Anastomosing hemangioma

Last revised by Joachim Feger on 19 Nov 2022

Anastomosing hemangiomas are benign vascular neoplasms consisting of thin-walled anastomosing vessels. These lesions have been just recently added to the WHO classification of soft tissue tumors in 2020 as a separate entity 1-3

Anastomosing hemangiomas are rare lesions with a wide range of distribution, usually but not exclusively seen in adults with some cases also reported in children 1,4.

The diagnosis of anastomosing hemangiomas is a histological one 1.

Diagnostic criteria according to the WHO classification of tumors: soft tissue and bone (5th edition) 1:

  • anastomosing vascular channels with a hobnail endothelial cell lining

The following histological criterion is desirable:

Many cases are found incidentally in imaging studies or on endoscopy due to visceral location. Superficial neoplasms might present as palpable nodules or masses with or without associated pain 1. Renal lesions might present with hematuria.

Pathologically anastomosing hemangiomas are poorly marginated lesions consisting of thin-walled interconnecting capillary-sized vessels with monolayered endothelial cells featuring a hobnail appearance 1-5.

The etiology of anastomosing hemangiomas is currently unknown 1.

Anastomosing hemangiomas are most commonly seen in the kidneys and retroperitoneum 1-5 but are generally found in multiple locations including the male and female genital tract, gastrointestinal tract, the liver the soft tissues and the skin 1,5.

Macroscopically anastomosing hemangiomas are well-delineated non-encapsulated lesions with a spongy hemorrhagic mahogany-like appearance 1,5. Tumor size is variable with examples up to 8 cm 4.

Microscopically anastomosing hemangiomas are characterized by the following histologic features 1-5:

  • loosely lobulated structure
  • anastomosing capillary-sized vascular channels
  • scattered single-layered endothelial cells with hobnail morphology and no multilayering
  • absent or rare mitotic activity
  • no or at best mild cellular atypia
  • common vascular thrombi
  • extramedullary hematopoiesis in a fair number of cases

Immunohistochemistry stains show positivity of CD34, CD31 and ERG 1,4,5.

Tumors are associated with GNAQ or GNA14 mutations in a majority of cases 1,4.

On imaging, anastomosing hemangiomas are usually well-marginated, but otherwise, non-specific imaging features 1,4,6. Multifocal lesions have been documented.

On ultrasound, lesions have been characterized as hypoechoic with plenty of flow signals on color Doppler 7.

On CT lesions have been characterized as hyperdense or hypodense with avid enhancement but heterogeneous attenuation 1,4,7 also due to fatty components 6.

On MRI anastomosing hemangiomas have been described as well-defined lesions with cystic and solid components 4,7-9. Enhancement patterns have been described as variable, mimicking more aggressive lesions 4,10.

  • T1: hypointense
  • T2: iso to hyperintense
  • T1 C+ (Gd): progressive centripetal enhancement

On FDG-PET minor tracer uptake has been observed 9

The radiological report should include a description of the following:

  • form, location and size
  • tumor margins
  • relation to organs and viscera
  • relation to muscular fasciae and skeletal muscles in soft tissues
  • relationship to local nerves and vessels

Anastomosing hemangiomas are benign lesions even in the setting of multicentricity or infiltrative growth 1. However, due to non-specific imaging features that overlap with several malignant tumors, they are often overtreated 4

Anastomosing hemangiomas have been first described by the American pathologists Elizabeth Montgomery and Jonathan I Epstein in 2009 2,4,5.

Conditions that can mimic the presentation and/or the appearance of anastomosing hemangiomas include the following:

ADVERTISEMENT: Supporters see fewer/no ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.