A precancerous keratotic epidermal tumour, common among workers in pitch and coal tar derivatives. ... See: pitch-worker's cancer. ... (05 Mar 2000) ... 
a precancerous epidermal tumor seen in persons working with pitch and coal tar derivatives.
Type: Term Definitions: 1. a precancerous keratotic epidermal tumor, common among workers in pitch and coal tar derivatives. See: pitch-worker's cancer