Melanosis Coli
Sharon K. Bihlmeyer, MD
Key Facts
Terminology
Presence of melanin-like pigment in intestinal mucosa
Etiology/Pathogenesis
Close association with anthraquinone drugs including cascara sagrada, aloe, rhubarb, senna, and frangula
Pigment deposition secondary to increased apoptosis of many possible causes
Clinical Issues
Seen macroscopically in 0.5-5.3% of autopsies, but microscopically in 59.9%
Microscopic Pathology
Macrophages, singly and in small collections, contain brown-black globular pigment within lamina propria
PAS(+)
 Hematoxylin & eosin shows a low-power image of a colon biopsy specimen with pigment-laden macrophages within the lamina propria  . |
 Light microscopy shows a higher-power view of lamina propria containing macrophages with brown pigment of melanosis  . |
TERMINOLOGY
Synonyms
Lipofuscinosis coli
Pseudomelanosis coli
Definitions
Presence of melanin-like pigment in intestinal mucosa
Autofluorescent pigment containing melanin and glycoconjugates
Preferred name is “melanized ceroid”
ETIOLOGY/PATHOGENESIS
Environmental Exposure
Close association with anthraquinone drugs
Cascara sagrada
Aloe
Rhubarb
Senna
Frangula
Pigment derived from apoptotic epithelial cells (ceroid component) and anthranoids (melanic substance)
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