In another retrospective study of 15 cases of pulmonary papillary adenoma, two had malignant manifestations, including tumor cells of variable size, deep nuclear chromatin, easily visible nuclear schizophrenic images, partial infiltration of tumor cells in the interstitium, and a Ki-67 proliferation index exceeding 25% in the heterogeneous region [3]. Here, MKI67 is linked to neoplasm.