title: Angiosarcoma at unusual sites. A report of two cases with aspiration cytology and diagnostic pitfalls.
abstract: BACKGROUND
  Angiosarcomas are uncommon soft tissue neoplasms with a predilection for skin and superficial soft tissues.
  
  
  METHODS
  Two cases of angiosarcoma occurred at unusual sites, the parotid gland and lung. The parotid lesion was characterized by malignant cells present singly, in loose groups, in tight three-dimensional aggregates and in acinar formation initially misinterpreted as an adenocarcinoma. The lung mass showed malignant cells in association with vascular endothelium, suggestive of angiosarcoma. Both cases were negative for Ulex europaeus and Factor VIII-related protein but demonstrated strong immunopositivity for CD31, a highly specific endothelial marker.
  
  
  CONCLUSIONS
  In the absence of vasoformative structures, important diagnostic pitfalls are pseudovascular adenoid squamous cell carcinoma, poorly differentiated adenocarcinoma, melanoma and lymphoma. Immunocytochemical studies and clinical history are essential to the correct diagnosis.
authors.affiliation: Department of Pathology, Baylor College of Medicine and Methodist Hospital, Houston, Texas 77030, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Mullick
authors.forename: D R
authors.initials: DR
authors.lastname: Mody
authors.forename: M R
authors.initials: MR
authors.lastname: Schwartz
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D003937:Diagnosis, Differential; D005260:Female; D006394:Hemangiosarcoma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D008297:Male; D010307:Parotid Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism
chemical_list: D019408:Platelet Endothelial Cell Adhesion Molecule-1