History of High-Resolution Anoscopy

Abstract

High-resolution anoscopy (HRA) is a form of low-resolution anal microscopy currently utilized in the screening and management of anal squamous dysplasia. No randomized controlled trials, national or international guidelines exist on the use of HRA for this purpose. Much of our understanding of this entity has been adapted from the literature on cervical squamous dysplasia, including the technique of HRA itself. Epidemiologic evidence has shown that the prevalence and incidence of anal dysplasia is highest in HIV-positive populations. The history of this technique parallels the evolution of our understanding of anal dysplasia. To understand the history of the use of HRA and its place in the screening and management of anal squamous dysplasia, we discuss key advances in the understanding of human papillomavirus-related squamous dysplasia. We begin with early reports in the field establishing the link between this virus and squamous dysplasia, through the marked increase in anal cancer seen with the onset of the HIV epidemic, the identification of relevant populations at risk, the performance of the test itself, to its use today.

Keywords: anal cancer; anal dysplasia; anal intraepithelial lesions; high-resolution anoscopy.

Fig. 1

Normal exam. Left image: Acetowhite exam. Right image: Lugol's iodine exam. (Left lateral position: L, left; R, right; A, anterior; P, posterior).

Fig. 2

LSIL/AIN I. Left image: Left posterior squamocolumnar junction enhancement and coarse punctation. Right image: Negative iodine uptake (*). (Left lateral position: L, left; R, right; A, anterior; P, posterior).

Fig. 3

HSIL/AIN 2–3. Left image: There are three findings. (1) Right lateral acetowhite enhancement of squamocolumnar junction (*). (2) Left Lateral acetowhite with coarse punctation (+). (3) Right anterior acetowhite enhancement with coarse punctation (**). Right image: (1) Lugol negative right lateral squamocolumnar junction finding (*). (2) Lugol negative left lateral finding (+). (3) Lugol negative right anterior finding (**). (Left lateral position: L, left; R, right; A, anterior; P, posterior).

Fig. 4

AIN 3. Left image: Right anterior increased acetowhite enhancement (*). Right image: Right anterior acetowhite finding with negative Logol's uptake (*). (Left lateral position: L, left; R, right; A, anterior; P, posterior).