The neural crest origin of uveal melanomas.

On the basis of two cases the relation between 'neurogenic' tumours (neurinomas, neurilemmomas, Schwannomas, neurofibromas) and malignant melanomas of the uvea is discussed with emphasis on the close association of both groups of neoplasms with the ciliary nerves. The great histopathological diversity between different cases of melanoma as well as within individual cases is also pointed out. On histological and cytological criteria it may be difficult to differentiate between the 'neurogenic' tumours and the highly differentiated, spindle cell variants of the melanomas. Since all these tumours are derived from the neural crest, they might be grouped under one common heading. It is postulated that 'neurogenic' tumours have been overdiagnosed to the disadvantage of the highly differentiated spindle cell melanomas.