Anal dysplasia as an incidental finding: the importance of specimen evaluation

The incidence of anal squamous cell carcinoma (SCC) has increased dramatically in the USA. The squamous intraepithelial lesion has been identified as a precursor lesion to SCC, stratifying the abnormality into low grade or high grade. There have been studies on the prevalence of incidentally found SCC in haemorrhoidectomy specimens, but there are no studies to date on the incidence of dysplasia. The purpose of this study was to establish a baseline incidence of dysplasia that provides helpful information for future epidemiological studies.

This is a retrospective review of patients who underwent haemorrhoidectomy from 2005 to 2019. Pathology regarding the type of dysplasia, medications, and diagnoses that may predispose to immunosuppression were collected.

In all, 810 patients with a mean age of 51.7 (range 20-91) years underwent haemorrhoidectomy. Eighteen (2.2%) of the patients had abnormal pathology (low-grade squamous intraepithelial lesion, 3; high-grade squamous intraepithelial lesion, 12; SCC, 2; adenocarcinoma, 1). Thirty-seven (4.5%) of the entire cohort had some risk factors for immunosuppression: chronic steroid use (nine), human immunodeficiency virus (HIV) (13), biologic medications (six), transplant recipients (two) and immunocompromising diseases (four). Only 4/18 patients had an immunosuppression risk in that all four of these patients were HIV-positive. Surveillance following excision was undertaken for an average of 6 (range 1-12) months, during which time four patients underwent a repeat biopsy.

Anal dysplasia found in an otherwise asymptomatic population has a prevalence of 2.2%. This finding supports the routine examination of benign anorectal specimens undergoing microscopic examination. Interestingly, the majority of the patients identified had no immunosuppressant risk factors.