Step 2 CK · Surgery

Anal Fissure, Pilonidal Disease & Anal Cancer

Name: Anal Fissure, Pilonidal Disease & Anal Cancer
Creator: Veli Bakalov, MD

Tearing pain, a draining cleft, and the 'hemorrhoid' that was cancer

Surgery·General Surgery·5 min read·9 high-yield points·Reviewed by Veli Bakalov, MD @HemeOncBuddy

Study materialsNo account needed

Card deckActive-recall cards · quick checks · quiz

High-yield

Anal fissure causes tearing pain and bright-red blood with defecation; about 90% sit in the posterior midline, kept open by internal sphincter spasm and poor perfusion.
Lateral, multiple, or painless fissures are atypical: examine under anesthesia and biopsy for Crohn disease, HIV, TB, syphilis, or cancer.
Fissure ladder: fiber and sitz baths → topical nitroglycerin or diltiazem → botulinum toxin → lateral internal sphincterotomy (never posterior).
Avoid topical nitroglycerin in patients taking PDE-5 inhibitors; diltiazem heals as well with fewer headaches.
Pilonidal abscess → incision and drainage off the midline; chronic sinus → excision with open healing or off-midline flap, plus hair removal.
Anal SCC is driven by HPV 16/18 and is most common with HIV and receptive anal intercourse; high-risk groups get anal cytology and high-resolution anoscopy.
Anal cancer: biopsy and inguinal node exam, then Nigro chemoradiation (5-FU + mitomycin); abdominoperineal resection only for persistent or recurrent disease.
Concentric rings mean full-thickness rectal prolapse (rectopexy if fit, perineal repair if frail); radial folds mean prolapsed hemorrhoids.
Pruritus ani is usually hygiene-related; biopsy a refractory perianal plaque to exclude Paget or Bowen disease.

Anal fissure: recognition

What it is. A linear tear in the anoderm below the dentate line, where somatic innervation makes it exquisitely painful. About 90% lie in the posterior midline; anterior midline fissures are more common in women after childbirth. Sharp, tearing pain during and after defecation, sometimes lasting hours, comes with bright-red blood on the toilet paper.

Why it persists. Hard stool starts the tear; pain triggers internal sphincter spasm, and the high resting pressure reduces flow to the poorly perfused posterior midline, so the ischemic tear fails to heal and pain sustains the spasm. Therapy aims to soften stool and relax the sphincter. Gently parting the buttocks usually shows the fissure; a painful digital exam can wait.

Types of anal fissure

Feature	Acute	Chronic	Atypical
Location	Posterior (or anterior) midline	Posterior (or anterior) midline	Lateral or multiple
Appearance	<6–8 weeks; clean, superficial tear	>6–8 weeks; raised edges, exposed internal sphincter fibers, sentinel tag, hypertrophied papilla	Large, deep, painless, or nonhealing
Cause	Hard stool, childbirth	Persistent spasm and ischemia	Crohn disease, HIV, tuberculosis, syphilis, anal cancer
Next step	Fiber, fluids, sitz baths	Sphincter relaxation (below)	Examination under anesthesia with biopsy and cultures; HIV and syphilis tests; colonoscopy if Crohn is suspected

A sentinel skin tag is easily mistaken for an external hemorrhoid; look just inside it for the fissure.

Treating fissures

Conservative carePsyllium fiber, fluids, warm sitz baths, topical lidocaine; most acute fissures heal
Topical sphincter relaxant, 6–8 weeksNitroglycerin ointment (nitric oxide donor) or diltiazem/nifedipine ointment, which heals as well with fewer headaches
Botulinum toxinInjected into the internal sphincter as a temporary chemical sphincterotomy
Lateral internal sphincterotomyThe most effective option, healing more than 90% of chronic fissures

Limits. Headache is the main reason patients stop nitroglycerin, and nitrates must not be combined with PDE-5 inhibitors. Sphincterotomy carries a small risk of incontinence to flatus or minor soiling, so it is avoided when continence is already fragile (an anal advancement flap is an alternative). Manual anal dilation has been abandoned because of incontinence.

Never divide the sphincter in the posterior midline (keyhole deformity with soiling), and do not perform sphincterotomy for Crohn-related fissures.

Pilonidal disease

Pathogenesis. Shed hair is driven into the skin of the deep natal cleft, creating midline pits, a foreign-body sinus, and recurrent sacrococcygeal abscesses. Typical patients are young, hirsute, often overweight men who sit for long periods, hence the nickname "jeep disease."

Acute abscess. Incision and drainage through an incision placed off the midline, because midline wounds in the cleft heal poorly; antibiotics are added only for cellulitis or immunosuppression.

Chronic or recurrent sinus. The pits and tracts are excised. An open wound recurs less but heals slowly; primary midline closure fails often, so off-midline closures and flaps (cleft lift, Karydakis, Limberg) are preferred. Shaving or laser hair removal reduces recurrence.

Anal cancer

Risk and screening. Most anal cancers are squamous cell carcinomas caused by HPV, chiefly type 16 and also 18, through high-grade squamous intraepithelial lesions (HSIL). Risk is highest with HIV, especially in men who have sex with men, and is raised by receptive anal intercourse, prior cervical or vulvar HSIL or cancer, transplant immunosuppression, and smoking. High-risk groups are screened with anal cytology (± HPV testing), starting at age 35 for men who have sex with men and transgender women with HIV and at 45 for other people with HIV (IANS 2024); abnormal results lead to high-resolution anoscopy with biopsy. Treating HSIL in people with HIV lowered progression to cancer in the ANCHOR trial, and HPV vaccination prevents HSIL.

Diagnosis. Bleeding is the most common symptom and is often blamed on hemorrhoids; pain, a mass, pruritus, and discharge also occur. Examine with DRE and anoscopy, biopsy any suspicious lesion, and palpate the inguinal nodes (FNA if enlarged), since the canal below the dentate line drains to superficial inguinal nodes (above it, to perirectal and internal iliac nodes). Stage with CT of the chest, abdomen, and pelvis or PET-CT plus pelvic MRI, and test for HIV.

Treatment. Definitive chemoradiation with 5-FU (or capecitabine) and mitomycin C, the Nigro protocol, is first-line for nonmetastatic anal canal SCC, including node-positive disease, and preserves the sphincter in most patients. Tumors keep shrinking for months, so response is judged up to about 26 weeks. Biopsy-proven persistent or recurrent local disease is salvaged with abdominoperineal resection and permanent colostomy; small, well-differentiated perianal tumors may be locally excised.

Rectal prolapse and pruritus ani

Protruding anal mass

Feature	Full-thickness rectal prolapse	Prolapsed internal hemorrhoids
Folds	Concentric circular rings	Radial grooves between cushions
Typical patient	Elderly multiparous women with chronic straining; children with cystic fibrosis	Adults with constipation or pregnancy
Symptoms	Mucus discharge, fecal incontinence	Painless bright-red bleeding
Treatment	Rectopexy or perineal repair	Banding or excisional hemorrhoidectomy

Rectal prolapse. Have the patient strain on a commode if nothing is visible, and perform colonoscopy to exclude a neoplastic lead point. Fit patients get abdominal, usually laparoscopic, rectopexy, with sigmoid resection added when constipation dominates. Frail patients get a perineal operation (Altemeier rectosigmoidectomy or Delorme repair), which is better tolerated but recurs more often. A child with prolapse needs a sweat chloride test.

Pruritus ani. Usually idiopathic, driven by moisture, fecal soiling, irritant soaps and wipes, dietary triggers such as coffee, citrus, and spicy food, and the itch-scratch cycle. Secondary causes include hemorrhoids, fissures, pinworms, Candida, contact dermatitis, psoriasis, and neoplasia. Treatment is gentle water cleansing, drying, a barrier cream, fiber, avoiding triggers, and a brief course of low-potency hydrocortisone. A persistent eczematous plaque is biopsied to exclude extramammary Paget disease or Bowen disease.