Soft tissue
Benign vascular tumors
Symplastic hemangioma

Author: Vijay Shankar, M.D. (see Authors page)

Revised: 16 September 2016, last major update November 2012

Copyright: (c) 2003-2016,, Inc.

PubMed search: symplastic hemangioma

Cite this page: Symplastic hemangioma. website. Accessed October 26th, 2016.
Definition / General
  • Hemangioma with bizarre stromal cells in fibrinous material around vessels
  • Limited published reports
  • Due to degenerative atypia of vascular smooth muscle and interstitial cells, similar to symplastic leiomyoma of uterus or ancient schwannoma
Micro Description
  • Vascular lesion with thick walled and variably dilated vessels
  • Degenerative atypia of vascular smooth muscle and interstitial cells within a preexisting vascular lesion, with minimal endothelial cell atypia
  • Atypical cells are spindled or epithelioid with variable hyperchromasia, nuclear enlargement, pleomorphism and multinucleation (J Cutan Pathol 2006;33:735)
  • Perivascular hemorrhage, vascular thrombosis and focal papillary endothelial hyperplasia are common
  • Stroma has hemosiderin and mononuclear inflammation
  • May have fibrous tissue, stromal edema or fat cells within superficial dermis
  • May have rare atypical mitotic figures or bizarre lipoblast-like stromal cells
  • No endothelial cell multilayering
  • No mitotic figures
Micro Images

Lower extremity

Positive Stains
Differential Diagnosis
  • Angiosarcoma: endothelial cells are atypical, there is frequent multilayering of cells and prominent mitotic activity
  • Pleomorphic hyalinizing angiectatic tumor: infiltrative lesion of superficial soft tissue of distal extremities; shows heavily hyalinized, fibrin containing vessels, spindled and pleomorphic stromal cells with frequent intranuclear inclusions