Abstract
Purpose: :
Vasculogenic mimicry patterns, formed by highly invasive tumor cells, connect to endothelial cell lined blood vessels and have been shown to contain fluid in vitro and in vivo. This study was designed to determine if fluid leaks into vasculogenic mimicry patterns without circulation or if fluid circulates in these patterns.
Methods: :
Indocyanine green laser scanning confocal angiography (Heidelberg HRA, Heidelberg Engineering) was performed on five patients with posterior choroidal melanoma. Blood was drawn from the contralateral arm of the ICG injection site before and 1 minute after the injection of ICG. The time to first filling of retinal vessels and vasculogenic mimicry patterns, and the time at which no fluorescence could be detected by the HRA instrument were recorded. After fluorescence was no longer detected in either of these two circulations, the patient’s pooled blood was imaged by the Heidelberg HRA.
Results: :
Looping vasculogenic mimicry patterns were detected focally in all 5 patients. Fluorescence in retinal vessels was noted 24.9 ± 6 seconds after injection, and was undetetable by the Heidelberg HRA within 10:04.5 ± 1:38 minutes post injection. Looping vasculogenic mimicry patterns were first detected 18.7 ± 5 seconds after injection and were detectable until 3:54 ± 0:55 minutes post injection. Blood drawn before ICG injection did not autofluoresce and the ICG–containing blood pooled in the tube continued to fluoresce for at least 1 month post injection.
Conclusions: :
Vasculogenic mimicry patterns are not part of the endothelial cell lined vascular system and fluid must enter these patterns through leakage. However, the rapid influsion of ICG into these patterns after injection and the disappearance of fluorescence dectable by the Heidelberg HRA suggest that fluid circulates in these patterns and does not accumulate as a stagnant pool.
Keywords: melanoma • oncology • imaging/image analysis: clinical