Soft tissue lesions

Topic Completed: 1 December 2012

Minor changes: 4 February 2020

Copyright: 2003-2019,, Inc.

PubMed Search: Hemangioendothelioma mediastinum

Hanni Gulwani, M.B.B.S.
Page views in 2019: 337
Page views in 2020 to date: 208
Table of Contents
Epithelioid | Kaposiform
Cite this page: Gulwani H. Hemangioendothelioma. website. Accessed May 29th, 2020.
Poor prognostic factors
Case reports
Gross description
  • Circumscribed but unencapsulated mass, associated with adventitia of large blood vessels
  • Has glistening and hemorrhagic cut surface

Microscopic (histologic) description
  • Cords or disorganized sheets of markedly vacuolated polygonal cells in myxohyaline stroma
  • Variable nuclear atypia
  • Variable mitotic activity

Microscopic (histologic) images

Images hosted on other servers:

Various stains

Histologic sections of a tumor

Positive stains
Negative stains
Electron microscopy description
  • Weibel-Palade bodies

Differential diagnosis
Definition / general
  • Rare pediatric neoplasm

  • Usually in soft tissue of retroperitoneum and extremities

Clinical features
  • May be locally invasive but distant metastases are rare
  • Associated with Kasabach-Merritt syndrome, a consumptive coagulopathy associated with vascular lesions
  • Not associated with Kaposi sarcoma or human herpesvirus 8

Case reports
  • Aggressive chemotherapy may be helpful

Microscopic (histologic) description
  • Diffusely infiltrative, vascular, spindled tumor infiltrating lobules of thymus, which may be depleted of lymphocytes
  • Resembles capillary hemangioma and Kaposi sarcoma
  • May have glomeruloid proliferations of epithelioid endothelial cells
  • Cells may have intracytoplasmic lumina with hyaline globules, hemosiderin deposition
  • Spindled cells have slitlike vascular spaces resembling Kaposi sarcoma
  • Frequent mitotic activity

Microscopic (histologic) images

Images hosted on other servers:

Spindled cells surround residual thymic structures

Glomeruloid nests with intracytoplasmic lumina

Tumor cells are keratin-, residual thymus is keratin+

Positive stains
Negative stains
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