Orbital Cavernous Hemangioma

Orbital cavernous hemangiomas are type 3 low-flow arteriovenous malformations. They typically affect women in their 40s, who most commonly present with painless proptosis. Orbital cavernous hemangiomas may be intra- or extra-conal. They should be differentiated from orbital capillary hemangiomas, which are hamartomatous proliferations of vascular endothelial cells and occur in infancy.

On CT, orbital cavernous hemangiomas are homogeneous lesions with variable attenuation depending on the presence of microcalcifications (coarse macrocalcifications are not typical). Larger lesions can cause remodeling of adjacent bone. Avid enhancement is typical. On MRI, the lesions are homogeneous and isointense to muscle. A hypointense pseudocapsule may also be seen. T2-weighted images reveal a hyperintense lesions with or without internal septations. On dynamic MRI, the lesions demonstrate small areas of enhancement initially with progressive enhancement on later phases.

Conventional angiography reveals contrast puddles extending into the late venous phase. Due to their low-flow characteristics, the lesions are not visible on routine MRA sequences.

References

Xian J, Zhang Z, Wang Z, Li J, Yang B, Chen Q, Chang Q, He L. Evaluation of MR imaging findings differentiating cavernous haemangiomas from schwannomas in the orbit. Eur Radiol. 2010 Sep;20(9):2221-8.