Atypical adenomatous hyperplasia of the lung in autopsy cases

Background: Atypical adenomatous hyperplasia (AAH) is a possible precursor lesion of adenocarcinoma of the lung, but very few reports of AAH have focu sed on the autopsy lung. Methods: We intended to clarify the characteristic s of AAH in the general population by using 207 autopsy cases, ranging in a ge from 0 to 90 years old. Results: A total of 179 eligible cases (86.5%) a nd 1265 tissue slides (7.0 per case) was examined independently by two path ologists. One hundred seventy-nine autopsy cases consisted of 125 males and 54 females, whose median ages were 38 (range 0-90) and 31 (range 0-81) yea rs old, respectively. AAH was microscopically found in five of 179 autopsy cases (2.8%). The male/feniale ratio was 5/0 and age distribution was 52-63 years of age (median 57). One of five cases with AAH harbored esophageal c arcinoma, but the others had no present or previous malignant neoplasm. One of five lesions was high grade and the others were low grade. All five cas es showed positive immunoreactivity for proSP-C, a type II pncumocytes mark er, but not for p53, Ki-67 or CEA. Conclusions: The incidence of AAH was ve ry low in the general autopsy cases, as compared with the previously report ed surgically resected lung and senile autopsy cases, and AAH seems to occu r after middle age in general. (C) 2001 Elsevier Science Ireland Ltd. All r ights reserved.