Value of histiocyte detection in Pap smears for predicting endometrial pathology. An institutional experience

OBJECTIVE: To determine the clinical implications of the finding of histiocytes in Pap smears in 1 patient population. STUDY DESIGN: The medical records and Pap smears which the presence of histiocytes was mentioned in the diagnosis between August 1996 and August 2001 were reviewed in conjunction with follow-up surgical findings. The positive predictive value (PPV) for significant endometrial pathology for the isolated finding of histiocytes on Pap smear was determined. RESULTS: Of the 238,225 women screened over a 60-month period, 325 were reported to have histiocytes in their Pap smears. Of them, 238 (73.2%) had subsequent endometrial sampling, hysterectomy or both, and follow-up Pap smears. Two hundred seven smears (87%) failed to disclose endometrial pathology. Thirty-one cases (13%) resulted in significant histopathologic findings, including 12 uterine malignancies, 8 endocervical polyps, 7 endometrial polyps, 2 submucosal leiomyomata, 1 simple hyperplasia without atypia and 1 case of tamoxifen-related changes. Upon review of the clinical records, 58% (18/31) of those patients had other significant clinical and/or cytologic findings. Five of the 18 patients (27.8%) had associated postmenopausal bleeding, 11 had additional abnormal Pap smear findings (atypical glandular cells, 6/18, or 33.3%; endometrial cells, 5/18, or 27.8%), and another 2 had both postmenopausal bleeding and atypical glandular cells (2/18, or 11.1%). The PPV for significant uterine pathology for women with the isolated finding of histiocytes on a Pap smear was 5.5% and 60% with additional clinical and/or Pap smear findings. The PPV for endometrial cancer was 1.3% in women with the isolated finding of histiocytes on a Pap smear but 20% for women with histiocytes and additional clinical/or Pap smear findings. CONCLUSION: Based on the findings of this study and recently published data, we conclude that the isolated finding of increased histiocytes in the absence of postmenopausal bleeding, endometrial cells or atypical glandular cells on a Pap smear is a poor indicator of uterine disease.