Morphologic analyses of positive peritoneal cytology in endometrial carcinoma.

OBJECTIVE: To investigate the relationship between the morphologic features of endometrial adenocarcinoma cells in peritoneal fluids (effusions and washings) and macroscopic intraabdominal adenocarcinoma at laparotomy as well as prognosis. STUDY DESIGN: Seventy-one patients with endometrial adenocarcinoma who showed positive peritoneal cytology at laparotomy were clinically divided into three groups: 25 patients with macroscopic neoplastic seeding in the peritoneal cavity (type 1), 38 patients without macroscopic peritoneal metastasis who survived with no evidence of disease (type 2) and 8 patients without macroscopic peritoneal metastasis who later developed recurrence of adenocarcinoma (type 3). Morphologic features of the adenocarcinoma cells in smears of peritoneal fluids were examined. RESULTS: Most of the smears from type 1 patients showed moderate to high cellularity, scalloped edges of cell clusters and isolated adenocarcinoma cells, whereas these features were seldom observed in type 2 patients. Although not all type 3 patients demonstrated these three features, patients in the series whose specimens exhibited none of the three features did not show any peritoneal lesions or have a recurrence of their disease. CONCLUSION: The finding of endometrial adenocarcinoma cells exhibiting high cellularity, scalloped edge of cell clusters and isolated cells in smears of peritoneal fluid is associated with the presence of intraabdominal macroscopic metastatic lesions and could be regarded as a risk factor for intraabdominal recurrence of carcinoma.     

Diagnostic usefulness of endometrial aspiration cytology for endometrial cancer cases with normal curettage findings

OBJECTIVE: To determine whether endometrial aspiration cytology is useful for endometrial cancer cases with normal endometrial curettage findings. STUDY DESIGN: Eleven cases in which endometrial cancer could be detected by endometrial aspiration cytology but not endometrial curettage were classified into 2 groups by cancer locus, on the endometrial surface (A) or in the myometrium (B). A clinicopathologic and cytologic analysis was performed to compare the 2 groups. RESULTS: Five cases had cancer lesions localized at the fundus and one at the isthmus (group A). The other 5 had lesions localized in the myometrium (group B). The myometrium invasion was beyond half the myometrium in group B and within half in group A. It required > 2 cytologic examinations for a definitive diagnosis in 33.3% of group A and 80.0% of group B. The endometrial cytology differed clearly between the groups: large clusters of malignant cells with a dirty background (group A) vs. small clusters with a clean background (group B). The log-rank test revealed that group B had significantly poorer prognoses than did group A despite nearly the same rate of stage I/II cases in the 2 groups (p = 0.004). CONCLUSION: Endometrial aspiration cytology was useful for endometrial cancer cases with normal curettage findings as part of early detection. However, the cytologic diagnosis did not indicate good prognoses in the cases of cancer localized in the myometrium.     

Endometrial aspiration cytology for diagnosis of peritoneal lesions in extrauterine malignancies

OBJECTIVE: To evaluate the usefulness of endometrial aspiration cytology for assessing malignant cells of extrauterine origin. STUDY DESIGN: Endometrial cytology was performed on 224 patients with primary ovarian cancer, 10 with fallopian tube cancer and 45 with peritoneal tumors. RESULTS: Of 224 patients with ovarian cancer, 53 (23.7%) had positive endometrial cytology. Positive rates were: stage I, 4.3%; stage II, 25.0%; stage III, 39.7%; stage IV, 34.5%. Histologic positive rates were: serous, 28.7%; mucinous, 11.4%; clear cell, 23.1%; endometrioid and unclassifiable adenocarcinomas, 28.0%. Of 5 patients with ovarian cancer, 2 were asymptomatic, but aspiration cytology was positive. Of 10 patients with fallopian tube cancer, 9 (90.0%) had positive endometrial cytology. The positive rate on endometrial cytology was 56.7% in stomach cancer, 60.0% in breast cancer and 20.0% in colon cancer. Of 1,209 women with stomach cancer, 30 (2.4%) displayed ovarian metastasis. Of these, 7 (23.3%) had Krukenberg's tumor; endometrial cytology was positive in 1 (14.3%). In 7 of 17 patients with positive endometrial cytology, clinical diagnosis was made before stomach cancer therapy. CONCLUSION: Endometrial aspiration cytology is useful for identifying nongynecologic malignant cells, diagnosing ovarian and fallopian tube cancers, and determining peritoneal dissemination and metastasis originating from gastrointestinal and breast cancers.     

Diagnosing endometrial carcinoma with cervical involvement by cervical cytology

OBJECTIVE: To assess the relationship of a cervical cytologic diagnosis based on number, size and degeneration of malignant clusters and necrotic background to cervical involvement of endometrial carcinoma. STUDY DESIGN: Cervical smears of 53 women with endometrial carcinoma were evaluated for cervical involvement. The cytologic diagnosis was compared with actual involvement, and accuracy was calculated. Retrospectively, cytologic features, including number, size and degeneration of malignant clusters and necrotic background, were analyzed in involved and noninvolved cases. RESULTS: Cervical involvement was confirmed in 15 patients (28.3%). The number and size of malignant clusters in the involved cases were significantly larger than those in the noninvolved cases (P < .001 and < .01, respectively). The proportion of degenerated malignant cells and necrotic background in involved cases were significantly higher than those in noninvolved cases (P < .05). Cytologic diagnosis had a sensitivity and specificity of 62.5% and 86.8%, respectively. CONCLUSION: Cervical smears of involved cases revealed a large number and large size of malignant clusters. These findings support cytologic diagnosis based on number, size and degeneration of malignant cells and necrotic background. Cervical cytology is useful to exclude cervical involvement because of its high specificity and can help detect cervical involvement because of its moderately high sensitivity.     

Cervical and peritoneal fluid cytology of uterine sarcomas

OBJECTIVE: To study the cytologic features of uterine sarcoma. STUDY DESIGN: The pathology records of 102 patients with uterine sarcoma were reviewed. Four patients, including one case of leiomyosarcoma (LMS), one high grade stromal sarcoma (HGSS) and two malignant mixed müllerian tumor (MMMT), had abnormal cervical and/or peritoneal cytologic findings. Three abnormal cervical smears and two abnormal peritoneal fluids from these patients, including immunohistochemically stained sections of cell block, were reviewed. RESULTS: The diagnostic cells appeared in clusters or in isolation. They had enlarged and hyperchromatic nuclei. Occasional mitotic figures were seen. The cells were considered suspicious for malignancy in cervical smears of HGSS and in the peritoneal fluid of LMS. Adenocarcinoma cells were identified in both the cervical smear and peritoneal fluid of one patient with MMMT. Atypical cells were found in another patient with MMMT. CONCLUSION: Positive cervical or peritoneal cytology is uncommonly detected in association with uterine sarcomas. Even when abnormal cells are found, it may be difficult to give a definitive diagnosis of uterine sarcoma based directly on the cytomorphologic characteristics of cervical or peritoneal smears. However, such a possibility should be kept in mind by the cytopathologist to avoid missing the diagnosis.     

Papillary breast lesions diagnosed on cytology. Profile of 65 cases

OBJECTIVE: To analyze the cytologic features of nipple discharge and fine needle aspiration (FNA) cytologic smears from breast lesions reported as showing papillary features and to correlate them with histopathologic features. STUDY DESIGN: The study group consisted of FNA smears and/or nipple discharge smears from 65 breast lesions diagnosed on cytology as duct papilloma, papillary lesion, fibrocystic condition, fibroadenoma, papillary neoplasm or papillary carcinoma. Cytomorphologic features assessed included cellularity, cell pattern (clusters, papillary, 3-dimensionality, etc.) and cell characteristics (monomorphism, pleomorphism, apocrine change, plasmacytoid features). Histological material was available for review and cytohistologic correlation in all cases. RESULTS: Forty-six specimens were FNA smears, and 16 were nipple discharge smears; in 3 cases FNA and nipple discharge cytologic smears were available for review. Cytologic study could predict the presence of a papillary pattern in all neoplasms with pure or focal papillary differentiation. There was an overlap in cytomorphologic features between papillary and nonpapillary benign lesions as well as between benign and malignant papillary neoplasms. Frank blood in the aspirate, cell dissociation and atypia, however, were more frequent in the last. CONCLUSION: Overlap of cytologic features in nonneoplastic and neoplastic benign papillary lesions and between benign and malignant papillary neoplasms necessitates histologic evaluation in all cases diagnosed as papillary on cytology. Since 49.2% of lesions showing papillary features on cytology prove to be malignant, all cases reported as papillary on cytology should be excised urgently for histologic assessment.     

Peritoneal cytology in uterine papillary serous carcinoma.

OBJECTIVE: To highlight the significance of positive peritoneal cytology in uterine papillary serous carcinoma (UPSC). STUDY DESIGN: Seventeen consecutive UPSC cases with peritoneal cytology from 1993 to 1997 were reviewed and compared with the original cytologic diagnosis and extent of tumor involvement in tissues. RESULTS: Of the 17 post-menopausal women with UPSC, 11 had early-stage tumors (clinical stage I and II); three cases (27%) with positive peritoneal cytology were upgraded from at least International Federation of Gynecologists and Obstetricians stage IA to IIIA. No change in surgical stage was noted in four of six (67%) advanced cases with positive peritoneal cytology. The review diagnoses of peritoneal cytology did not differ from the original diagnoses. CONCLUSION: The features of UPSC in peritoneal cytology are those of a high grade malignancy and may be shared by tumors with similar histology from other sites. The malignant features are readily identified, but the site of origin may not be completely ensured. Positive peritoneal cytology upgrades the surgical stage of early-stage UPSC cases and helps with prognostication and treatment. One case with positive washings but without residual tumor probably represented early spread and/or multicentric origin of the tumor.     

Clinico-cytological study of uterine papillary serous carcinoma

OBJECTIVE: The aim of this study was to determine whether or not we could distinguish uterine papillary serous carcinoma (UPSC) from other types of endometrial cancer by cytology. METHODS: We examined the cytological findings of the endometrium from five cases with UPSC and compared them with 10 cases with endometrioid adenocarcinoma, grade 1 (G1). A morphometric analysis was performed. Cytological samples from the cervix and ascites of the patients with UPSC were also reviewed. RESULTS: All five patients had FIGO stage III and IV tumours. Three patients died of the disease and two are still alive with disease. The tumour cells of UPSC tended to be shed in papillary clusters with a tumour diathesis. Psammoma bodies were seen only in UPSC. The frequency of irregular-shaped nuclei, membrane thickness and eccentric nuclei in UPSC was higher than in G1. The chromatin pattern was coarsely granular, and both anisonucleosis and bare nuclei were prominent in UPSC. Cytomorphometrically, the maximum diameter of the nuclei in UPSC was significantly greater than that in G1. The nucleoli were also more often seen in UPSC than in G1. The findings of the nuclei and nucleoli in the cervical and peritoneal fluid cytology closely resembled those in endometrial smears. The features of the cervical smears and peritoneal fluid cytology were different from those of endometrial cytology regarding clear background and small clusters of cells. CONCLUSION: As the endometrial cytology findings accurately suggested the histological diagnosis of UPSC, the diagnosis of UPSC was confirmed in this study by endometrial cytology. The cytological diagnosis of UPSC should be based on the findings of tumour diathesis, psammoma bodies and papillary clusters composed of tumour cells with enlarged nuclei and numerous nucleoli.     

The cytology of vaginal, cervical and endometrial smears obtained at the time of embryo transfer during in vitro fertilization

Seventy-four women enrolled in an in vitro fertilization (IVF) program had cytologic smears of the vagina, cervix and endometrium obtained at the time of embryo transfer (ET). Of these, 68 vaginal, 46 cervical and 25 endometrial smears were available for cytologic examination. Of the 68 vaginal smears, 4% showed a proliferative pattern, 40% were early secretory and 56% were advanced secretory. The 46 cervical smears demonstrated a delayed hormonal effect, with 70% showing a proliferative pattern, 23% early secretory and 7% advanced secretory cytology. Endometrial cells were obtained only when the Jones catheter, which has a side opening, was used. Twenty-two patients had both vaginal smears and suitable endometrial smears. Of these, 8 of the 9 patients with early secretory vaginal cytology had secretory endometrium while 10 of the 12 patients with mid-secretory vaginal cytology had secretory endometrium. The value of endometrial cytology in predicting conception following IVF-ET is unknown. It seems, however, that a good correlation exists between endometrial and vaginal cytology and that the latter may be of value as an additional, noninvasive tool for the evaluation of endometrial development.     

Endocyte endometrial smears in the cytodiagnosis of endometrial carcinoma

The cytologic diagnosis of endometrial cancer using material obtained with the Endocyte endometrial sampler was assessed for 874 patients. The samples obtained were smeared directly on slides for fixation and staining; the smears were more difficult to assess than cervicovaginal smears, however, due to the presence of blood, the small size and density of the cells and the flattened three-dimensional architecture of the tissue fragments obtained. Only 8.2% of the samples were classified as inadequate; repeat sampling in some of those cases produced diagnostic material. All 12 cases of carcinoma (including one case in a woman less than 40 years of age) were diagnosed by cytology as malignant; however, the original cytologic sample in one of those cases was inadequate. For the diagnosis of benign versus malignant, cytology had a sensitivity of 92%, a specificity of 100% and predictive value of 100%. Cytology also diagnosed as suspicious the smears from 5 of 13 cases of endometrial hyperplasia and 2 of the 9 cases of endometrial polyps. The cytologic findings for benign and malignant samples are described and illustrated in detail. Relative to other endometrial sampling devices, the Endocyte is inexpensive and was easily used by the gynecologist and well tolerated by the patients, with no complications and minimal discomfort.     

Fine needle aspiration cytology of invasive micropapillary carcinoma of the breast: review of cases in a three-year period.

OBJECTIVE: To describe the fine needle aspiration cytology findings of invasive micropapillary carcinoma and correlate them with the histologic appearance. STUDY DESIGN: We reviewed the cytologic features of three cases of pure invasive micropapillary carcinoma in the files of Pamela Youde Nethersole Eastern Hospital from 1998 through 2000. Immunohistochemical study for epithelial membrane antigen was performed retrospectively on the cell block sections. Ultrastructural examination was also carried out on one of the cases. RESULTS: Two of the tumors were at pathologic stage II, and the remaining case was at stage III. Ipsilateral axillary lymph node metastases with similar morphology were seen in two of them. Cytologically, the smears were of moderate cellularity and composed of three-dimensional tumor cell balls, abortive and sometimes branching papillae, angulated tumor cell clusters, morules and occasional acini. Some of the tumor cell balls possessed scalloped borders. Focally, the tumor morules clustered together and were separated from each other by small, slitlike spaces. A small number of isolated malignant cells was also present in the background. The cell block sections showed mainly dispersed acini of tumor cells. The "reverse polarity" highlighted in histologic sections by immunohistochemical study for epithelial membrane antigen was not consistently demonstrated in the cell block material. Ultrastructural examination confirmed the focal presence of surface microvilli on the periphery of the tumor cell morules. CONCLUSION: Invasive micropapillary carcinoma of the breast possesses some subtle but distinctive cytologic features. With the help of cell block morphology and ancillary techniques, the preoperative suspicion of this rare subtype of ductal carcinoma, which carries a high propensity for lymphatic permeation, is possible.     

Usefulness of endometrial aspiration cytology for the preoperative diagnosis of ovarian carcinoma

OBJECTIVE: To evaluate the usefulness of endometrial aspiration cytology for the preoperative diagnosis of ovarian carcinoma. STUDY DESIGN: A total of 210 patients with ovarian carcinoma were investigated by endometrial aspiration cytology. RESULTS: Fifty-five of 210 patients (26.2%) had positive endometrial aspiration cytology. The positive rates of endometrial cytology were 3.9% in stage I, 23.8% in stage II, 36.5% in stage III and 53.3% in stage IV. When classified by histologic type, the positive rates of endometrial cytology in patients with serous adenocarcinoma, mucinous adenocarcinoma, clear cell adenocarcinoma, undifferentiated carcinoma and yolk sac tumor were 38.9%, 11.8%, 21.1%, 16.7% and 16.7%, respectively. One hundred twenty-eight of 210 patients (61.0%) were positive on peritoneal cytology, and 54 of these 128 cases (42.2%) were also positive on endometrial cytology. The positive rates of endometrial cytology were especially high in patients with serous adenocarcinoma (51.2%) and those with clear cell adenocarcinoma (40.0%) among those who were positive on peritoneal cytology. Of 74 patients who were negative on peritoneal cytology, only one (1.4%) with mucinous adenocarcinoma had positive endometrial cytology. Hysterectomy was performed on 130 patients, and the positive rate of endometrial cytology was 100% in 4 patients with endometrial invasion and 15.9% in 126 cases without invasion. CONCLUSION: Endometrial aspiration cytology can detect ovarian carcinoma cells not only in patients with endometrial involvement but also in patients with positive peritoneal cytology. Endometrial aspiration cytology appears to be useful for the preoperative diagnosis of ovarian carcinoma.     

Clinicopathologic relevance of asymptomatic endometrial carcinoma

OBJECTIVE: To assess whether screening asymptomatic women is significant for early detection of endometrial carcinoma. STUDY DESIGN: We compared the clinicopathologic findings and prognoses of 21 asymptomatic patients with 427 symptomatic patients with endometrial carcinoma. RESULTS: The incidence of asymptomatic endometrial carcinoma was 4.7%. Nineteen of 21 asymptomatic patients with endometrial carcinoma were found by cytologic screening for endometrial cancer. There was a statistical difference in the histopathology and depth of myometrial invasion between the asymptomatic and symptomatic groups. However, no statistical differences were found in tumor grade, lymph node metastasis, adnexal metastasis, cervical invasion, peritoneal cytology, surgical stage and patient age. Univariate analysis showed that the presence or absence of symptoms was not related to survival. CONCLUSION: The detection of asymptomatic endometrial carcinoma is not related to a reduced mortality rate. Screening asymptomatic women for endometrial carcinoma is not recommended.     

Basement membrane material and tigroid background in a fine needle aspirate of clear cell adenocarcinoma of the cervix. A case report

BACKGROUND: Although cytologic findings of clear cell adenocarcinoma of the female genital tract have been reported sporadically, the background on the smear has received little attention. CASE: A 16-year-old female had a large, necrotic mass in the cervix. As cervical brushing cytology and a punch biopsy of the mass could not make a definitive diagnosis, fine needle aspiration cytology was performed from the mass. The smears revealed loose, three-dimensional clusters and sheet arrangements of atypical cells. Dispersed atypical cells were also seen. The atypical cells were large and had abundant, weakly stained cytoplasm and round or oval nuclei with large nucleoli. There were a few tumor cells with clear cytoplasm and distinct cell borders in Papanicolaou-stained smears. The background in Diff-Quik-stained smears revealed a tigroid background and basement membrane material. CONCLUSION: The malignant tumor, revealing both a tigroid background and basement membrane material, seems to have been clear cell adenocarcinoma. Both features are diagnostic clues to clear cell adenocarcinoma in the female genital tract. Our case indicates that aspiration cytology is also an effective method of diagnosing a cervical tumor when the tumor is polypoid and the surface is extensively necrotic.     

Effects of tamoxifen on cervicovaginal smears from patients with breast cancer

OBJECTIVE: To evaluate the effect of tamoxifen on cervicovaginal epithelium and determine the value of cervicovaginal smears in identifying patients at risk for endometrial carcinoma. STUDY DESIGN: A group of 48 women with prior breast cancer were divided into three groups: A, tamoxifen-treated patients who developed endometrial carcinoma (n = 20); B, patients with endometrial cancer not treated with tamoxifen (n = 22); and C, tamoxifen-treated patients with no endometrial carcinoma (n = 16). A total of 114 cervicovaginal smears from these patients were evaluated for maturation index, histiocytes, benign and malignant endometrial cells, reactive cellular changes and microorganisms. All patients treated with tamoxifen had received doses of 10 mg twice daily. RESULTS: The maturation index was increased in tamoxifen-treated patients (A and C) versus nontreated patients (B) P < or = .001). The number of cases with endometrial cells was significantly higher in smears of treated patients who developed endometrial cancer (A) as compared to groups B and C (P = .01 and .02, respectively). Histiocytes were also significantly increased in the two groups that subsequently developed endometrial carcinoma (A and B) as compared to the group that did not (group C) (P = .02). There was no significant difference in the presence of reactive cellular changes between the three groups. CONCLUSION: Patients treated with tamoxifen exhibited a partial estrogenic effect in their smears regardless of whether they developed endometrial cancer. However, the presence of endometrial cells in the smears indicated a higher risk of endometrial adenocarcinoma.     

Bronchial cytology in pleural mesothelioma. A report of 3 positive cases, including 1 diagnosed initially on bronchial brushings

OBJECTIVE: To evaluate retrospectively the value of bronchial aspiration cytology in patients with histologically proven pleural mesothelioma, reappraising positive smears in light of conventional microscopic features and, when feasible, immunocytochemical investigations. STUDY DESIGN: In 3 cases of mesothelioma with bronchial brushings positive for malignant cells, the cytologic features were correlated with the histologic findings. RESULTS: Salient microscopic features included scant to moderate cellularity arranged in micropapillary clusters, morular aggregates with scalloped borders and isolated malignant cells. Intercellular clear spaces or windows suggesting a brush border on cell membranes were also noted. In cases with available material, immunocytochemistry was positive for keratins, epithelial membrane antigen and calretinin and negative for carcinoembryonic antigen. All the cases were histologically confirmed epithelial mesotheliomas. CONCLUSION: In rare cases, pleural mesothelioma cells are shed within the airway lumina and can be detected in bronchoscopic cytology specimens. Cytologic features seem comparable to their analogues in pleural effusions. Although no single criterion appears diagnostic, their combined documentation could ensure correct interpretation, especially if supported by a limited immunocytochemical panel.     

Cervicovaginal and endometrial cytology in ovarian cancer

The clinical significance of cytologic examination was studied in 114 patients with ovarian cancer who had received preoperative cytologic examinations. The overall positive rate of the cytologic examinations was 26.3% (30 of 114): 22 (19.3%) of the 114 cases had positive cervicovaginal smears while 13 of 31 endometrial aspiration smears (41.9%) were positive. The positive rate was not related to the volume of ascites but rather to its presence or absence. Thus, if ascites was observed, the positive rate was about 2.1 times higher than if it was absent. In two of four cases of ovarian cancer with no endometrial invasion but a positive cytologic examination of ascitic fluid, fallopian tube specimens contained cancer cells; this suggests that ovarian cancer cells may reach the cervix and/or vagina by passing through the fallopian tube, particularly if ascites is present. Since cytologic examination, especially of endometrial aspiration smears, shows a high positive rate if ovarian cancer cells are observed in the abdominal cavity, cytology should be used as an important ancillary method for the assessment of ovarian cancer.     

Abrasive bronchial brushing cytology. A preliminary study of 200 specimens for the diagnosis of neoplastic and nonneoplastic bronchopulmonary lesions

Two hundred subjects with chronic respiratory symptoms with a suspicion of malignancy were selected for bronchial brushing cytology. Prior sputum examination had shown malignant squamous cells in two cases only. The cytologic appearances of the brushing smears were divided into five categories: 41 (20.5%) smears with positively malignant cells; 20 (10%) smears predominantly showing chronic inflammatory features; 31 (15.5%) smears with mainly acute inflammatory changes; 60 (30%) smears with normal cytologic features; and 48 (24%) smears unsatisfactory for cytologic interpretation. Thirteen patients with a positive cytology had a positive tissue biopsy for malignancy. Among the group with chronic inflammatory changes, acid-fast bacilli were identified in nine cases, and one smear showed frank tuberculous granuloma. In the unsatisfactory group, two cases showed malignant cells in the postbrushing sputum. There was one false-negative report for malignancy in the entire study. This study confirms the sensitivity and accuracy of bronchial brushing cytology in the diagnosis of various bronchopulmonary lesions, especially malignancy and pulmonary tuberculosis, in India.     

Cytopathology of peritoneal endometriosis caused by ruptured ovarian cysts

The cytopathologic features of two cases of peritoneal endometriosis (secondary to ruptured ovarian endometrial cysts) are described. Both patients presented with abdominal distension and tenderness and were clinically thought to have an abdominal tumor. Preoperative cytologic examination of peritoneal fluids gave a diagnosis of endometriosis in both cases. The endometrial tissue was present in the smears as honeycombs, syncytia and tight clusters of both epithelial and stromal cells. Subsequent surgery confirmed the cytodiagnosis in both cases. These cases emphasize the need to include endometriosis in the differential diagnosis of peritoneal effusions, especially in women.     

Atypical glandular cells of undetermined significance favor endometrial origin. Criteria for separating low grade endometrial adenocarcinoma from benign endometrial lesions

OBJECTIVE: To evaluate cytologic criteria for separating atypical glandular cells of undetermined significance favor endometrial origin (AGUS-EM), on Papanicolaou-stained (Pap) smears into favor benign and favor malignant categories. STUDY DESIGN: All patients who had a Pap smear diagnosis of AGUS-EM, not further qualified, followed by tissue follow-up were identified from the surgical pathology and cytopathology files from January 1992 through December 1996. The Pap smears were scored blindly for the presence or absence of 40 cytologic criteria, and univariate analysis was performed to determine which criteria were most indicative of malignancy by tissue follow-up. RESULTS: The presence of an atrophic smear, nuclear size greater than twice that of an intermediate cell nucleus and absence of clusters with irregular borders were highly indicative of adenocarcinoma, although other criteria were also helpful in identifying malignancy. CONCLUSION: There are no combinations of cytologic criteria that definitely separate AGUS-EM cases into those with benign or malignant findings on follow-up. However, some isolated criteria were useful in the differential diagnosis in a [table: see text] significant number of cases.