title: [Tenosynovial giant cell tumor].
abstract: Morphological, ultrastructural, and immunohistochemical findings of 12 diffuse type-tenosynovial giant cell tumors/pigmented villonodular synovitis are presented compared to 30 localized tenosynovial giant cell tumors (giant cell tumor of tendon sheath). Diffuse-type-tenosynovial giant cell tumor is characterized by a striking vascularisation pattern composed of densely arranged thin-walled, partly slit-like and partly hyalinized small blood vessels within the papillary synovial fronds. These vessels may show abnormal structures with incompletely arranged endothelial cells/pericytes. The fibrohistiocytic tumor cells probably cause considerable compression/distortion or destruction of the small vessels which might be responsible for an increased blood deposition and massive hemosiderosis. Accompanying multinucleated osteoclast-like giant cells seemingly are recruited from circulating blood monocytes. Microhemorrhagic foci with multinucleated giant cells could be detected in 83% of diffuse-type and 67% of localized-type tumors. Apart from the described vessels, typical morphological findings in diffuse-type tenosynovial giant cell tumors included "giant" hemosiderotic granules, (at least 2-3 times the diameter of an erythrocyte) "giant" siderophages, pseudoalveolar clefts and irregularly anastomosing synovial fronds. Neither mitotic rate nor the amount of giant cells/amount of nuclei of giant cells revealed statistically significant differences between localized-type and diffuse-type of tenosynovial giant cell tumor. Immunohistochemically, the diffuse-type exhibited focal expression of CD31 (in 75% of tumors) and calretinin (in 63%) besides CD68-staining.
authors.affiliation: Institut für Pathologie, Register für Gliedmassentumoren, Berufsgenossenschaftliche Kliniken Bergmannsheil, Ruhr-Universität Bochum. Cornelius.Kuhnen@ruhr-uni-bochum.de
authors.forename: C
authors.initials: C
authors.lastname: Kuhnen
authors.forename: K-M
authors.initials: KM
authors.lastname: Müller
authors.forename: S
authors.initials: S
authors.lastname: Rabstein
authors.forename: A
authors.initials: A
authors.lastname: Kasprzynski
authors.forename: P
authors.initials: P
authors.lastname: Herter
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D005870:Giant Cell Tumors / Q000473:pathology* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D008938:Mitosis; D012983:Soft Tissue Neoplasms / Q000473:pathology*; D013583:Synovial Membrane / Q000473:pathology*; D013710:Tendons / Q000473:pathology*
chemical_list: D015703:Antigens, CD