USE OF THIN-LAYER PREPARATIONS FOR GYNECOLOGIC SMEARS WITH EMPHASIS ON THE CYTOMORPHOLOGY OF HIGH-GRADE INTRAEPITHELIAL LESIONS AND CARCINOMAS

Thin-layer (TL) technology can improve the detection rare for sguamous lesions of the uterine cervix. Studies to date have underrepresented high grade lesions and malignancies The present study utilized a patie nt population at high risk for such lesions in order to analyze the pe rformance of TL procedures in this group, and in addition, to assess t he similarities and differences in morphologic appearances of specimen s prepared by the two methods. Conventional (CS) and thin-layer smears (TLS) were made in parallel from the same specimen. Each slide was ex amined in a blinded fashion. Diagnoses were compared and morphologic o bservations made. Two hundred fifty-nine cases were included, of which 32 (12%) were high grade dysplasias (11) or carcinomas (21). Thirty f ive (14%) were atypical or low grade dysplasias. There was exact corre lation between Bethesda classification in 231 cases (89%). Of the 21 c arcinomas identified, 19 (91%) were present on each preparation. Two c ases of endometrial adenocarcinoma were missed on unsatisfactory or ne gative TLS. One case of squamous cell carcinoma was called high grade sguamous intraepithelial lesion (HGSIL) on TLS while the CS was unsati sfactory. Three cases called atypical glandular cells (AGCUS) on TLS, and negative on CS, showed HGSIL (1) or no lesion (2) on followup. Mor phologic features of low grade lesions were virtually identical on bot h preparations. Distinct features were noted on TLS in the high grade lesions. These included smaller appearing nuclear areas, less distinct nuclear chromatin, thicker three-dimensional groupings, and more isol ated cells. Such findings were most pronounced in the glandular lesion s. With training and experience, these features were easily identified in TL preparations, further documenting the utility of this procedure for use in routine practice. (C) 1996 Wiley-Liss, Inc.