We examined the cervicovaginal cytology (PAP) findings in a series of 21 endometrial and 2 cervical carcinosarcomas (CS) [malignant mixed mullerian (mesodermal) tumors] (MMMT). Initial cytology diagnosis was positive for cancer in 14 of 23 cases (sensitivity of 61%); however, CS was correctly identified only 2 times. The remaining 12 cancer diagnoses were carcinomas: 10 adenocarcinomas (4 endometrial, 1 cervical, and 5 adenocarcinomas not otherwise specified), 1 squamous carcinoma, and 1 poorly differentiated carcinoma. Seventeen smears were available for review, all 8 false negative, one unsatisfactory, and 8 of 14 true positive smears. One false negative smear showed rare clusters diagnostic of adenocarcinoma. The remaining 7 false negative smears showed 3 high grade squamous dysplasias (two with additional findings: one showed atypical spindle cells and the other showed endometrial stromal cells), 2 extensive repair changes, and 2 negatives. The unsatisfactory smear showed atypical spindle cells. Review of the 8 true positive smears confirmed malignant spindle cells in the two cases originally identified as CS by cytology and in 3 other cases originally identified as adenocarcinoma. Of 9 smears positive for cancer available for review, 4 showed only carcinoma cells. PAP positive for cancer was associated with high stage at presentation (P less than .025) and recurrent disease (P less than .001) (even among stage I or II patients, P less than .025). PAP positive for cancer showed no association with depth of myometrial invasion, size, grade, or histologic type of carcinosarcoma. The results of this study demonstrate the importance of consultative cytology reporting in which recommendations for appropriate biopsy are included in the report.(ABSTRACT TRUNCATED AT 250 WORDS)