Abstract
A 68-year-old man was admitted for the evaluation of abnormal mass shadow on the chest X-ray film and was diagnosed as having ACTH-producing tumor originated in thymus after endocrinologic examinations. The left thoracotomy revealed this case was inoperable because of the invasion to surrounding organs. Histologic specimens were obtained at the biopsy and the autopsy, and utilized for light and electron micro scopic observations.
Under light microscopy the Glimerius stain was positive. Histologic diagnosis was carcinoid tumor originated from thymus. Ultrastructurally, in biopsied specimen light and dark cells were found. The former was abundant with mitochondria and possessed many neurosecretory granules. In autopsied specimen, numerous granules were observed and these were identified as hormonal granules containing ACTH and MSH.
