Endometrioid Carcinoma of the Fallopian Tube Resembling an Adnexal Tumor of Probable Wolffian Origin

Six adenocarcinomas of the fallopian tube that resembled the female adnexal tumor of probable wolffian origin are described. The tumors, which occurred in patients from 38 to 66 (average 55) years of age, typically formed intraluminal masses. One was an incidental finding on microscopic examination. On microscopic examination, the tumors were characterized by a predominant pattern of small, closely packed cells punctured by numerous glandular spaces, which were typically small but occasionally were cystically dilated. Many of the glands contained a dense colloid-like secretion that was positive with the periodic acid-Schiff stain. Small amounts of intracellular mucin were present in all cases. In the solid areas of three cases, spindle cells that focally formed concentric whorls were present. In all cases, small numbers of tubular glands typical of endometrioid adenocarcinoma were identified. The cytologic atypia and mitotic activity of the tumors were variable, but they exceeded that usually seen in wolffian duct tumors. The evidence indicates that this neoplasm represents an unusual form of endometrioid adenocarcinoma. It is important that it is distinguished from a tumor of wolffian duct origin.