title: Morphological and immunohistochemical evaluation of ganglion cysts. Cross-sectional study of 354 cases.
abstract: The aim of this study was to characterize the morphology and immunophenotype of ganglion cysts (GCs) and explore their histogenetic origin.
  
  
  
  A cross-sectional morphological and immunohistochemical study of 354 GCs used the following antibody panel: vimentin, specific actin, β-actin, smooth-muscle actin, smoothelin, h-caldesmon, β-catenin, desmin, calponin, podoplanin, keratins 5/6, E-cadherin, cyclooxygenase 2 (COX-2), lysozyme, CD10, CD31, CD33, CD34, CD68, Ki-67, and PCNA. Double-blind semi-quantitative analyses were conducted to evaluate the immunopositivity on a 4-point scale. Samples from 10 synovial membranes and 10 scapholunate ligaments were compared. GCs showed a hyalinized wall with mesenchymal spindle cells and were intensely positive for vimentin, actins, h-caldesmon, calponin in all cases and for podoplanin in 53% of cases, suggesting features of early muscle differentiation, without ruling out a myofibroblastic origin. Focal cavity lining of non-synovial flat or raised cells (CD34/CD31/CD10/E-cadherin-negative and podoplanin-positive in 34% of cases) was detected in 93% of cases, showing differential expression with synovial membrane and scapholunate ligament cells. Nuclear positivity for proliferative markers was observed in GC wall cells (258.1±255; 1019.3±316 positive cells/mm², Ki-67 and PCNA, respectively) but positivity for these markers was significantly lower (p⟨0.001 Mann Whitney U-test) in scapholunate ligament samples.
  
  
  
  In this first immunohistochemical study of GCs, focal cellular lining of the cavity was observed in almost all cases, and the immunophenotype was identical to that of GC wall cells. These cells are immunohistochemically different from synoviocytes and scapholunate ligament cells and show characteristics of myofibroblasts or mesenchymal cells undergoing early muscle differentiation.
authors.affiliation: Department of Pathology, San Cecilio Clinical Hospital, IBIMER and University of Granada, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: O'Valle
authors.affiliation: Department of Traumatology and Orthopaedic Surgery, San Cecilio Clinical Hospital and University of Granada, Spain. hdezcp@hotmail.com.
authors.forename: Pedro
authors.initials: P
authors.lastname: Hernández-Cortés
authors.affiliation: Department of Pathology, San Cecilio Clinical Hospital, IBIMER and University of Granada, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Aneiros-Fernández
authors.affiliation: Department of Pathology, San Cecilio Clinical Hospital, IBIMER and University of Granada, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Caba-Molina
authors.affiliation: Department of Pathology, San Cecilio Clinical Hospital, IBIMER and University of Granada, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Gómez-Morales
authors.affiliation: Department of Pathology, San Cecilio Clinical Hospital, IBIMER and University of Granada, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Cámara
authors.affiliation: Department of Pathology, San Cecilio Clinical Hospital, IBIMER and University of Granada, Spain.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Payá
authors.affiliation: Department of Pathology, San Cecilio Clinical Hospital, IBIMER and University of Granada, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Aguilar
authors.affiliation: Department of Pathology, San Cecilio Clinical Hospital, IBIMER and University of Granada, Spain.
authors.forename: Raimundo G
authors.initials: RG
authors.lastname: del Moral
authors.affiliation: Department of Pathology, San Cecilio Clinical Hospital, IBIMER and University of Granada, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Aneiros
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002454:Cell Differentiation; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D045888:Ganglion Cysts / Q000209:etiology / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D017746:Joint Capsule / Q000378:metabolism / Q000473:pathology; D008022:Ligaments / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D058628:Myofibroblasts / Q000378:metabolism / Q000473:pathology; D013314:Stress, Mechanical; D013583:Synovial Membrane / Q000378:metabolism / Q000473:pathology; D055815:Young Adult