Adenoid basal carcinoma of the cervix uteri: a case report.

We report a rare case of adenoid basal carcinoma of the uterine cervix, unexpectedly found in a uterus resected for the treatment of cervical intraepithelial neoplasia (CIN) 3. The patient was a 47-year-old Japanese female. She received a total abdominal hysterectomy under a diagnosis of CIN 3 of the cervix. Grossly, there were no significant findings in the surgical specimens. Microscopically, in seven of the 12 blocks of the cervix examined, scattered small nests of uniform small cells, which extended 4 mm below the epithelial surface, with dark nuclei and scant cytoplasm were observed. Peripheral palisading as well as the formation of gland-like or acinar structures were noted. The latter were positive for mucicarmine. Stromal reaction was not obvious. There were also foci of squamous differentiation in some portions of the small nests. Occasional mitoses as well as large atypical cells were also seen in this area. Immunohistochemically, the foci of squamous differentiation were positive for carcinoembryonic antigen. The epithelial surface in other portions showed CIN 3 with crypt extension. Distinction between adenoid basal carcinoma of the cervix and other diseases, such as adenoid cystic carcinoma and squamous cell carcinoma with basaloid features, is important for clinical management because the clinical behavior of adenoid basal carcinoma is less malignant.