This is an interesting paper out of the Mayo Clinic Jacksonville about “four patients…with clinical features consistent with frontotemporal dementia (FTD), including two with corticobasal syndrome, one with progressive non-fluent aphasia, and one with behavioral variant FTD. None had autonomic dysfunction.”
Curiously, these four patients met the pathological criteria for multiple system atrophy (MSA). These were all atypical MSA cases because “[all] had frontotemporal atrophy and severe limbic α-synuclein neuronal pathology.”
The Mayo researchers note a previous case report of a woman with progressive dementia, psychosis, and muscular rigidity “with neuropathological features of both MSA and LBD” (Lewy body dementia). This could be a fifth case of atypical MSA with features of FTD.
Researchers also note that six other atypical MSA cases have been reported around the world.
They conclude:
“Atypical MSA does not fit into any of the current categories [of FTLD – frontotemporal lobar degeneration]. We propose a new category of FTLD for atypical MSA—FTLD-synuclein. Alternatively, atypical MSA could be considered a subtype of MSA in addition to MSA-P and MSA-C, namely MSA-FTD. From a clinical perspective, this is a more challenging diagnosis, since none of our patients carried an antemortem diagnosis of MSA; rather, the clinical picture was that of FTD.”
The abstract is copied below.
The things you learn via brain donation!
Robin
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Acta Neuropathologica. 2015 Jul;130(1):93-105. Epub 2015 May 12.
Atypical multiple system atrophy is a new subtype of frontotemporal lobar degeneration: frontotemporal lobar degeneration associated with α-synuclein.
Aoki N, Boyer PJ, Lund C, Lin WL, Koga S, Ross OA, Weiner M, Lipton A, Powers JM, White CL 3rd, Dickson DW.
Abstract
Multiple system atrophy (MSA) is a sporadic neurodegenerative disease clinically characterized by cerebellar signs, parkinsonism, and autonomic dysfunction. Pathologically, MSA is an α-synucleinopathy affecting striatonigral and olivopontocerebellar systems, while neocortical and limbic involvement is usually minimal. In this study, we describe four patients with atypical MSA with clinical features consistent with frontotemporal dementia (FTD), including two with corticobasal syndrome, one with progressive non-fluent aphasia, and one with behavioral variant FTD. None had autonomic dysfunction. All had frontotemporal atrophy and severe limbic α-synuclein neuronal pathology. The neuronal inclusions were heterogeneous, but included Pick body-like inclusions. The latter were strongly associated with neuronal loss in the hippocampus and amygdala. Unlike typical Pick bodies, the neuronal inclusions were positive on Gallyas silver stain and negative on tau immunohistochemistry. In comparison to 34 typical MSA cases, atypical MSA had significantly more neuronal inclusions in anteromedial temporal lobe and limbic structures. While uncommon, our findings suggest that MSA may present clinically and pathologically as a frontotemporal lobar degeneration (FTLD). We suggest that this may represent a novel subtype of FTLD associated with α-synuclein (FTLD-synuclein).
PMID: 25962793 (see pubmed.gov for the abstract only)