disease of anorectal region Flashcards
What is a pilonidal sinus, and what are its characteristic features?
A pilonidal sinus is a common condition typically affecting the region of the base of the spine or the intergluteal cleft. It is caused by follicular occlusion, leading to the formation of a sinus or cyst in the crease between the buttocks. Characteristic features include dense inflammatory reaction, erosion, and ulceration of the overlying epidermis. Free hair shafts are often seen coursing through the inflammatory focus.
Describe the pathogenesis and clinical features of mucosal prolapsed syndrome (solitary rectal ulcer syndrome).
-Mucosal prolapsed syndrome is characterized by abnormal function of anal and pelvic floor musculature during defecation, leading to rectal mucosal prolapse or intussusception.
-It is associated with histologic changes of sessile serrated polyps and presents with constipation, blood and mucus from the rectum, changes in bowel habits, and pain.
-Histological findings include well-demarcated irregular ulcers, polypoid lesions, and mucosal thickening.
What is an anal fissure, and what are its common causes?
-An anal fissure is a painful linear separation or tear of the anal canal mucosa distal to the dentate line.
-Trauma due to constipation, instrumentation, childbirth, or sexual abuse is a common cause.
- Nontraumatic cases may result from infections, inflammatory bowel disease, or malignancy involving the anal mucosa.
Explain the etiology and classification of anal fistulas.
-Anal fistulas are abnormal fistulous communications that usually open within the anal canal and may extend to the skin or perianal soft tissue.
-Etiologies include Crohn’s disease, infections (such as tuberculosis and lymphogranuloma venereum), and rectal foreign bodies.
-They are classified based on their anatomical location, including low fistulas, intersphincteric fistulas, trans-sphincteric fistulas, and supersphincteric fistulas.
What are hemorrhoids, and what predisposes individuals to their development?
Hemorrhoids are dilated or ectatic varices of the anal and perianal venous plexuses.
-Predisposing factors include constipation with straining during defecation and pregnancy. Persistently elevated venous pressure in the hemorrhoidal plexus and congested collateral circulation due to portal hypertension contribute to their pathogenesis.
Describe the characteristics and transmission of condyloma acuminatum.
Condyloma acuminatum is a verrucous lesion associated with human papillomavirus (HPV) infection, particularly types 6, 11, and 16.
-Lesions related to HPV 16 are associated with the development of squamous cell carcinoma.
- Transmission occurs through sexual contact, primarily as a sexually transmitted infection.
-Microscopic features include papillomatous epidermal hyperplasia and vacuolated keratinocytes with shrunken nuclei (koilocytes).
What are the types of malignant neoplasms of the anus, and what are their associations?
Malignant neoplasms of the anus include squamous cell carcinoma, adenocarcinoma, and basaloid carcinoma (basal cell carcinoma).
-Squamous cell carcinoma is associated with condyloma acuminatum, while adenocarcinoma may extend from rectal carcinoma.
-Basaloid carcinoma arises from the basal layer of the surface stratified squamous epithelium.
What is the pathogenesis of pilonidal sinus, and why is the term “pilonidal” used to describe this condition?
The pathogenesis of pilonidal sinus involves follicular occlusion, leading to the formation of a sinus or cyst in the crease between the buttocks.
The term “pilonidal” is used because the sinus or cyst is typically located in the pilonidal or natal cleft, where hair may accumulate and form a nest-like structure.
Describe the microscopic findings associated with anal fissures.
Microscopic findings in anal fissures include ulcerated transitional or columnar mucosa with acute and chronic inflammation, granulation tissue, and reactive and regenerative epithelial changes or foreign body giant cell reaction.
What are the common complications of anal fistulas, and what factors contribute to their development?
Common complications of anal fistulas include anal canal adenocarcinoma. Factors contributing to their development include underlying conditions such as Crohn’s disease, infections (such as tuberculosis and lymphogranuloma venereum), and rectal foreign bodies.
Discuss the clinical features and histological changes seen in hemorrhoids.
Hemorrhoids present with clinical features such as mass per rectum, bleeding, and pain associated with fissure, thrombosis, or strangulation.
Histologically, they are characterized by thin-walled, dilated, and congested submucosal veins that protrude below the squamous epithelium of the anus or rectal mucosa. Secondary changes may include thrombosis and neovascularization.
Explain the association between condyloma acuminatum and human papillomavirus (HPV) infection.
Condyloma acuminatum is associated with HPV infection, particularly types 6, 11, and 16. HPV 16-related lesions are associated with the development of squamous cell carcinoma. Transmission occurs through sexual contact, primarily as a sexually transmitted infection.
What are the types of malignant neoplasms of the anus, and how do they arise?
Malignant neoplasms of the anus include squamous cell carcinoma, adenocarcinoma, and basaloid carcinoma (basal cell carcinoma). Squamous cell carcinoma is associated with condyloma acuminatum, while adenocarcinoma may extend from rectal carcinoma. Basaloid carcinoma arises from the basal layer of the surface stratified squamous epithelium.
