title: CD10 is expressed in most epithelioid hemangioendotheliomas: a potential diagnostic pitfall.
abstract: BACKGROUND
  -Epithelioid hemangioendothelioma (EHE) is a vascular neoplasm that occasionally is difficult to distinguish from primary/metastatic carcinomas, particularly when EHEs express keratins. We recently encountered an EHE with strong CD10 positivity mimicking renal cell carcinoma.
  
  
  OBJECTIVE
  -To examine sensitivity and specificity of CD10 in EHE.
  
  
  METHODS
  -Nine EHEs were stained with keratins, factor VIII, CD31, CD34, and CD10. Mimics of EHE were also retrieved and stained with CD10.
  
  
  RESULTS
  -The EHE patients included 5 men and 4 women. Patients ranged in age from 24 to 74 years. Tumors were located in liver (3), skin (2), lung/pleura (2), and sternomastoid and mediastinum (1 each). Two had skin metastases. All EHEs were positive for vascular markers. A total of 7 of 9 primary tumors expressed cytoplasmic and intracytoplasmic luminal CD10. The 2 skin metastases were positive, whereas 2 primary skin EHEs were negative. Of the mimics, CD10 showed staining in 7 of 23 cases: 3 of 3 renal cell carcinomas, 1 of 7 other carcinomas, 2 of 3 epithelioid angiosarcomas, 1 of 3 melanomas, 0 of 3 mesotheliomas, and 0 of 4 epithelioid hemangiomas.
  
  
  CONCLUSIONS
  -CD10 has a sensitivity of 78% (confidence interval, 63.6%-92.4%) and specificity of 70% (confidence interval, 54%-85.9%) for EHE. There is a growing list of tumors that show expression of CD10. Pathologists should be aware of this diagnostic pitfall.
authors: Department of Pathology, University Health Network, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada. weinrebi@yahoo.ca
authors: Ilan
authors: I
authors: Weinreb
authors: Kristopher S
authors: KS
authors: Cunningham
authors: Bayardo
authors: B
authors: Perez-Ordoñez
authors: David M
authors: DM
authors: Hwang
mesh_terms: D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D002292:Carcinoma, Renal Cell / Q000175:diagnosis / Q000378:metabolism; D003937:Diagnosis, Differential; D015622:Epithelioid Cells / Q000737:chemistry / Q000473:pathology; D005260:Female; D018323:Hemangioendothelioma, Epithelioid / Q000175:diagnosis* / Q000378:metabolism*; D006394:Hemangiosarcoma / Q000175:diagnosis / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000175:diagnosis / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015260:Neprilysin / Q000096:biosynthesis*; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D015260:Neprilysin