Neurological Disorders Associated with Striatal Lesions: Classification and Diagnostic Approach.

Neostriatal abnormalities can be observed in a very large number of neurological conditions clinically dominated by the presence of movement disorders. The neuroradiological picture in some cases has been described as "bilateral striatal necrosis" (BSN). BSN represents a condition histo-pathologically defined by the involvement of the neostriata and characterized by initial swelling of putamina and caudates followed by degeneration and cellular necrosis. After the first description in 1975, numerous acquired and hereditary conditions have been associated with the presence of BSN. At the same time, a large number of disorders involving neostriata have been described as BSN, in some cases irrespective of the presence of signs of cavitation on MRI. As a consequence, the etiological spectrum and the nosographic boundaries of the syndrome have progressively become less clear. In this study, we review the clinical and radiological features of the conditions associated with MRI evidence of bilateral striatal lesions. Based on MRI findings, we have distinguished two groups of disorders: BSN and other neostriatal lesions (SL). This distinction is extremely helpful in narrowing the differential diagnosis to a small group of known conditions. The clinical picture and complementary exams will finally lead to the diagnosis. We provide an update on the etiological spectrum of BSN and propose a diagnostic flowchart for clinicians.

Adult leukoencephalopathies with prominent infratentorial involvement can be caused by Erdheim-Chester disease.

BACKGROUND: Leukoencephalopathies with prominent involvement of cerebellum and brainstem, henceforward called prominent infratentorial leukoencephalopathies (PILs), encompass a variety of inherited and acquired white matter diseases. Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis likely under-diagnosed as cause of adult PIL. METHODS: We reviewed the clinical and laboratory information of ten consecutive sporadic adult patients with PIL of unknown origin, who were investigated for ECD. RESULTS: There were seven males and three females; mean age at clinical onset was 49.6 years (range 38-59); cerebellar ataxia with or without other neurological symptoms was the only or the main clinical manifestation; diabetes insipidus was present in three individuals. Eight patients had white matter focal supratentorial abnormalities, in addition to the infratentorial white matter changes. Six out of eight patients had spinal cord lesions. Thoraco-abdominal CT showed periaortic sheathing in two patients, whole-body FDG-PET revealed increased glucose uptake in the long bones of the legs in five patients, brain FDG-PET showed overt infratentorial hypermetabolism in one patient. In eight patients, ECD was confirmed by bone scintigraphy, pathological data, or both. Two ECD patients treated with vemurafenib showed a marked improvement of neurological symptoms and brain MRI abnormalities at 1 year follow-up. CONCLUSIONS: Symptoms of PIL can be the only clinical manifestation of ECD. Adult patients with PIL of unknown origin should undergo investigations aimed at unveiling ECD, including bone scintigraphy and whole-body FDG-PET. The early diagnosis allows starting disease-modifying therapies of an otherwise life-threatening disease.