Colon tumor
Mesenchymal tumors
Kaposi sarcoma

Author: Raul S. Gonzalez, M.D. (see Authors page)

Revised: 14 February 2017, last major update February 2017

Copyright: (c) 2003-2017,, Inc.

PubMed Search: Kaposi sarcoma colon

Cite this page: Kaposi sarcoma. website. Accessed November 15th, 2018.
Definition / general
  • Vascular malignancy caused by human herpes virus 8 (see topic in Soft tissue chapter)
Essential features
  • Vascular malignancy most often seen in AIDS patients with HHV8 infection
  • Rare in gastrointestinal tract
  • Most common gastrointestinal malignancy attributable to AIDS (Am J Gastroenterol 1991;86:715)
  • Currently rare; incidence decreased from use of HAART for AIDS treatment
  • HHV8 infection
Clinical features
Prognostic factors
Case reports
  • Chemotherapy and radiation preferred over surgery
Clinical images

Images hosted on other servers:

Kaposi sarcoma

Cherry red polyps on endoscopy

Gross description
  • Reddish brown to purple macules or polyps, typically 0.5 - 1.5 cm
Microscopic (histologic) description
  • Lamina propria based lesion composed of spindle cells with mild to moderate atypia, arranged in vague fascicles and separated by slit-like vessels
  • Extravasated red blood cells common
  • PAS positive, diastase resistant hyaline globules sometimes seen
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Dr. Raul Gonzalez, University of Rochester Medical Center (USA):

H&E, intermediate power

H&E, high power

Images hosted on other servers:

Low power

High power


Positive stains
Negative stains
Differential diagnosis