Detection of extrascleral extension in uveal melanoma with histopathological correlation

Uveal melanoma is the most common primary intraocular malignancy. Extrascleral extension (ESE) is rare, but associated with an increased rate of orbital recurrence and an overall poor prognosis. Clinical studies show low rates when compared with histological studies. Due to the prognostic importance of ESE, we sought to compare our clinical, intraoperative, and histological detection rates.

A retrospective cross-sectional case series.

A list of eyes enucleated for uveal melanoma was compiled from the admissions records of the London Ocular Oncology Service during the 28-month period, i.e. January 2010-April 2012. The surgical and clinical notes of patients with histopathology proven ESE were reviewed to determine when it was first diagnosed or suspected. The subsequent management of these cases is discussed.

A total of 16 out of 174 (9%) eyes had histologically proven ESE. Eight of 16 cases were detected preoperatively at clinical examination, including the use of ocular ultrasound, 3 of 16 were discovered intra-operatively, and 5 of 16 deemed microscopic ESE, were first detected on histological examination. Seven of 7 (100%) of cases with anterior ESE were detected clinically by slit lamp biomicroscopy, while only 1 out of 9 (11%) of cases with posterior ESE was detected preoperatively with ultrasound.

Slit lamp biomicroscopy is sensitive for detecting anterior ESE. Most posterior ESE is microscopic, but macroscopic posterior ESE may also be missed by B-scan ocular ultrasound. Orbital surgeons should be suspicious of clinically undetected posterior ESE, and consider adjuvant orbital radiotherapy in cases with macroscopic ESE.