A 65-year-old woman presented with multifocal, extrasceral spread of choroidal melanoma in the right eye 17 months after proton beam therapy. Multiple pigmented, subconjunctival lesions of the nasal globe are noted.
A, Primary posterior necrotic tumor with overlying tantalum marker suture (hematoxylin-eosin, original magnification ×10). Inset, Melanoma cells seen around the suture material (hematoxylin-eosin, original magnification ×40). B, Posterior extrascleral extension of the tumor (hematoxylin-eosin, original magnification ×2). Inset, Melanoma cells along the suture material (hematoxylin-eosin, original magnification ×20).
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Desai SJ, Kim HJ, Kersten RC, Bloomer MM, Vagefi MR. Extrascleral Spread of Choroidal Melanoma via Tantalum Marker Suture Track. JAMA Ophthalmol. 2013;131(12):1643–1645. doi:10.1001/jamaophthalmol.2013.5042
Proton beam irradiation allows globe-sparing treatment of uveal melanoma with excellent local control rates.1 Recurrence after radiotherapy is low, ranging from 2% to 5%. Treatment first requires delineation of the tumor by placement of tantalum markers that are sutured to the sclera.2 We report a case of multifocal, extrascleral spread of choroidal melanoma along the suture track of a tantalum marker after proton beam therapy.
A 65-year-old woman presented 17 months after proton beam irradiation for choroidal melanoma of the right eye with multiple, pigmented, subconjunctival lesions highly suspicious for recurrence with extrascleral extension. Review of outside records revealed that the original mass extended from the fovea supratemporally with a collar button configuration, measuring 16 × 14 mm at the base and 9 mm in height on B-scan ultrasonography. The patient underwent tantalum marker placement followed by proton beam therapy 3 weeks later. A total dose of 56 Gy (to convert to rad, multiply by 100) was given in 4 fractions. Thereafter, the patient was lost to follow-up.
Visual acuity on presentation to our institution was no light perception OD. Darkly pigmented subconjunctival nodules were apparent (Figure 1). A secluded pupil and vitreous hemorrhage precluded a fundus examination. B-scan ultrasonography demonstrated remnants of the primary tumor and an additional mass posterior to the globe that was confirmed with orbital magnetic resonance imaging. Findings on liver function tests, magnetic resonance imaging of the head and neck, positron emission tomography, and chest radiography were within normal limits. Given highly probable extraocular extension with multifocality, the tumor board recommended exenteration.
Gross pathology showed a large, posterior, pigmented choroidal mass with multiple extrascleral satellite lesions on the anterior aspect of the globe and one near the posterior aspect. Histopathology of the choroidal tumor demonstrated a necrotic central core with a peripheral edge of viable melanoma cells. The extrascleral sites of melanoma were not contiguous to the primary choroidal mass. Direct extension through episcleral channels was not observed. Instead, melanoma cells were seen neighboring and within suture material adjacent to the primary tumor site and at the site of posterior extrascleral extension (Figure 2).
Nearly half of recurrences of uveal melanoma are at the margin of the initial mass, probably as a result of treatment planning errors.1 Furthermore, larger melanomas are more likely to recur because of poorer radiosensitivity.2 Extraocular tumor spread is typically through anatomical conduits including aqueous channels, ciliary arteries, vortex veins, ciliary nerves, and the optic nerve.3 To our knowledge, this is the first report of extrascleral extension of melanoma along a suture track created from tantalum marker placement. There are no reports of scleral perforation during tantalum marker or plaque placement. However, it is known that scleral perforation can occur during strabismus (0.8% to 1.8%) and scleral buckle surgery (2.5%).4,5 Presumably, a needle pass penetrated the tumor to provide an avenue for tumor cells to spread beyond the highly localized treatment area of the proton beam. This case demonstrates the vigilance that must be taken in tantalum marker placement, tumor delineation, and timely delivery of an adequate dose of radiotherapy.
Corresponding Author: M. Reza Vagefi, MD, Department of Ophthalmology, University of California, San Francisco, 10 Koret Way, San Francisco, CA 94143 (firstname.lastname@example.org).
Published Online: October 3, 2013. doi:10.1001/jamaophthalmol.2013.5042.
Author Contributions: Desai had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Desai, Kersten, Vagefi.
Acquisition of data: Desai.
Analysis and interpretation of data: Desai, Kim, Bloomer.
Drafting of the manuscript: Desai, Vagefi.
Critical revision of the manuscript for important intellectual content: All authors.
Administrative, technical, or material support: Desai, Bloomer, Vagefi.
Study supervision: Kim, Kersten, Vagefi.
Conflict of Interest Disclosures: None reported.