[…] Lanfrank takes Notice of Tract. 3. Doct. 3. cap. 18. ſaying, "I have ſeen many who being full of Humours, have made an Iſſue under the Knee, before due Purgation had been premis'd; whence, by reaſon of the too great Defluxion of Humours, the Legs tumified, ſo that the cauterized Place corrupted, and a Cancer (or rather cacoethic Ulcer) was thereby made, with which great Difficulty was cur'd."
Source: wiktionary