title: Immunophenotypic analysis of glomus coccygeum associated with coccygodynia.
abstract: OBJECTIVE
  Glomus coccygeum is a glomus body which is found in the pericoccygeal soft tissue. This specialised arteriovenous anastomosis is a non-pathological vestigial structure usually larger than its equivalent in the distal extremities. Its prevalence is uncertain. Glomus coccygeum has been associated with coccygodynia and can cause diagnostic problems to pathologists unfamiliar with this entity.
  
  
  METHODS
  The presence of a glomus coccygeum was sought in 40 coccygectomy specimens and correlated with clinical, radiological and histological findings.
  
  
  RESULTS
  A glomus coccygeum was identified in 13 samples (35%). Glomus cells expressed smooth muscle actin (SMA) and were negative for desmin, S100, cytokeratin and a wide range of vascular markers. Proliferative activity was low. Pre-operative MRI did not identify these tiny lesions, and most patients with coccygodynia did not have a glomus coccygeum.
  
  
  CONCLUSIONS
  Glomus coccygeum is a common microanatomical structure which can be distinguished from glomus and other tumours by its small size, SMA expression and low proliferative activity.
authors.affiliation: Department of Pathology, Nuffield Department of Orthopaedics, University of Oxford, Nuffield Orthopaedic Centre, Oxford, UK.
authors.forename: Francesca
authors.initials: F
authors.lastname: Maggiani
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kashima
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Ostlere
authors.forename: Nick A
authors.initials: NA
authors.lastname: Athanasou
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003050:Coccyx / Q000473:pathology* / Q000601:surgery; D005260:Female; D005918:Glomus Tumor / Q000737:chemistry / Q000175:diagnosis / Q000276:immunology / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000032:analysis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology*; D012445:Sacrococcygeal Region; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000175:diagnosis / Q000276:immunology / Q000473:pathology*; D055815:Young Adult
chemical_list: D007381:Intermediate Filament Proteins