title: Primary giant cell tumor of soft tissue of the groin - a case of 46 years duration.
abstract: BACKGROUND
  Soft tissue giant cell tumor (GCT-ST) of low malignant potential is an uncommon neoplasm, considered the soft tissue counterpart of giant cell tumor of bone. GCT-ST mainly affects young to middle-age adults and presents as a painless growing mass mainly located in the lower extremities and trunk. Histologically, this tumor is characterized by a mixture of uniformly scattered osteoclast-like multinucleated giant cells intimately admixed with short fascicles of spindled cells. Complete excision with negative surgical margins is associated with a benign clinical course in most cases.
  
  
  METHODS
  The authors report the clinicopathological and immunohistochemical features of an unusual GCT-ST of 46 years duration previously histologically misdiagnosed as Kaposi's sarcoma.
  
  
  RESULTS
  Histologically, the tumor was characterized by a multinodular growth pattern with osteoclast-like multinucleated giant cells admixed with spindle cells partially arranged in a storiform pattern, fibrosis and foci of haemorrhage and mature bone. Immunohistochemistry revealed CD68 reactivity of the multinucleated giant cells.
  
  
  CONCLUSIONS
  GCT-ST is a rare neoplasm characterized by benign clinical course if excised adequately, as shown by our case of exceptionally long duration. Emphasis is placed on the importance of differential diagnosis with other giant cell-rich soft tissue neoplasms because clinical behaviour, prognosis and treatment significantly differ.
authors.affiliation: Institute of Dermatological Sciences, University of Milan, Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milan, Italy.
authors.forename: Vinicio
authors.initials: V
authors.lastname: Boneschi
authors.forename: Antonina
authors.initials: A
authors.lastname: Parafioriti
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Armiraglio
authors.forename: Francesca
authors.initials: F
authors.lastname: Gaiani
authors.forename: Lucia
authors.initials: L
authors.lastname: Brambilla
mesh_terms: D017668:Age of Onset; D000368:Aged; D015703:Antigens, CD / Q000096:biosynthesis; D015214:Antigens, Differentiation, Myelomonocytic / Q000096:biosynthesis; D001706:Biopsy; D003951:Diagnostic Errors; D005870:Giant Cell Tumors / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D006119:Groin / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D012514:Sarcoma, Kaposi / Q000175:diagnosis; D012983:Soft Tissue Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; C067980:CD68 antigen, human; D000097382:CD68 Molecule