“…Nishino and Wang, compiling a series of retrospective studies, found malignancy in 55% of patients in subcategory NA versus 22% in subcategory AA. In subsequent studies, these rates were, respectively, 52.7% versus 6.8%, 51% versus 8.1%, 35% versus 10%, 65.8% versus 14.3%, and 36.8% versus 14.7% . To our knowledge, the only prospective study available showed malignancy in 41.3% of cases of subcategory NA and in 10.8% of subcategory AA …”