ECHOGRAM IN MELANOMA OF THE CHOROID*

DiAGNOSIS is often difficult in melanoma of the choroid. This is evidenced e.g. by frequent misdiagnosings which come to light only after the enucleation of the bulbus (Reese, 1957) and by numerous more or less reliable methods of examination which have been applied for the determination of this tumour. Among the latest and, judging by the initial results, the most reliable methods of examination is the diagnostic use of the echogram. Mundt and Hughes (1956) and Oksala and Lehtinen (1957) were the first to use ultrasound in the diagnosis of intrabulbar tumours. These investigators found that, even in those cases in which ophthalmoscopic exploration of the tumour was prevented by detachment of the retina or opacity of the intermediary substances of the eye, it was possible to diagnose the intrabulbar tumour with a high degree of certainty by means of echoes registered by an ultrasonic apparatus. Oksala and Lehtinen came to the conclusion that the echoes reflected from a choroidal melanoma could be positively observed on the screen of the Braun tube even at the stage when the height of the tumour was only about 2-3 mm. On the basis of these observations the echogram traced by a melanoma of the choroid was marked by the typical feature that the tumour tissue produced on the screen an irregular accumulation of echoes, the echogram varying somewhat according to the direction of investigation. The line traced by the echo and visualized on the screen did not return to the zero-line after having encountered the tumour. This finding was based on the echogram obtained from one patient with melanoma of the choroid. In this case the tumour was fairly small, its height being 4-5 mm. If the intrabulbar tumour is larger, we shall of course obtain on the screen a longer echogram which is more easily examined. In the first patient now reported by me the choroidal melanoma could not be diagnosed before the tumour had grown to a height of 10 mm. A disease of this kind provided a first-rate opportunity of studying the echogram given off by melanoma of the choroid. Since the literature dealing with this new method of research is very scanty, and since it is by no means always easy to interpret echograms produced by various diseases of the eye, a report of two cases together with the results of investigation appears justified.