1. Two cases are reported in which there was diffuse fibro-fatty overgrowth or tumour formation involving the adipose tissue of the median nerve. In each the diagnosis was confirmed by operation and histological examination.

2. The first case is an example of the developmental abnormality usually referred to as "macrodystrophia lipomatosa." The second case should be termed fibrolipoma.

3. The literature is reviewed; no case of fibrolipoma has been recorded.