Figure 18-4 Retinal cavernous hemangioma. A, Note multiple tiny vascular saccules and associated white fibrovascular tissue. B, Note clumped vascular saccules (grape cluster configuration). C, When lesions are small, findings may be subtle.

(Part B courtesy of Timothy G. Murray, MD.)

Arteriovenous Malformation

Congenital retinal arteriovenous malformation (racemose hemangioma) is an anomalous artery-to- vein anastomosis ranging from a small, localized vascular communication near the optic disc or in the periphery to a prominent tangle of large, tortuous blood vessels throughout most of the fundus (Fig 18-5). Racemose refers to the clustered or bunched nature of the vessels. When associated with an arteriovenous malformation of the midbrain region, this condition is generally referred to as

Wyburn-Mason syndrome (see BCSC Section 5, Neuro-Ophthalmology, and Section 6, Pediatric Ophthalmology and Strabismus). Associated similar arteriovenous malformations may appear in the orbit and mandible.

Figure 18-5 Retinal arteriovenous malformation. A, Clinical appearance. B, Fluorescein angiogram showing absence of a capillary bed between the afferent and efferent arms of this retinal arteriovenous communication. Note the absence of fluorescein leakage, which is characteristic of this lesion.