The line means the author doesn't know what "99% reduction based on histology" means, where histology is more accurate than appearance. Nor does he get that "180 days"..."no reoccurrence" means the mice went 15 human years with no new lesions.
The data I think the author is talking about:
» Prurisol (10 mg/kg PO twice/ day x 21 days)
» 84% reduction in lesion appearance
» 99% reduction in lesions based on histology
» 96% reduction in serum PRINS
» 87% reduction in serum IL-20
» No reoccurrence of lesions within 180 days
The numerical data from this are slightly less impressive than the pictures, and there may be unanswered questions about the role of experimental procedures (such as prior irradiation) on the outcomes.