title: Fibrosis, adipogenesis, and muscle atrophy in congenital muscular torticollis.
abstract: In the traditional view, muscle atrophy and interstitial fibrosis were regarded as the basic pathological features of congenital muscular torticollis (CMT). But in the ultrastructure study, the mesenchyme-like cells, myoblasts, myofibroblasts, and fibroblasts were found in the proliferation of interstitium of CMT. To investigate the characteristics of pathological features and the mechanisms of muscle atrophy in CMT, we retrospectively reviewed the medical records of 185 CMT patients from July 2009 to July 2011 in Shenzhen Children's Hospital in China and performed pathological studies. According to age, the 185 CMT patients were divided into 4 groups. All resected surgical specimens were processed for hematoxylin and eosin staining and Masson trichromic staining. Sudan III staining was used for frozen sections, whereas immunohistochemical staining for S-100, calpain-1, ubiquitin, and 20S proteasome was carried out on 40 CMT specimens. Eight adductor muscle specimens from 8 patients with development dysplasia of the hip were taken as control group in the immunohistochemical staining. By Masson trichromic staining, the differences in the percent area of fibrous tissue in each CMT groups were significant. In Sudan III staining and immunostaining for S-100, adipocyte hyperplasia was the pathological feature of CMT. Moreover, compared with controls, most atrophic muscle fibers in CMT specimens were found to show strong immunoreactivity for calpain-1, ubiquitin, and 20S proteasome. With increasing age, fibrosis peaked at both sides and it was low in middle age group. Adipocytes increased with age. The characteristics of pathological features in CMT are changeable with age. The calpain and the ubiquitin-proteasome system may play a role in muscle atrophy of CMT. In the CMT, adipogenesis, fibrogenesis, and myogenesis may be the results of mesenchyme-like cells in SCM (sternocleidomastoid muscle). In conclusion, the present study furthermore supports maldevelopment of the fetal SCM theory for etiology of CMT.
authors.affiliation: From the Zunyi Medical College Zhuhai Campus, Zhuhai (H-XC); Department of Pediatric Orthopaedics (S-PT, F-TG, J-LX, G-BF, KS, S-ZL, WS); and Department of Pediatric Pathology, Shenzhen Children's Hospital, Shenzhen, China (X-PJ, JC).
authors.forename: Huan-Xiong
authors.initials: HX
authors.lastname: Chen
authors.forename: Sheng-Ping
authors.initials: SP
authors.lastname: Tang
authors.forename: Fu-Tang
authors.initials: FT
authors.lastname: Gao
authors.forename: Jiang-Long
authors.initials: JL
authors.lastname: Xu
authors.forename: Xian-Ping
authors.initials: XP
authors.lastname: Jiang
authors.forename: Juan
authors.initials: J
authors.lastname: Cao
authors.forename: Gui-Bing
authors.initials: GB
authors.lastname: Fu
authors.forename: Ke
authors.initials: K
authors.lastname: Sun
authors.forename: Shi-Zhe
authors.initials: SZ
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
mesh_terms: D050156:Adipogenesis; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005355:Fibrosis / Q000209:etiology; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D009133:Muscular Atrophy / Q000209:etiology* / Q000473:pathology*; D009334:Neck Muscles / Q000473:pathology*; D012189:Retrospective Studies; D014103:Torticollis / Q000150:complications / Q000151:congenital* / Q000473:pathology