Ultrasonografia în melanomul coroidal necrotic

Uveal melanoma (UM) is the most common primary in­tra­ocu­lar malignancy in adults, originating in the uveal tract of the ocular globe. Spontaneous necrosis of choroidal melanomas is very rare, but some UMs may be predisposed to spontaneous necrosis due to ra­pid growth. The diagnosis of an extensively necrotic uveal melanoma can be challenging, because the as­so­cia­ted intraocular hemorrhage makes impossible the di­rect tumor visua­li­za­tion during ophthalmoscopy. Ul­tra­so­no­gra­phy is an imagistic tool based on sending and receiving sound waves (frequency above 20,000 Hz) with a probe which contains a piezoelectric transducer and works like a transmitter and receiver of sound waves in the same time. Ocular ultrasonography is the most commonly used imaging technique for determining the presence of a uveal melanoma, especially in opaque ocular media when dilated fundus examination of the eye cannot be made. In ophthalmology, we use two types of sound waves: an A-mode scan which uses frequencies of 8 MHz, and a B-mode scan for the visualization of intraocular struc­tures which uses frequencies of 10 MHz. Ocular ultra­so­no­gra­phy has many advantages in clinical practice, due to availability, no exposure to radiation and to low price. This article presents the difficulties associated with the diagnosis of necrotic uveal melanoma in the absence of fundus eye examination due to ocular opaque media. In this case, we should do the differential diagnosis with other pathologies that could resemble echographically uveal melanoma. In cases when ultrasonography can­not establish a clear diagnosis, we should use ancillary test.