title: Angiomyofibroma of the orbit:  a hybrid of vascular leiomyoma and cavernous hemangioma.
abstract: OBJECTIVE
  The aim of this study was to describe a novel primary orbital vascular tumor combining elements of a vascular leiomyoma (angioleiomyoma) and a cavernous hemangioma.
  
  
  METHODS
  A critical review of clinical records, diagnostic tests, and radiographic studies combined with histopathologic evaluation with standard and special histochemical staining and immunohistochemical investigations was conducted.
  
  
  RESULTS
  A 44-year-old man slowly developed 5 mm of well-tolerated relative right proptosis with minimal motility disturbance and no visual decline. Computed tomography and magnetic resonance imaging demonstrated a medial and intraconal rounded mass that perfused slowly and whose anterior surface was well circumscribed. At surgery, the tumor was solid and pink with intersecting white bands and densely attached to surrounding normal tissues. The most adherent apical portion of the mass was left behind after subtotal excision. Histopathologically, only a partial pseudocapsule was discovered. The tumor was composed of cavernous channels, capillary zones, compressed lumens with linear strands of endothelium, and collections of muscular veins devoid of an elastica. Striking smooth muscle actin positivity was identified in disorganized masses of smooth muscle cells in the intervascular spaces and around the cavernous vascular units; these myocytes were intermixed with bundles of interstitial keloidal collagen. The endothelium was CD31 and CD34 positive for vascular endothelium and D2-40 negative for lymphatic endothelium.
  
  
  CONCLUSIONS
  The authors have classified this hybrid tumor an angiomyofibroma with low neoplastic potential and features of a malformation. It is a composite variant of cavernous hemangioma associated with a conspicuous proliferation of anomalous disorganized smooth muscle cells (leiomyoma). Most of the lesion lacked a pseudocapsule, which impeded surgical delivery. Incomplete excision is recommended in such cases as preferable to the complications that could ensue from overly aggressive efforts at complete removal, particularly at the orbital apex. Supporting this position is the observation that incompletely excised cavernous hemangioma generally does not recur.
authors.affiliation: David G. Cogan Laboratory of Ophthalmic Pathology, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts 02114, USA. Fred_Jakobiec@meei.harvard.edu
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Jakobiec
authors.forename: Fouad R
authors.initials: FR
authors.lastname: Zakka
authors.forename: Thanos D
authors.initials: TD
authors.lastname: Papakostas
authors.forename: Aaron
authors.initials: A
authors.lastname: Fay
mesh_terms: D000199:Actins / Q000378:metabolism; D000328:Adult; D018229:Angiomyoma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D018952:Antigens, CD34 / Q000378:metabolism; D014408:Biomarkers, Tumor; D006392:Hemangioma, Cavernous / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D009918:Orbital Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D014057:Tomography, X-Ray Computed; D014746:Vimentin / Q000378:metabolism
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D014746:Vimentin