Atypical peripheral (bronchiolar) adenoma of the lung.

An unusual type of peripheral adenoma of the lung in a 52-year-old Japanese female was reported. Clinically the patient showed no sign of hormonal disturbances . Surgically removed tumor was 7 cm in diameter and histologically consisted of ovoid or fusiform cells of spindling and rather bland character , which were arranged prominently in solid nesting pattern suggestive of neurilemmoma or chemodectoma. However, a direct transition from the bronchiolar epithelium to the tumor cell nesting was confirmed by semi-serial sections. In comparison with the usual type of pulmonary adenomata, histological characteristics in this case were discussed in reference to the histogenesis based on constitutional differences between Japanese and Anglo-American races.