Anti-Amphiphysin Stiff-Person Spectrum Disorders: A Systematic Review and Case Series Featuring an Unusual Isolated...

Area of Science:

• Neurology
• Oncology
• Immunology

Background:

• Anti-amphiphysin stiff-person spectrum disorders (SPSD) are paraneoplastic syndromes with limited data in Asian populations.
• This study presents two Asian cases and the largest pooled cohort analysis (n=64) of anti-amphiphysin SPSD.

Purpose of the Study:

• To describe the clinico-demographic features of anti-amphiphysin SPSD in an Asian cohort.
• To analyze the clinical presentation, malignancy association, and treatment outcomes of SPSD.
• To highlight the importance of early diagnosis and management, including for atypical presentations.

Main Methods:

• Case report of two Asian patients with anti-amphiphysin SPSD associated with breast adenocarcinoma.
• Pooled cohort analysis of 64 anti-amphiphysin SPSD cases from literature.
• Evaluation of clinical characteristics, stiffness distribution, malignancy prevalence, and treatment responses.

Main Results:

• Lower limbs were the most frequently affected site (82.2%), followed by upper limbs (57.8%).
• Malignancy was present in 93.8% of cases, predominantly breast (73.4%) or lung cancer (14.1%).
• SPSD symptoms preceded cancer diagnosis in 80% of cases; 56.8% achieved good functional outcomes (mRS ≤2), especially with "triple" therapy and oncological remission.

Conclusions:

• Anti-amphiphysin SPSD can have good outcomes with proper management, particularly when the underlying malignancy is treated.
• Atypical presentations, such as upper-limb stiff-limb syndrome, require high diagnostic suspicion.
• Early diagnosis and multimodal treatment (symptomatic, immunomodulatory, oncological) are crucial for favorable prognosis.