Histological background for cytological diagnosis ASC-H

—A present state and problems—

Abstract

The histological background for the cytological diagnosis of high-grade squamous intraepithelial lesions (ASC-H) was analysed using a parallel observation. Although ASC-H is defined as atypical squamous epithelium which cannot exclude high-grade squamous epithelial lesions (HSILs) and includes a wide range of pathological changes, the following four categories were found important as background lesions : 1. Atypical atrophic squamous epithelium, 2. Atypical immature (squamous) metaplasia, 3. Carcinoma in situ (CIS) (when accepted as Cell Groups [CGs] in cytological diagnosis), and 4. Poorly differentiated type adenosquamous carcinoma. Although histologically uncertain lesions are included in ASC-H, with better knowledge about those histological lesions and CGs, cytologists may be able to give ASC-H cases, at least in part, more distinct or accurate diagnoses.