Hemorrhoids
Julianne K. Purdy, MD
Key Facts
Terminology
Hemorrhoids are normal submucosal vascular beds
Hemorrhoidal disease when vessels dilate and symptoms develop
Clinical Issues
Internal hemorrhoids: Painless rectal bleeding
External hemorrhoids asymptomatic unless acute thrombosis
Microscopic Pathology
Dilated thick- and thin-walled submucosal vessels, thrombosis
Overlying mucosa may be ulcerated & inflamed
Fibromuscular proliferation in lamina propria, thickening of muscularis mucosae
Top Differential Diagnoses
Mucosal prolapse syndrome
 Hematoxylin & eosin shows dilated submucosal vessels beneath squamous epithelium. |
 Hematoxylin & eosin shows a recanalizing thrombus  within a dilated vessel beneath the mucosa of the anorectal junction. |
TERMINOLOGY
Synonyms
Piles
Definitions
Normal submucosal vascular beds with smooth muscle and connective tissue (anal cushions) above and below dentate line
When vessels dilate and symptoms develop → hemorrhoidal disease
ETIOLOGY/PATHOGENESIS
Theories
Connective tissue and smooth muscle that anchor vascular cushions to sphincter deteriorate with age
→ displacement into anal canal and engorgement of vessels
Fecal bolus forces vascular plexus against hypertrophied anal sphincter
→ enlargement of vessels, symptoms
Vascular cushions similar to erectile tissue: Symptoms from swelling of cushions
Possible Contributing Factors
Pregnancy, inadequate fiber intake, chronic constipation, prolonged sitting and straining, chronic diarrhea
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