Although imaging and clinical criteria are already established for the diagnosis of mucoid degeneration of the anterior cruciate ligament (ACL), many radiologists remain unaware of their existence. Once regarded as a rare occurrence, it has been recently suggested that its incidence is in fact very much higher than previously thought, and that it is probably underdiagnosed or misdiagnosed as partial ruptures of the ACL or as cystic ganglia. In this review, the authors revisit the literature concerning this subject and present their personal experience with it, stressing the paramount importance of magnetic resonance imaging and correlation with clinical data for a correct diagnosis.

Pseudotumoural hemicerebellitis is exceedingly rare. It may closely resemble a tumour either clinically or on imaging, and a high index of suspicion is required to avoid unnecessary surgical procedures. MRI is the most useful diagnostic tool, and reveals a swollen cerebellar hemisphere, hyperintense in T(2) weighted images. A pattern of predominantly pial contrast enhancement, absence of a well-defined mass and regression of the abnormalities in follow up examinations help to rule out malignancy. We report two cases of pseudotumoural cerebellitis (an 11-year-old girl and a 9-year-old boy) studied with CT and MRI.

The authors report a case of a 5 months old female child with clinical features of Aicardi syndrome: agenesis of the corpus callosum, occular abnormalities ("chorioretinal lacunae" and microphthalmus), infantile spasms, mental retardation, vertebral malformations and thoracic deformity. The pacient was submitted to complementary examinations that confirmed the diagnosis. The neuroradiologic images (MRI) showed besides corpus callosum agenesis a tumor located at the left ventricular atrium (choroid plexus papilloma). This association is a rare occurrence and the present case is the seventh described in literature. Furthermore, we suggest that the choroid plexus pappilloma could be a characteristic tumor of the Aicardi syndrome.

-Cavernous angiomas (cavernomas) of the cavernous sinus are uncommon, with only scattered reports in literature. Unlike their parenchymatous counterparts, they are intensely enhancing para-sellar masses, iso/hypointense in T1-and hyperintense in T2-weighted images. Differential diagnosis with parasellar meningiomas and schwannomas can be difficult. We report three cases of this condition, describing findings of diffusion-weighted imaging in this kind of lesion for the first time in literature.KEY WORDS: cavernous angioma, cavernous sinus, magnetic resonance imaging, computed tomography, angiography.Angioma cavernoso do seio cavernoso: achados aos exames de imagem RESUMO -Angiomas cavernosos (cavernomas) do seio cavernoso são lesões incomuns, com poucos relatos na literatura especializada. Ao contrário dos cavernomas parenquimatosos, são massas para-selares intensamente captantes, isointensas a hipointensas em T1 e hiperintensas em T2 nas imagens de ressonância magnética. O diagnóstico diferencial com meningiomas e schwannomas para-selares pode ser difícil. Relatamos os achados de imagem de três casos desta entidade, descrevendo os achados da ressonância magné-tica ponderada em difusão neste tipo de lesão pela primeira vez na literatura. PALAVRAS-CHAVE: angioma cavernoso, seio cavernoso, ressonância magnética, tomografia computadorizada, arteriografia.Cavernous angioma of the cavernous sinus is an extremely rare condition, and its differential diagnosis with tumors, namely para-sellar meningiomas and schwannomas, is often difficult. They are richly vascularized lesions, made up of a network of dilated, thin-walled vessels, and are responsible for less than one percent of all intracranial masses. The advent of magnetic resonance imaging (MRI) raised new diagnostic perspectives for this condition as we report in the study. METHODThis study was approved by the committee of Ethics of Clinica Radiologia Vila Rica, Brasilia DF, Brazil.Three female patients, with 42-years-old (patient 1), 45-years-old (patient 2) and 37-years-old (patient 3), are, respectively, presented with complaints of right-sided cranial nerves deficits (III nerve [patients 2 and 3], V1 nerve [patient 2] and VI nerve [patients 1 and 2]) and headaches. All of them underwent magnetic resonance imaging and cerebral digital subtraction angiography (DSA). Patients 2 and 3 were also submitted to computed tomography (CT). In all patients, MRI revealed well-delimited right para-sellar lesions, uniformly isointense in T1-weighted images and hyperintense in T2-, T2-and FLAIRweighted images, brightly enhancing after intra-vascular infusion of gadolinium. Diffusion-weighted sequence, performed in patient 3, revealed an isointense mass.

Introduction: Prolactinomas are preferentially treated with dopamine agonists. However, a few adenomas are resistant to this treatment.Objective: To evaluate the characteristics of patients with resistance to dopamine agonists in the long-term.Method: A retrospective study of six cases was made. Patients who did not achieve normalized prolactin blood concentrations and a reduction of more than 50% of the tumor volume with the minimum dose of 3.5 mg per week of cabergoline for 3 months or the maximum supported dose of bromocriptine for 6 months were considered resistant to dopamine agonists. Patients were followed up at the Clinic of Neurology and Endocrinology or the University Hospital of Brasilia.Results: Six patients were selected. Three patients were initially treated with bromocriptine prior to treatment with cabergoline. Four patients were men, and two were women. At the time of diagnosis, ages ranged from 9 to 62 years. Initial prolactin concentrations ranged from 430 to 14,992 ng/mL and in the last assessment ranged from 29.6 to 2,169 ng/mL. The tumor volume ranged from 0.77 to 24.0 mm3. Tumor regression occurred in all patients, ranging from 20 to 100%, but total disappearance of the adenoma with an empty sella occurred in one patient. The maximum weekly doses of cabergoline ranged from 3.0 to 4.5 mg. Follow-up time ranged from seven to 17 years. Normalization of prolactin concentrations occurred only in one woman after 17 years of treatment. Three patients also underwent surgery, but only one woman was cured of the disease.Conclusion: This study confirms that tumors resistant to dopamine agonists are more aggressive, since we did not have any microadenoma; treatment with high dose of cabergoline may reduce the size of the tumor without its disappearance, and that normalization of prolactin concentration rarely occurs. To our knowledge, this is the longest follow-up of a series of cases with resistance to dopamine agonists.