Hemorrhoids

Anus & perianal area

Other nonneoplastic

Hemorrhoids

Topic Completed: 1 May 2014

Minor changes: 16 November 2020

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PubMed Search: Hemorrhoids [title] anus "loattrfree full text"[sb]

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Table of Contents

Cite this page: Weisenberg E. Hemorrhoids. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/anushemorrhoids.html. Accessed March 5th, 2021.

Definition / general

Dilated / ectatic varices of anal and perianal venous plexuses (anal cushions) normally present in submucosa
From Greek "haimorrhoides phlebes" - bleeding veins
Due to possibility of encountering other findings (see below), careful histopathologic evaluation of hemorrhoids is obligatory

Epidemiology

Most literature estimates are 4 - 5% of general population, but many authors believe these numbers grossly underestimate its prevalence
Many sufferers do not seek medical attention
No sexual predominance (except younger, pregnant patients)
More common in whites vs. African Americans
Peak age of diagnosis 45 - 65 years, rare under age 30 except in pregnancy

Sites

Generally located at left lateral, right lateral and right posterior portions of the anal canal (4:00, 7:00, and 11:00 in lithotomy position)
Hemorrhoids proximal to dentate line are known as internal hemorrhoids; distal to dentate line, hemorrhoids are known as external hemorrhoids
Mixed hemorrhoids that cross the dentate line occur

Pathophysiology

Dilated venous plexuses arise from elevated pressure in the hemorrhoidal plexus
Hemorrhoidal cushions are likely normal structures involved in continence, normally dependency will lead to stasis
Elevated intraabdominal pressure leads to vascular dilation and if persistent, may lead to hemorrhoid formation
Degradation of normal supporting structures in the hemorrhoidal plexus also plays a role; older patients appear to be more prone to this
Direct arteriovenous communication with dilation occurs between terminal branches of rectal and hemorrhoidal arteries and veins of the hemorrhoidal plexuses

Etiology

Increased intraabdominal pressure from pregnancy, rectal carcinoma, uterine leiomyomata, other pelvic masses, increased straining at stool often related to low fiber diet, prolonged sitting at stool, persistent diarrhea, ascites
There is controversy whether uncomplicated portal hypertension leads to hemorrhoids
Prolapsed hemorrhoids are prone to thrombosis and ulceration with accompanying inflammation
Thrombosed vessels undergo recanalization

Clinical features

Patients usually have painless bleeding, noticing blood in the toilet or on lavatory paper
Patients may experience pain or discomfort, especially with thrombosis, strangulation or ulceration
Anemia from hemorrhoids is unusual - patients should undergo hematologic evaluation
There is controversy concerning the mechanisms involved in serious hemorrhoidal bleeding in cirrhotics: excessive bleeding may be solely from coagulopathy or portal hypertension may be an important cause
Clinically four grades:
- First degree, anal cushions that slide down past dentate line with straining at stool, that bleed with defecation
- Second, anal cushions that prolapse with straining, but reduce spontaneously
- Third, hemorrhoids that remain outside of the anal canal unless manually replaced
- Fourth, hemorrhoids that cannot be reduced

Diagnosis

Usually a clinical diagnosis; hypertrophied anal papillae may have similar appearance

Prognostic factors

Hemorrhoids are annoying, but significant morbidity is rare unless secondary to complications of therapy
Potential complications include pain, urinary retention, constipation, fistula, prolapse, incontinence

Treatment

Medical intervention may include high fiber diet with stool softeners, topical analgesics, Sitz baths, bulk laxatives
Other interventions include rubber band ligation, sclerotherapy or cryotherapy, infrared coagulation or hemorrhoidectomy

Clinical images

Images hosted on other servers:

Prominent prolapsed true (internal) hemorrhoids

Hemorrhoids at anorectal junction (scroll down)

Microscopic (histologic) description

Dilated, thick walled, congested submucosal vessels and sinusoidal spaces, often with thrombosis; variable hemorrhage into connective tissue
Dilated spaces may show exuberant vascular proliferation confined to vessel known as papillary endothelial hyperplasia
Internal hemorrhoids are lined by rectal or transitional mucosa, external hemorrhoids have a squamous lining
Surface may show ulceration
Pale cells in epidermis resembling Paget cells (pagetoid dyskeratosis) in 68%, prominent in 22%, likely related to trauma related to prolapse (Arch Pathol Lab Med 2001;125:1058)
Examination of hemorrhoids may reveal low or high grade squamous intraepithelial lesions, invasive squamous cell carcinoma, rectal carcinoma, neuroendocrine tumors, melanoma, lymphoma, inflammatory bowel disease, nonspecific granulomas, Herpes Simplex Virus infection, syphilis

Microscopic (histologic) images

Contributed by Dr. Elliot Weisenberg

Dilated, thick walled, congested submucosal vessels

Differential diagnosis

Diagnosis usually straightforward, but associated findings may be important (see above)
Pagetoid dyskeratosis may be confused with Paget's disease
Papillary endothelial hyperplasia in recanalizing hemorrhoids may resemble vascular tumors, but is confined to vascular space

Additional references