Primary orbital melanoma masquerading as vascular anomalies

PURPOSE: To review two cases of primary orbital melanoma presenting like orbital vascular anomalies. METHODS: Retrospective review of clinical presentation, treatment, radiology and pathology for two patients under the care of the Orbital Clinic at Moorfields Eye Hospital. RESULTS: Both lesions presented with the appearance and behaviour of vascular anomalies. In one case, a spindle cell melanoma appeared to be a low flow vascular anomaly with a loculated secondary haemorrhage and, in the other case, a melanoma of soft parts was considered to be an arteriovenous malformation and responded partially to embolisation. CONCLUSION: Primary malignant melanoma may present as a secondary vascular lesion of the orbit and this very rare tumour should be considered in the differential diagnosis of any vascular anomaly.