADC or ADC RCR. ADVANCES IN KNOWLEDGE: DWI with RCR measurement may be a valuable tool for non-invasively predicting the histological grade of small HCCs.

[Artery of Percheron occlusion: Value of MRI. A review of six cases]. / Occlusion de l'artère de Percheron : difficultés du diagnostic clinique et place de l'IRM. À propos de six cas.

Blood supply to the human thalami is complex and multiple variants exist. The artery of Percheron is one of those variants and is characterized by a solitary arterial trunk that branches from one of the proximal segments of either posterior cerebral artery and supplies blood to the paramedian thalami. Its occlusion results in bilateral paramedian thalamic infarction sometimes extending to the midbrain. We report six cases of bithalamic infarction secondary to occlusion of the artery of Percheron. We will illustrate the complex clinical symptomatology and underscore the role of imaging, especially MRI, for diagnosis.

[Brain abscess as the first clinical manifestation of isolated pulmonary arteriovenous malformation without Rendu-Osler disease]. / Abcès cérébelleux révélant une malformation artérioveineuse pulmonaire isolée en dehors de la maladie de Rendu-Osler.

INTRODUCTION: Brain abscesses occur in 5 to 13 % of patients with pulmonary arteriovenous malformation (PAVM), more often present in Rendu-Osler-Weber disease or hereditary hemorrhagic telangiectasia (HHT). CASE REPORT: A 51-year-old man with a history of transient Parinaud syndrome at 37 years complained of headache for 2 months before acute onset of a left cerebellar syndrome without fever. CT-scan and MRI of the head revealed a heterogeneous left cerebellar lesion. A brain abscess was drained and all signs resolved. CT-scan of the chest revealed a left lingual PAVM; occlusion was incomplete after coil embolization. He had no feature of HHT and no mutation in ENG and ACVRL1 genes. A second embolization was performed 5 months later, but the malformation was not occluded at 6 months. DISCUSSION: We report the seventh case of PAVM complicated by a cerebellar abscess. The right to left shunt in PAVM results in hypoxemia, secondary polycythemia and paradoxical embolization of infective organisms bypassing the pulmonary filter. CONCLUSION: Combining different MRI techniques (in particular diffusion and proton MR spectroscopy) provides invaluable data for the diagnosis of brain abscess. Careful search for PAVM must be undertaken, particularly in adults with cryptogenic abscess, to avoid further abscess formation or stroke.

[Susac syndrome: variable onset modes and disease courses: two case reports]. / Syndrome de SUSAC. Modes d'entrée et évolutions variables: à propos de deux cas.

INTRODUCTION: Susac syndrome is a rare microangiopathy of unknown etiology, which involves the clinical triad of encephalopathy, visual loss, and hearing loss. Several onset and progression patterns are possible. OBSERVATION: Case 1: a 43-year-old woman developed subacute encephalopathy, which had not been diagnosed and had been evolving for 2 months, as well as left sensorineural hearing loss. The fundus exam found central artery branch occlusion in the left retina. The treatment was based on corticosteroids combined with cyclophosphamide and immunoglobulins. Angiographic monitoring revealed persistent asymptomatic arterial alterations despite positive neurological progression. Case 2: a 27-year-old woman presented visual loss in the right eye after recurrent neurological episodes. The triad was completed by deafness in the right ear. Treatment with corticosteroids led to favorable neurological progression and stabilized the ophthalmologic symptoms. DISCUSSION: This syndrome preferentially affects young women. The nearly constant neurological symptoms can differ. Branch occlusions are frequently bilateral and often come with the appearance of vasculitis. Deafness is bilateral, asymmetrical, and of endocochlear origin. Brain MRI shows lesions of the corpus callosum that are distinctive of the syndrome. The disease mainly evolves in a monocyclic way, self-limited in time, and it rarely becomes chronic. Treatment, which has not been codified to date, is based on corticosteroids and, in severe cases, immunosuppressive drugs. Other therapies have not proved to be effective. CONCLUSION: The diagnosis is based on the triad of neurological, ophthalmic, and ENT damage, but sometimes it can be difficult to formulate because of the chronology of symptom onset. Neurological damage, the first manifestation, will help make therapeutic decisions.

Superior mesenteric artery syndrome: a rare etiology of upper intestinal obstruction in adults.

The superior mesenteric artery (SMA) syndrome is an atypical cause of high intestinal obstruction in adults. Formerly considered controversial, this syndrome has now been recognized as a real clinical entity which results from extrinsic compression of the third portion of the duodenum by reduction of the angle formed between the SMA and the aorta, usually favoured by rapid and dramatic weight loss. We report a case observed in a 25-year-old female. The abdominal scan provided the diagnosis. Laparoscopic duodenojejunostomy provided cure after failure of initial conservative treatment.

Common peroneal nerve palsy following TNF-based isolated limb perfusion for irresectable extremity desmoid tumor.

Hyperthermic isolated limb perfusion (ILP) (2 mg, TNF-alpha and 100mg, melphalan) was performed for an irresectable right thigh desmoid tumor with calf extension in a 49-year-old man. The patient had a history of four resections since the age of 19 years. Local ILP toxicity appeared with extensive edema and common peroneal neurologic impairment including paresis that remained severe 10 months later. One of the most troublesome side effects of perfusion is peripheral nerve damage, which has been reported at a rate of between 1 and 48% of perfused patients. ILP is an effective treatment in recurrence situations or where resection threatens loss of function; it, however, requires administration in specialized centers, progress in standardization and close monitoring to avoid locoregional toxicity, the mechanisms of which merit further investigation. Emergency compartmental pressure measurement may indicate fasciotomy, can be of great interest.