title: [A clinicopathologic study on 9 cases of epithelioid hemangioendothelioma].
abstract: OBJECTIVE
  To study the clinicopathological features of epithelioid (histiocytoid) hemangioendothelioma (EHE).
  
  
  METHODS
  9 cases of EHE were examined by light microscopy and immunohistochemistry, 1 case with ultrastructural observation.
  
  
  RESULTS
  The patients' age ranged from 16 to 47 years (mean 32 years). The lesions occurred in both sexes and presented at a variety of sites including head and facial area (4 cases), upper limbs (3 cases) and lower limbs (2 cases). The morphological characters were: (1) "epithelioid" or "histiocytoid" tumor cells; (2) rounded or polygonal tumor cells arranged in nests, cords and irregular patterns; (3) the tumor cells were embedded in myxoid or hyaline matrix; (4) primitive lumen formation within a single tumor cell (intracytoplasmic lumens); (5) lack of pleomorphism, mitotic activity and necrosis; (6) presence of spindle cell hemangioendothelioma in some cases; (7) osteoclast like giant cells scattered throughout the entire lesion were observed in one case. Immunohistochemistry studies on 7 cases found that tumor cells were positive for vimentin (7/7), factor VIII-RAg (5/7), CD31 (5/7), CD34 (5/7), cytokeratin (2/7), CD68 and alpha-AT (1/7). Ultrastructural study of 1 case demonstrated Weibel-Palade bodies and an abundance of intermediate filaments in the cytoplasm. The follow-up of 6 cases found that 3 cases developed local recurrences but none of them metastasized.
  
  
  CONCLUSIONS
  EHE is a distinctive low-grade sarcoma whose etiology remains unknown. Recognizing its morphological characters is important to avoid confusion with other similar lesions.
authors.affiliation: Department of Pathology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, China.
authors.forename: R
authors.initials: R
authors.lastname: Lai
authors.forename: Y
authors.initials: Y
authors.lastname: Tian
authors.forename: X
authors.initials: X
authors.lastname: Feng
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: W
authors.initials: W
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000737:chemistry / Q000473:pathology*; D018323:Hemangioendothelioma, Epithelioid / Q000737:chemistry / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D014746:Vimentin / Q000032:analysis; D014841:von Willebrand Factor / Q000032:analysis
chemical_list: D019408:Platelet Endothelial Cell Adhesion Molecule-1; D014746:Vimentin; D014841:von Willebrand Factor