Magnetic resonance imaging. Diverse appearances of uveal malignant melanomas
P. A. Bloom, J. D. Ferris, D. A. Laidlaw and P. R. Goddard
Department of Ophthalmology, Bristol Eye Hospital, England.
Fifteen patients with uveal malignant melanomas were studied by magnetic
resonance imaging. The magnetic resonance imaging appearances varied from
those that have been reported previously to be characteristic of these
tumors. In our series, malignant melanomas were of high signal on the T1
sequence and of variable but usually also of high signal on the T2 and
Short Tau Inversion Recovery (STIR) sequences, a signal combination rarely
described before. We postulate that magnetic resonance imaging appearances
may be dependent on variations in histologic factors and on the type and
field strength of the scanner used. It is widely believed that the
paramagnetic melanin in malignant melanomas gives these tumors
characteristic magnetic resonance imaging appearances, but our finding of
diverse magnetic resonance imaging appearances for proved malignant
melanomas suggests that this may not always be the case. We advise caution
in diagnosing malignant melanomas from magnetic resonance imaging
appearances alone.
