Exegesis:
kai egeneto ‘and it happened,’ cf. on 1.8.
en tō einai auton en mia tōn poleōn lit. ‘during his being in one of the towns,’ of Galilee presumably, articular accusative and infinitive. The numeral mia assumes the force of an indefinite article.
kai idou anēr plērēs lepras lit. ‘and behold, a man full of leprosy,’ hence “covered with leprosy” (An American Translation, New English Bible, Willibrord, Bible de Jérusalem and others), stronger than lepros alone (cf. 4.27). For kai idou cf. on 1.20. plērēs, cf. on 4.1. lepra.
kai idōn ton Iēsoun pesōn epi prosōpon edeēthē autou legōn lit. ‘and having seen Jesus, having fallen on his face he besought him saying.’ The two participles idōn and pesōn, both in the aorist, have a different function; idōn refers to an act which precedes everything that follows, pesōn epi prosōpon describes an act which is intimately connected with edeēthē ‘he besought,’ cf. “he prostrated himself in supplication … he said” (The Four Gospels – a New Translation).
deomai ‘to ask,’ ‘to beg,’ ‘to beseech,’ with following direct discourse, here introduced by legōn.
kurie ‘lord,’ cf. on v. 8.
ean thelēs “if only you will” (New English Bible).
katharisai ‘cleanse,’ cf. on 4.27.
Translation:
In one of the cities, or, ‘in a city there,’ ‘in a city of that region.’
Full of leprosy, or, ‘who had leprosy all over’ (Tagalog), ‘suffering badly from leprosy’ (Bahasa Indonesia). For leprosy cf. on “lepers” in 4.27.
He fell on his face, cf. on “he fell down at Jesus’ knees” in v. 8.
Besought, or, ‘begged,’ ‘asked insistently.’
Lord, see on 1.6 (d).
If you will, you can make me clean, or, ‘if (only) you want to make me clean, you have the power to make me clean, or, to do so.’ For to make clean see on “cleansed” in 4.27.
Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.