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

Abstract

BackgroundPeriocular 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.MethodsAll 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.ResultsThirteen 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.DiscussionPOM 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.

Detection of mutations in SF3B1, EIF1AX and GNAQ in primary orbital melanoma by candidate gene analysis

“…POM is an extremely rare tumour, with approximately 60 cases reported to-date in the literature. One striking feature is the highly variable prognosis – whilst most reported cases have a dismal prognosis, a subset of patients appear to follow a relatively benign course [6, 7]. This feature was certainly observed in the patient cohort used in this study – some patients had aggressive primary disease with widespread systemic involvement and rapid deterioration; whereas other patients survived for more than a decade [7].…”

“…Informed, written consent was obtained from patients and research adhered to the tenets of the Declaration of Helsinki. Twelve tumour DNA samples from 11 patients were included in the study; the demographics and clinical course (including disease presentation, occurrence of metastasis and overall survival) of the patients has been previously published but is also summarised in Table 1 [7]. Prognosis was defined as poor (survival of < 6 months with or without metastasis), intermediate (survival > 6 months with local or systemic spread of disease) or good (survival > 6 months without spread; or very late recurrence of disease (> 10 years)).…”

“…The prognosis of POM appears to be quite variable. Generally, the disease is considered to have a very poor prognosis, but there appears to be a subset of patients who have long-survival [6, 7].…”

Malignant melanoma of the rectum presenting as orbital metastasis

“…They may also occur de novo, but usually in association with pigmentary changes within periocular tissues; like nevus of Ota, blue cellular nevus, or oculodermal melanosis. [ 9 ] Secondary orbital melanoma can be seen in cases of extrascleral extension of an intraocular melanoma; as orbital extension of conjunctival and eyelid melanoma; as local recurrence after surgical treatment of ocular melanomas; and finally as orbital metastases from a distant cutaneous melanoma. [ 7 ] Metastases from nonocular and noncutaneous locations are very uncommon with very few reported cases.…”

Primary Orbital Melanoma: An Investigation of a Rare Malignancy Using the National Cancer Database

“…However, the choice of orbital exenteration for POM is grounded in observation from uveal melanoma and survival benefits between possible treatment sequences has only recently been explored. 2,[19][20][21][22] Similarly, survival after diagnosis has been highly variable, with one estimate of 62% survival 4.5 years after diagnosis and other small cohort studies suggesting mean survival of 6 years. 2,13 So far, the knowledge of these epidemiologic trends and the oncologic outcomes of POM are limited to case reports, case series, and institutional reviews, with no multicenter studies to validate the findings and further evaluate the best management options for patients.…”