Eye-Sparing Treatment of Massive Extrascleral Extension of Choroidal Melanoma

Uveal melanoma is the most common primary intraocular malignant neoplasm, and its management is still controversial. Enucleation was for many years considered the preferred method of treatment, but radiation therapy and other conservative treatments have been used with increasing frequency during the last 2 decades. These conservative methods of management have not been used often in cases of extrascleral extension of uveal melanomas. We report a case of massive orbital extension of a choroidal melanoma managed by resection of the extrascleral portion of the tumor and proton beam irradiation (PBI) of the intraocular portion of the tumor.

A 68-year-old white man was referred for evaluation of a left orbital mass. The lesion was first noticed as a superotemporal forniceal mass. Its presence was confirmed by magnetic resonance imaging (Figure 1).

Best-corrected visual acuity was 20/25 OD and 20/30 OS. External examination revealed 2 mm of proptosis on the left side. Adnexal palpation demonstrated a firm, mobile, superotemporal orbital mass on the left side that did not appear to be fixed to the orbital rim. Anteriorly, the mass appeared as an elevated and heavily pigmented subconjunctival lesion (Figure 2). A transconjunctival incisional biopsy of the mass was performed. Histopathological examination of the biopsy specimen revealed epithelioid melanoma (Figure 3). The cells stained positively for S100 and HMB45 antigens.

The patient was referred to the retina service for evaluation and possible treatment. Dilated funduscopic examination demonstrated an elevated and moderately pigmented choroidal mass temporal to the left macula. This lesion measured approximately 12×9 mm in diameter and 1.6 mm in height by ultrasonographic examination, which also demonstrated the orbital portion of the tumor (Figure 4). The diagnosis of primary choroidal melanoma with massive extrascleral extension was made. An extensive workup was negative for metastases.

The different management alternatives were discussed, including exenteration, modified enucleation, and resection of the extrascleral portion of the tumor with subsequent PBI of the intraocular tumor. The patient preferred the last of these choices. A transconjunctival orbitotomy was performed to expose the orbital portion of the tumor. The encapsulated orbital portion of the dark, firm tumor mass was completely excised. The orbital mass was contiguous with a thin stalk of tumor projecting through the sclera. Histopathological examination confirmed the diagnosis of epithelioid melanoma. Transillumination of the globe confirmed that the nidus of the remaining intrascleral tumor was centrally located within the shadow of the fundus lesion. Four tantalum clips were sutured on the sclera to outline the margins of the choroidal tumor. The patient was then treated with PBI for the choroidal and remaining intrascleral portion of the tumor. Two weeks after the completion of PBI, the patient received interferon, according to our adjuvant experimental protocol for patients with uveal melanoma at high risk of developing metastases.

Eight weeks after the completion of PBI, the best-corrected visual acuity was 20/25 OS. No postoperative diplopia was noted, and the exophthalmos completely resolved. The fundus lesion appeared unchanged.

Extrascleral extension of intraocular uveal melanoma is uncommon, occurring in between 2.5% and 21% of cases.^1-6 Along with other risk factors, such as increased tumor diameter, epithelioid cell type, ciliary body involvement, and advanced patient age, extrascleral extension has a negative effect on patient survival.^2-5 More than 3 decades ago, Starr and Zimmerman¹ noted that patients with extrascleral extension of their uveal melanomas were twice as likely to die of metastatic disease 5 years after enucleation than those patients who lacked extrascleral extension.

Formerly observed at the time of enucleation or during gross or histopathological examination of enucleated globes, extrascleral extension is now often detected prior to the initiation of therapy, through the use of computed tomography, magnetic resonance imaging, and opththalmic ultrasonography. In our patient, magnetic resonance imaging demonstrated the presence of a large orbital mass and ultrasonography clearly showed the intraocular and massive orbital portions of the tumor adjacent to one another. The anatomical relationship was confirmed at the time of surgery, when the extraocular mass was observed to emanate from a small tract of scleral tumor exiting the globe.

Proponents of enucleation and even exenteration in cases of posterior uveal melanoma with extrascleral extension believe that these aggressive treatments should decrease the metastatic rate and increase patient survival.² However, other investigators have failed to reveal any long-term improvement in survival in patients treated with exenteration.^3,4,7 Some investigators consider the role of exenteration in these cases as mainly palliative.^1,6 Rendahl⁸ proposed that exenteration in cases of uveal melanoma with extrascleral extension might widely disseminate tumor cells. In 1991, Shields and Shields⁶ reported a series of 10 patients with massive orbital extension of their posterior uveal melanomas. Seven of these patients had orbital tumors when initally seen and the remaining 3 had orbital tumor recurrences after enucleation. Six of the patients with orbital involvement at first visit and 2 of the patients with orbital recurrence after enucleation underwent eyelid-sparing exenterations.

There is not adequate data to determine whether exenteration is beneficial, neutral, or detrimental to the mortality rate in patients with extrascleral extension of posterior uveal melanoma. With the information available, conservative management with resection of the orbital portion of the tumor and subsequent PBI seemed justified in our patient. After 6 months of follow-up, his visual function has remained excellent and the symptoms related to his prior orbital mass have resolved. Long-term follow-up of this patient is planned.

This study was supported by the Uveal Melanoma Fund, Massachusetts Eye and Ear Infirmary, Boston.

Reprints: Evangelos S. Gragoudas, MD, Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02114-3096.