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| Squamous Carcinoma of Anus | ||
| Etiology •Squamous carcinoma of the anus has been associated with a variety of sexually transmitted diseases including: HPV, Lymphogranuloma venereum, Herpes simplex, Chlamydia and Gonorrhea. •Many cases do not have evidence of a sexually transmitted disease and the etiology in these cases is unknown. | ||
| Pathogenesis •Development of carcinoma in HPV+ patients has been linked to the development of anal condyloma and intraepithelial dysplasia associated with HPV 16 and 18, similar to the develoment of cervical neoplasia in HPV+ patients. •The mode of pathogenesis in HPV- patients is unknown., | ||
| Epidemiology •Squamous carcinoma of the anus is most common during the 5th and 6th decades. •Females are affected 2-3X more than males and whites more than blacks. •Single males have a six-fold higher incidence than married males, and this appears due to the high prevalence of HPV infection associated with anal intercourse. •There is a recent significant rise in the incidence of anal squamous carcinoma associated with the rise in HPV infection. •An increased incidence has also been noted in renal transplant patients with immunosuppression. | ||
| General Gross Description •The tumors present as mass lesions which are exophytic with a smooth surface which may be ulcerated in larger lesions. •They are present above and below the Dentate Line. •Cut surface is firm and white. •Some tumors may show evidence of contiguous condyloma in the HPV+ patients. •Examples: | ||
| General Microscopic Description •The microscopic appearance is variable as several variants exist. •Most commonly their appearance is similar to non-keratinizing cervical squamous carcinoma. •The most commonly seen variants demonstrate basaloid, adenoid cystic or transitional (cloacogenic) patterns. •Examples: | ||
| Clinical Correlation •The two most common symptoms are anal bleeding (50%) and pain (30%). •Regardless of histologic variant, squamous carcinomas of the anus show similar behavior with direct extension into the sphincter, vagina, perianal tissue and prostate. •Lymphangitic spread through the perirectal and groin nodes are both seen. •Primary treatment is surgical with local resection limited to Stage 1 and small Stage 2 lesions. Abdominal-perineal resection is no longer in favor. •More advanced lesions or larger lesions are treated with radiation therapy often combined with chemotherapy. •Prognosis is determined by site (above or below the dentate line), Size (Tumors <2cm are more favorable), and degree of cellular differentiation. •Overall survival at 5yrs is greater than 70%. | ||
| References Grastrointestinal Pathology, Fenoglio-Preiser CM et al, New York: Raven Press 1989, pp. 826-32. Please be patient during transfer. Medline will open in a new window. To return, close the Medline Window Squamous Carcinoma of Anus
| Synopsis by: Martin Nadel M.D. (T69000M80703)[335]
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