Anti-amphiphysin-positive Progressive Encephalomyelitis with Rigidity and Myoclonus

• Published in: Canadian journal of neurological sciences 2023-09, Vol.50 (5), p.781-783
• Main Authors: Fujii, Yuki, Murata, Yuki, Hokkoku, Keiichi, Chiba, Takashi, Hamada, Yuichi, Uchibori, Ayumi, Chiba, Atsuro, Kobayashi, Shunsuke, Sonoo, Masahiro
• Format: Article
• Language: English
• Subjects: Antibodies; Breast cancer; Constipation; Electrodes; Encephalomyelitis; Hyperhidrosis; Letter to the Editor: New Observation; Magnetic resonance imaging; Remission (Medicine); Spinal cord; Tomography
• ISSN: 0317-1671; 2057-0155
• DOI: 10.1017/cjn.2022.293

Autoantibodies associated with SPS and PERM also overlap, but the prevalence of associated antibodies differs; specifically, anti-glutamic acid decarboxylase antibodies (anti-GAD) are most common in SPS, and anti-glycine-α1 receptor antibodies (anti-GlyR) are most common in PERM.1 Anti-amphiphysin antibodies are a marker of paraneoplastic SPS,2 but their association with PERM is rare; the clinical picture of anti-amphiphysin-positive PERM has not been well established.3–5 Diagnosis of PERM is often challenging because it is rare and shows unusual clinical symptoms, often lacking objective findings in conventional laboratory tests and imaging studies. The abnormalities are judged regarding the institutional normative values, which are body height adjusted, and expressed by the unit of standard deviations (SD).8 Four cases of anti-amphiphysin-positive PERM have thus far been reported, including the present case (Table 1).3–5 The cases showed core clinical signs of PERM and varying degrees of brainstem and spinal cord symptoms. In all reported anti-amphiphysin-positive PERM cases except our case, cancer developed within two years from the onset.3–5 SPSD associated with anti-amphiphysin is also at high risk (up to 90%) for malignancy, mostly breast cancer and small cell lung cancer, in contrast to SPSD with other antibodies (