Purpose: To estimate the proportion of 'false positives' in patients referred with a diagnosis of suspected choroidal melanoma by general ophthalmologists to an ocular oncology centre.
Methods: A prospective study of patients referred by general ophthalmologists to an ocular oncology centre was undertaken over a 14-week period. The diagnosis was made clinically in patients receiving radiotherapy or phototherapy and was confirmed by histopathology in patients requiring fine needle aspiration biopsy (FNAB) or enucleation.
Results: A total of 132 new patients were seen in 10 consecutive ocular oncology clinics between 29 March 2004 and 5 July 2004. The mean age was 62 years (range 28-88 years) and 60 (55%) were female. Among the 83 suspected malignant posterior segment lesions, the suspected diagnosis included choroidal melanoma (73), choroidal metastasis (6), 'choroidal tumour' (3), and 'Solid retinal detachment' (1). Only 50 of the 73 suspected melanomas were confirmed (68.5%; 95% CI, 57-78%), the oncologist's diagnosis in the remaining 23 being choroidal naevus (10), choroidal metastasis (1), circumscribed choroidal haemangioma (2) and others (10). Only one of six patients with suspected metastases had this condition, the remainder having melanoma (1), lymphoma (1), circumscribed choroidal haemangioma (1), and others (2). The 'choroidal tumours' and 'solid detachments' were found to be chorio-retinal disciform scar (1), varix of vortex vein (1), eccentric CNV (1), and subretinal haemorrhage (1)
Conclusion: Approximately 30% of patients referred to an ocular oncology service with the diagnosis of choroidal melanoma have an incorrect diagnosis.