Increased diagnostic accuracy of atypical glandular cells in cervical liquid-based cytology using cell blocks

The purpose of this study was to reduce the number of diagnoses of atypical glandular cells (AGC). Residual material from the cervical ThinPrep® samples (Hologic, Marlboruogh, MA, USA) was used for cell blocks (CB) and immunohistochemistry (IHC).

In 2007 there were 87 patients (0.12% of tests) with AGC on liquid-based cytology (LBC) in the Leiden Cytology and Pathology Laboratory (LCPL) using the Bethesda System 2001 (TBS). CB with IHC was used for 26 of these cases. The vials still containing the brush (Cervex-Brush(®) Combi) were placed in a shaker for 10 minutes to dislodge the material trapped between the bristles. The residual sampling fluid was used to prepare paraffin sections (Shandon Cytoblock(®)) stained with Papanicolaou and immunostaining.

Four of five cases with AGC not otherwise specified (NOS) were diagnosed with CB/IHC as benign mimics (endometrium, tubal metaplasia, follicular cervicitis, microglandular hyperplasia) and one of four with AGC-favour neoplasia (FN) (endocervical polyp). In one of five cases with AGC-NOS and in two of seven with AGC-FN, CIN3 was found on subsequent histological biopsy. Of six cases diagnosed as adenocarcinoma in situ (AIS) on LBC with CB/IHC the diagnosis was confirmed in four; one was adenocarcinoma and one glandular atypia. Of eight cases diagnosed as adenocarcinoma on cytology and CB/IHC, the diagnosis was confirmed in three. The other five cases were found to be one each of AIS, squamous cell carcinoma, CIN3, CIN2 with glandular atypia, and cervical endometriosis.

By reducing the number of benign mimics of AGC, we achieved a high proportion (16/26; 61.5%) of neoplastic or preneoplastic lesions (glandular or squamous) on histological outcome potentially avoiding colposcopy. Histological biopsy verification by the gynaecologist is needed for final diagnosis of AGC-FN, AIS and adenocarcinoma.