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Immunotherapy‐refractory vacuolar myopathy with mucin deposition in scleromyxedema: A possible role of fibroblast growth factor 2
Author(s) -
Yanagihara Yuki,
Hayashi Shintaro,
Koge Junpei,
Honda Hiroyuki,
Yamasaki Ryo,
Yamada Yuichi,
Oda Yoshinao,
Iwaki Toru,
Kira Junichi
Publication year - 2020
Publication title -
neuropathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.701
H-Index - 61
eISSN - 1440-1789
pISSN - 0919-6544
DOI - 10.1111/neup.12659
Subject(s) - refractory (planetary science) , mucin , myopathy , immunotherapy , cancer research , medicine , biology , pathology , cancer , astrobiology
Scleromyxedema (SME) is characterized by widespread waxy papules on the skin, with mucin deposits in the upper dermis. Twenty‐one SME cases of myopathy have been reported; of the cases, six showed vacuolar formation, and two showed mucin deposition. We report the first case of SME with mucin‐associated vacuolated fibers. A 45‐year‐old woman with SME developed progressive proximal muscle weakness. Muscle biopsy revealed myopathic changes with numerous vacuoles linked to mucin in the affected muscle fibers, which were heavily immunostained for fibroblast growth factor 2 (FGF2). Despite repeated high dose oral prednisolone and intravenous immunoglobulin administrations, muscle weakness recurred continuingly, culminating in death due to congestive heart failure. Immunotherapy was partly effective in our case, although it was refractory. Treatment responsiveness in patients with SME myopathy varied; however, due to its rarity, the mechanism remains to be elucidated. To address this issue, we investigated muscle specimens immunohistochemically and detected marked upregulation of FGF2 in the affected muscle fibers of our patient. FGF2, a strong myogenesis inhibitor, may exert a suppressive effect on muscle fiber regeneration, which may have conferred refractoriness to our patient's SME myopathy.