Anus Flashcards
What is the most common carcinoma of the anus?
Squamous cell carcinoma (80%)
What cell types are found in carcinomas of the anus?
- Squamous cell carcinoma
- Cloacogenic (transitional cell)
- Adenocarcinoma, melanoma, mucoepidermal
What is the incidence of anal carcinoma?
Rare
What is anal Bowen’s disease?
Squamous cell carcinoma in situ
How is anal Bowen’s disease treated?
Local wide excision
What is Paget’s disease of the anus?
Adenocarcinoma in situ of the anus
How is Paget’s disease of the anus treated?
Local wide excision
What are the risk factors for anal cancer?
HPV, condyloma, HSV, HIV, chronic inflammation, immunosuppression, homosexuality in males, cervical or vaginal cancer, STDs, smoking
What is the most common symptom of anal carcinoma?
Anal bleeding
What are the other signs and symptoms of anal carcinoma?
Pain, mass, mucus per rectum, pruritus
What percentage of patients with anal cancer is asymptomatic?
25%
To what locations do anal canal cancers metastasize?
Lymph nodes, liver, bone, lung
What is the lymphatic drainage below the dentate line?
Below to inguinal lymph nodes (above to pelvic chains)
Are most patients with anal cancer diagnosed early or late?
Late
What is the workup of a patient with suspected anal carcinoma?
H&P; DRE; proctoscopic exam; colonoscopy; biopsy; abdominal and pelvic CT; transanal U/S; CXR; LFTs
What is anal margin cancer?
Anal verge out 5 cm onto the perianal skin
What is anal canal cancer?
Proximal to anal verge up to the border of the internal sphincter
How is an anal canal epidermal carcinoma treated?
NIGRO protocol:
- Chemotherapy (5-FU, mitomycin C)
- Radiation
- Post-radiation therapy scar biopsy (6-8 weeks post-XRT)
What percentage of patients with anal canal epidermal carcinoma have a complete response with the NIGRO protocol?
90%
What is the 5-year survival for anal canal epidermal carcinoma with the NIGRO protocol?
85%
What is the treatment for local recurrence of anal cancer after the NIGRO protocol?
May repeat chemotherapy/XRT or salvage APR
How is a small (< 5 cm) anal margin cancer treated?
Surgical excision with 1-cm margins
How is a large (> 5 cm) anal margin cancer treated?
Chemoradiation
What is the treatment of anal melanoma?
Wide excision or APR (especially if tumor is large) +/- XRT, chemotherapy
What is the 5-year survival rate with anal melanoma?
< 10%
How many patients with anal melanoma have an amelanotic anal tumor?
Approximately 33%, thus making diagnosis difficult without pathology
What is fistula in ano?
Anal fistula, from rectum to perianal skin
What are the causes of fistula in ano?
Usually anal crypt/gland infection (usually perianal abscess)
What are the signs and symptoms of fistula in ano?
Perianal drainage, perirectal abscess, recurrent perirectal abscess, “diaper rash”, itching
What disease should be considered with fistula in ano?
Crohn’s disease
How is the diagnosis of fistula in ano made?
Exam, proctoscope
What is Goodsall’s rule?
Fistulas originating anterior to a transverse line through the anus will course straight ahead and exit anteriorly, whereas those exiting posteriorly have a curved tract
What is the management of anorectal fistulas?
- Define the anatomy
- Marsupialization of fistula tract
- Wound care: routine Sitz baths and dressing changes
- Seton placement if fistula is through the sphincter muscle
What is a seton?
Thick suture placed through fistula tract to allow slow transection of sphincter muscle.
Scar tissue formed will hold the sphincter muscle in place and allow for continence after transection
What percentage of patients with a perirectal abscess develop a fistula in ano after drainage?
50%
How do you find the internal rectal opening of an anorectal fistula in the OR?
Inject H2O2 (or methylene blue) in external opening, then look for bubbles (or blue dye) coming out of internal opening
What is a sitz bath?
Sitting in a warm bath (usually done after bowel movement and TID)
What is a perirectal abscess?
Abscess formation around the anus/rectum
What are the signs and symptoms of perirectal abscess?
Rectal pain, drainage of pus, fever, perianal mass
How is the diagnosis of perirectal abscess made?
PE, DRE: perianal/rectal submucosal mass/fluctuance
What is the cause of a perirectal abscess?
Crypt abscess in dentate line with spread
What is the treatment for a perirectal abscess?
Drainage, sitz bath, anal hygiene, stool softeners
What is the indication for postoperative IV antibiotics for drainage of a perirectal abscess?
Cellulitis, immunosuppression, diabetes, heart valve abnormality
What percentage of patients develops a fistula in ano during the 6 months after perirectal abscess surgery?
50%
What is an anal fissure?
Tear or fissure in the anal epithelium
What is the most common site of an anal fissure?
Posterior midline (comparatively low blood flow)
What is the cause of an anal fissure?
Hard stool passage, constipation, hyperactive sphincter, disease process (e.g. Crohn’s disease)
What are the signs and symptoms of an anal fissure?
Pain the anus, painful (can be excruciating) bowel movement, rectal bleeding, blood on toilet tissue after bowel movement, sentinel rage, tear in the anal skin, extremely painful rectal exam, sentinel pile, hypertrophic papilla
What is a sentinel pile?
Thickened mucosa/skin at the distal end of an anal fissure that is often confused with a small hemorrhoid
What is the anal fissure triad for a chronic fissure?
- Fissure
- Sentinel pile
- Hypertrophied anal papilla
What is the conservative treatment for an anal fissure?
Sitz baths, stool softeners, high fiber diet, excellent anal hygiene, topical nifedipine, Botox
What disease processes must be considered with a chronic anal fissure?
Crohn’s disease, anal cancer, STDs, UC, AIDS
What are the indications for surgery for an anal fissure?
Chronic fissure refractory to conservative treatment
What is one surgical option for an anal fissure?
Lateral internal sphincterotomy:
Cut the internal sphincter to release it from spasm
What is the “rule of 90%” for anal fissures?
90% occur posteriorly
90% heal with medical treatment alone
90% of patients who undergo an LIS heal successfully
What are perianal warts?
Warts around the anus/perineum
What is the cause of perianal warts?
Condyloma acuminatum (HPV)
What is the major risk with perianal warts?
Squamous cell carcinoma
What is the treatment if perianal warts are small?
Topical podophyllin, imiquimod
What is the treatment if perianal warts are large?
Surgical resection or laser ablation
What are hemorrhoids?
Engorgement of the venous plexuses of the rectum, anus, or both, with protrusion of the mucosa, anal margin, or both
Why do we have “healthy” hemorrhoidal tissue?
Thought to be involved with fluid/air continence
What are the signs and symptoms of hemorrhoids?
Anal mass/prolapse, bleeding, itching, pain
Which type of hemorrhoids, internal or external, is painful?
External below the dentate line
If a patient has excruciating anal pain and history of hemorrhoids, what is the likely diagnosis?
Thrombosed external hemorrhoid (treat by excision)
What are the causes of hemorrhoids?
Constipation, portal hypertension, pregnancy
What is an internal hemorrhoid?
Hemorrhoid above the dentate line
What is an external hemorrhoid?
Hemorrhoid below the dentate line
What are the 3 hemorrhoid quadrants?
- Left lateral
- Right posterior
- Right anterior
What is a 1st degree internal hemorrhoid?
Hemorrhoid that does not prolapse
What is a 2nd degree internal hemorrhoid?
Prolapses with defecation, but returns on its own
What is a 3rd degree internal hemorrhoid?
Prolapses with defecation or any type of Valsalva maneuver and requires active manual reduction
What is a 4th degree internal hemorrhoid?
Prolapsed hemorrhoid that cannot be reduced
What is the treatment for hemorrhoids?
High-fiber diet, anal hygiene, topic steroids, sits baths, rubber band ligation, surgical resection for large refractory hemorrhoids, infrared coagulation, harmonic scalpel
What is a closed vs. open hemorrhoidectomy?
Closed (Ferguson): closes the mucosa with sutures after hemorrhoid tissue removal.
Open (Milligan-Morgan): leaves mucosa open.
What are the dreaded complications of hemorrhoidectomy?
Exsanguination, pelvic infection, incontinence, anal stricture
What condition is a contraindication for hemorrhoidectomy?
Crohn’s disease
What must be ruled out with lower GI bleeding believed to be caused by hemorrhoids?
Colon cancer