COLORECTAL SURGERY BLOG

The term Anal Intraepithelial Neoplasia (AIN) describes the microscopic finding of dysplastic, non-malignant cells in the anal canal. AIN has been subdivided into AIN I, II, and III, representing low, moderate, and high-grade dysplasia. This dysplasia has been thought to arise as a result of local infection with the Human papillomavirus. The Human papillomavirus is a small double-stranded DNA virus with a diameter of 55 nm. and is encased in a protein capsid. The term AIN has gradually replaced other descriptive terminology such as atypical squamous cells of indeterminate significance (ASCUS), low-grade squamous intraepithelial lesions (LSIL), or high-grade squamous intraepithelial lesions (HSIL).

Pilonidal disease represents several forms of a single abnormality. Pilonidal disease may consist of nothing more than asymptomatic midline skin pits overlying the sacrococcygeal area. At the other extreme, the disease may be a large complex abscess associated with sepsis. In between these extremes are sinuses which occasionally cause discomfort and erythema, or sinuses which periodically drain and then return to an asymptomatic state.

Alert to the genetics and findings in patients with hereditary colorectal cancer syndromes, physicians may be better able to diagnose and recommend treatment for the colonic manifestations of each disease.

With a myriad of vexing abbreviations and obscure terminology, the genetics controlling the formation of colonic polyps and malignancies may be difficult to appreciate. A review of these colonic disorders will aid in an understanding of the underlying genetics.

Approximately five per cent of patients with colorectal cancer have an inherited or hereditary mutation in the APC gene, a gene known to be associated with cancer development. Many of the high-risk mutations which lead to colorectal cancer can be located on individual genes using genetic sequence testing. At present however, clinical genetic manipulation cannot reduce the risk of disease development in individual patents.

Hemorrhoidal disease is a considerable source of morbidity, affecting twenty million adults per year. Symptoms can be debilitating and costly when measured in time away from productive activities. In 1980, during game two of the World Series between the Kansas City Royals and the Philadelphia Phillies, George Brett was forced to leave the game in the sixth inning due to hemorrhoidal symptoms. After a minor surgical procedure, he returned for game three and hit a first inning home run blast in the Royals 4 to 3 win. He quipped “…my problems are all behind me…” The Royals lost the series and Brett underwent a hemorrhoidectomy in the off season.

Hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome accounts for four percent of all colorectal cancers. HNPCC is usually the result of an inherited mutation in one of the group of genes known as mismatch repair genes (MMR). This mutation has also been known to arise spontaneously. MMR genes correct errors that result from faulty DNA replication. Colorectal cancer occurring in the absence of polyps or polyposis is the final phenotypic expression of this DNA mutation, although an occult polyp remains the precursor lesion of the cancer.

Anal itching. Pruritus ani. At one time or another, everyone has experienced this unpleasant sensation. Most often, the delightful scratching of the itch relieves the discomfort and puts a stop to the maddening sensation. Not uncommonly however, the itch occurs at an inconvenient moment, in public, during an intimate social situation or at a time when scratching is not possible without looking a bit ridiculous. Worse, the itching may become chronic, with the need to scratch becoming a constant annoyance, bordering on pain.

Anal fissures are a common problem, bringing many patients to the colorectal surgeons’ office with complaints of anal pain. Most patients report feeling a tear, or a splitting sensation at the anus after a normal bowel movement, a bout of diarrhea, or after a particularly hard or large stool.

Squamous cell carcinoma of the anus is the most well known member of an uncommon group of GI neoplasms. The incidence of this tumor has been increasing slowly, with 3,500 cases reported in the United States in 2001, and 5,260 cases reported in 2009.