HEPATOID ADENOCARCINOMA OF THE LUNG - REPORT OF A CASE OF AN UNUSUAL ALPHA-FETOPROTEIN-PRODUCING LUNG-TUMOR

We report on a rare tumor of the lung characterized by its morphologic hepatoid features and alpha-fetoprotein production. This unusual neop lasm arose in the left lung of a 36-year-old man in whom clinical and radiologic examinations did not reveal any other tumor. The serum leve l of alpha-fetoprotein was measured at 6,090 ng/mL and was parallel to the evolution of the tumor. Despite treatment, the patient died 7 mon ths after the diagnosis. The microscopic appearance of the tumor was t he same as observed in hepatocarcinoma and hepatoid adenocarcinoma of the ovary or the stomach, with a tubular, papillary, or trabecular pat tern. Periodic acid-Schiff-positive hyaline globules were numerous, an d tumor cells showed immunohistologic positivity for alpha-fetoprotein and carcinoembryonic antigen. This lung adenocarcinoma was first desc ribed by Ishikura et al. in 1990 and was named hepatoid lung adenocarc inoma. Like the rare hepatoid carcinoma of the gallbladder, the pancre as, the ampulla of Vater, the renal pelvis, and the bladder, the exact histogenesis and the prognosis of this type of lung tumor are not yet known.