leuco is incorrectly written, and should be written as "Leuko-" being its meaning:
Also leuc-, leucos-, - leuc-, - leuco; prefixes, infixes and suffixes used in Spanish, especially in medical terminology, derived from the Greek word leukos leuke leukon which means white. We are words such as leukemia, leukocyte, leucopatia, leukopenia, leucotermes, melanoleuco
