Abstract
A 74-year-old man with an occult carcinoma of the colon developed pigmentation of the mouth and penis typical of the Peutz-Jeghers syndrome as the first manifestation of bilateral diffuse uveal melanocytic proliferation. The simultaneous appearance of extraocular pigmented lesion and those in the uveal tract of both eyes of this patient provides further evidence that bilateral diffuse uveal melanocytic proliferation may be caused by activation of occult melanocytic naevus cells in response to either a hormone-producing carcinoma or to some other common oncogenic stimulus.