Transitional cell carcinoma of the fallopian tube: a light and electron microscopic study.

Carcinomas other than adenocarcinomas are extremely rare in the fallopian tube. We report a case of a malignant neoplasm of the fallopian tube with histological features of transitional cell carcinoma that presumably arose from an extraluminal region of the tube. A 57-year-old postmenopausal woman with vaginal bleeding was found to have a left adnexal tumor. Exploratory laparotomy revealed a left tubal tumor with a metastatic nodule on the rectal surface. Histologically, the tumor surrounded the lumen of the left fallopian tube and was composed of cells with "coffee-bean"-like nuclei arranged in solid nests without keratinization. No abnormalities were found in the right tube, ovaries, or uterus. Electron microscopy revealed the tumor cells to have nuclei with deep nuclear indentations, cytoplasmic tonofilaments, and intercellular spaces with prominent interdigitations of the cell membrane. In addition, several tumor cells with protruding microvilli formed abortive lumina. These histological and ultrastructural features were consistent with the diagnosis of transitional cell carcinoma.