[Predominantly mucous-differentiated acinic cell adenocarcinoma of the trachea].

: Reported in this paper is a predominantly mucous differentiated acinic cell adenocarcinoma of seromucous tracheal glands in a male patient aged 64 years. Local surgical treatment was performed several times within one year and was always followed by recurrence. The naked eye inspection showed a partial polypous appearance of the tumor. Histologically the carcinoma is composed of lobular arranged solid and cribrous cell formations only separated by a sparse fibrous stroma. The tumor is not capsulated, and invasive growth is evident. Large cells with abundant bright cytoplasm and a strongly positive reaction to PAS form the main constituent of the tumor. Signet cell formation sometimes occurs. Electron microscopic examination reveals abundant secretory granules. These cells are in full accordance with mucous cellular elements of adjacent seromucous tracheal glands from which this rare tumor has obviously originated.