Multiple system atrophy-mimicking conditions: Diagnostic challenges.

Multiple system atrophy (MSA) is a relentless progressive disorder without effective treatment. Its accurate diagnosis is important for the management of individual patients and for the development of new therapeutic strategies. However, there are many disorders which can mimic MSA (so-called 'MSA look-alikes'), and the true rate for over- or under-diagnoses of MSA is not known, especially during the early course of disease when the disease is not fully developed yet. Herein, the authors review the neurodegenerative, genetic, and immunologic conditions that can mimic MSA and thus be part of the differential diagnosis of MSA. Clinicians should be aware of these conditions and be able to differentiate them by clinical features and laboratory findings.