Orbital melanoma: Recurrence versus primary: A diagnostic dilemma

Primary orbital melanoma: A report of a case and comprehensive review of the literature

Purpose: To review the clinical features and treatment-associated outcomes of primary orbital melanoma among cases reported in the literature and to present a case treated with orbital exenteration and post-operative radiotherapy.Methods: Case reports and case series on primary orbital melanoma published in the literature between 1980 and 2020 were reviewed. Data collected included patient demographics, presenting ocular symptoms, diagnostic imaging, histology, management, and outcomes.Results: Eighty-eight cases of primary orbital melanoma were reviewed. The average age at presentation was 45 years and 58% of patients were male. The most common presenting symptoms and signs were proptosis (73%), decreased visual acuity (32%), pain (14%), diplopia (15%), and palpable mass (9%). Imaging frequently showed a well-circumscribed enhancing lesion. Diagnosis was made by histology in all cases, and orbital blue nevus was identified in 42%. In the majority of cases, treatment consisted of orbital exenteration (54%) or excision (38%). Adjuvant radiotherapy was given in 47% of cases. For the 72 patients with reported outcomes, 36% had metastases, 15% had local recurrence, and 32% died of metastatic disease. Patients who received surgery and radiotherapy had improved survival compared to those who received surgery alone (p = .01). There was no difference in survival between those who underwent orbital exenteration or excision (p = .16).Conclusions: Primary orbital melanoma is a rare malignancy and should be considered in patients with a history of unilateral proptosis and a well-defined orbital mass on imaging. Surgery remains the mainstay of treatment. Adjuvant radiotherapy may improve patient survival.

Primary Orbital Melanoma: Presentation, Treatment, and Long-term Outcomes for 13 Patients

BACKGROUND

Periocular melanoma is a rare but often deadly malignancy that arises in the uvea (commonest origin), conjunctiva or orbit (rarest primary site). Melanoma accounts for 5-10% of metastatic/secondary orbital malignancies, but only a tiny proportion of primary orbital neoplasia. Primary orbital melanoma (POM) is exceedingly rare, with approximately 50 cases reported to date.

METHODS

All patients seen in the orbital unit at a tertiary referral hospital (1991-2016) with a biopsy-proven diagnosis of POM were identified from a diagnostic database and were studied. The case notes, imaging, surgical approach, and histology were reviewed.

RESULTS

Thirteen patients (five male; 38%) presented with isolated malignant melanoma of the orbit, for which no other primary site was identified at presentation or during an average follow-up of 44 months (median 22; range 0-13 years). The patients presented between the ages of 40 and 84 years (mean 55.5; median 48 years) and typically gave a short history of rapidly increasing proptosis and eyelid swelling. On the basis of history, a malignant lesion was suspected in most patients and all underwent incisional biopsy, with debulking of the mass in 10 (77%) patients, and skin-sparing exenteration in 3/13 (23%). Ten patients underwent orbital radiotherapy and the survival to date ranged from 9 months to 14 years (mean 55 months; median 23 months); two patients received solely palliative care for widespread disease and one patient refused orbital radiotherapy. Five of the 13 (38%) patients died from the disease.

DISCUSSION

POM is a very rare malignancy, but clinical analysis of this cohort gives insight into disease presentation and prognosis. The tumor typically presents with a rapidly progressive, well-defined mass that is, in some cases, amenable to macroscopically intact excision. Unusual for malignant melanoma, some of these patients can show an unusually long period of quiescent disease after surgical debulking and radiotherapy.

Evisceration and ocular tumors: What are the consequences?

PURPOSE

Evisceration can be performed for blind, painful eyes. This surgery can promote the dissemination of tumor cells within the orbit if an ocular tumor has been missed preoperatively.

METHODS

We reviewed the medical records of patients who were eviscerated for blind, painful eyes between 2009 and 2014 and who were referred after the surgery to the Institut Curie or the Rothschild Foundation in Paris. We included the patients with a histological diagnosis of ocular tumor or orbital recurrence. Cytogenetic analysis was performed whenever possible.

RESULTS

Four patients turned out to have an ocular tumor after evisceration (two choroidal melanomas, a rhabdoid tumor and an adenocarcinoma of the retinal pigment epithelium); two had a history of prior ocular trauma. The tumors were diagnosed either on histological analysis of the intraocular contents (2 patients) or biopsy of orbital recurrence (2 patients). Prior to evisceration, fundus examination was not performed in 3 patients. One had preoperative imaging but no intraocular tumor was suspected. At the time of this study, 3 patients had had an orbital recurrence and died. We also found 2 patients who had an evisceration despite a past history of choroidal melanoma treated with proton beam therapy.

CONCLUSION

We showed that evisceration of eyes with unsuspected ocular malignancies was associated with a poor prognosis due to orbital recurrence and metastasis. The evisceration specimen should therefore always be sent for histological analysis in order to perform prompt adjuvant orbital radiotherapy if an ocular tumor is found.