Identification of extraocular extension in uveal melanoma by ophthalmological ultrasound

Uveal melanoma is the most common primary malignant intraocular tumour in the adult population, with a survival rate of 50% despite advances in treatment and knowledge of this disease. The presence of extraocular extension (EE) worsens the prognosis of these patients, so its proper identification can ensure its management and early intervention. Ophthalmological ultrasound is the technique of choice for the diagnosis and follow-up of these patients, both of the anterior EE using ultrasonic biomicroscopy (UBM), and the posterior EE using A and B ultrasound. The aim of this study is to describe the ultrasound characteristics of the BMU and the A and B ultrasound.

A descriptive and retrospective study is carried out on patients diagnosed with uveal melanoma (UM) and EE from 2003 to 2019. The ultrasound characteristics of the local disease and the follow-up after treatment were recorded completely and at each visit. In the case of anterior EE, photographs of the anterior segment and UBM were taken, while those involving the posterior segment were explored under A and B mode ultrasound. All enucleated eyes were sent for anatomopathological study.

Ten patients with an average age of 72.3 years were included. The largest proportion of them were medium-sized tumours, followed by large and small ones. The most frequent morphology of the primary tumour was cupuliform. All the EE presented lower internal reflectivity compared to the primary tumour. No trans-scleral connection bridges were found between the primary tumour and the EE in the ultrasound studies. 50% of patients underwent primary enucleation at the time of diagnosis of intraocular MU due to the presence of the EE, and the remaining 50% presented the EE after initial treatment of the primary tumour with I125 brachytherapy. Sixty percent of the patients presented with posterior EE, and were therefore diagnosed with ultrasound A and B. The most frequent histopathological pattern with 87.5% of patients was the epithelioid pattern.

Ultrasound scanning in patients with MU is mandatory for diagnosis and follow-up of EE. BMU and A and B ultrasound are the test of choice for anterior and posterior EE, respectively. EE have particular ultrasound characteristics such as low internal reflectivity, regularity of their contour and their location usually adjacent to the base of the primary intraocular tumor.