Congenital Aneurysmal Bone Cyst in a Foal

Uneeda Bryant, Luke Fallon, Matilda Lee, Roy Pool

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


A 2-week-old female Thoroughbred foal was born with a firm, expansile, progressively enlarging mass involving the left hemimandible. Grossly, the mass was composed of variably sized cavernous spaces containing clotted blood and serofibrinous exudate, separated by fibrous and fibroosseous septa. Histologically, the spaces were lined by flattened to plump spindle cells and contained hemorrhage, fibrin, and multinucleated osteoclast-like cells. The septa separating adjacent cavernous spaces contained interlacing bundles and streams of spindle cells, multinucleated giant cells, hemosiderophages, mineral deposits, and spicules and trabeculae of reactive and poorly mineralized bone. A diagnosis of congenital aneurysmal bone cyst was made based on histologic features. The pathogenesis for the development of aneurysmal bone cysts is still undetermined, although spindle cells lining cavernous spaces in the foal exhibited negative immunolabeling for factor-VIII (F8) and positive immunolabeling for smooth muscle actin, suggesting vascular smooth muscle origin and possible blood flow disturbance.

Original languageEnglish
Pages (from-to)320-323
Number of pages4
JournalJournal of Equine Veterinary Science
Issue number6
StatePublished - Jun 2012


  • Aneurysmal bone cyst
  • Bone cyst
  • Congenital
  • Foal

ASJC Scopus subject areas

  • Equine


Dive into the research topics of 'Congenital Aneurysmal Bone Cyst in a Foal'. Together they form a unique fingerprint.

Cite this