Posterior fossa arachnoid cysts in multiple system atrophy

Area of Science:

• Neuroscience
• Neurology
• Pathology

Background:

• Multiple System Atrophy (MSA) is a rare neurodegenerative disorder characterized by α-synuclein deposition in glial cells, leading to cerebellar and parkinsonian symptoms.
• The precise mechanism of α-synucleinopathy in MSA remains unclear.
• Posterior fossa arachnoid cysts are rare, benign fluid-filled sacs located in the posterior cranial fossa.

Purpose of the Study:

• To report on three patients presenting with posterior fossa arachnoid cysts who were subsequently diagnosed with clinically established Multiple System Atrophy (MSA).
• To explore the potential relationship, whether coincidental or mechanistically linked, between posterior fossa arachnoid cysts and MSA development.

Main Methods:

• Retrospective case series describing three patients with co-existing posterior fossa arachnoid cysts and MSA.
• Clinical presentation, diagnostic findings, and imaging results (including pontine and cerebellar atrophy) were analyzed.
• Statistical probability of the co-occurrence of both conditions was calculated assuming independence.

Main Results:

• Patients presented between 45-67 years with 2-3 years of progressive cerebellar symptoms and non-motor features (orthostatic hypotension, genitourinary failure, dream enactment behavior).
• All patients exhibited posterior fossa arachnoid cysts and imaging findings supportive of MSA, such as pontine and cerebellar atrophy.
• The calculated probability of the independent co-occurrence of MSA and posterior fossa arachnoid cysts is extremely low (1.09 e-6).

Conclusions:

• The co-existence of Multiple System Atrophy and posterior fossa arachnoid cysts in these three patients is statistically improbable by chance alone.
• While the concurrence is likely coincidental, the presence of space-occupying lesions like arachnoid cysts might potentially influence or accelerate neurodegenerative disease progression.
• Further research is warranted to investigate any potential shared underlying mechanisms or the impact of arachnoid cysts on neurodegeneration in MSA.