Stanford School of Medicine

Surgical Pathology Criteria

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Adenosquamous Carcinoma of the Colon and Rectum


  • Carcinoma with malignant components exhibiting both glandular and squamous differentiation, arising in the colon and rectum

Covered separately

Diagnostic Criteria

  • Must have a component of usual gland forming colorectal adenocarcinoma
  • Must have a component of squamous carcinoma
    • Must be more than occasional small foci
  • Mixture may be intermingled or discrete foci
  • Must not involve anal squamous mucosa
    • Some require location >5-7 cm above dentate line
    • Anal squamous carcinomas frequently extend into the rectum
  • May be associated with inflammatory intestinal disorders
  • Robert V Rouse MD
    Department of Pathology
    Stanford University School of Medicine
    Stanford CA 94305-5342

    Original posting : 1/31/10, 11/12/11

Differential Diagnosis

  Colorectal Squamous Carcinoma Colorectal Adenosquamous Carcinoma Colorectal Adenocarcinoma with Squamous Metaplasia
Squamous component Malignant Malignant Benign
Glandular component Absent Malignant Malignant
Both components must be more than focal


  • Frequently presents at high stage
  • Historically poor prognosis with surgical treatment
    • Especially for cases presenting at high stage

Grading / Staging


  • Bosman FT, Carneiro F, Hruban RH, Thiese ND (Eds). WHO Classifiication of Tumors of the Digestive System, IARC, Lyon 2010
  • Frizelle FA, Hobday KS, Batts KP, Nelson H. Adenosquamous and squamous carcinoma of the colon and upper rectum: a clinical and histopathologic study. Dis Colon Rectum. 2001 Mar;44(3):341-6.
  • Yokoi K, Tanaka N, Furukawa K, Seya T, Ohaki Y, Tajiri T. Case of adenosquamous carcinoma of the ascending colon. J Nippon Med Sch. 2008 Aug;75(4):242-6.
  • Petrelli NJ, Valle AA, Weber TK, Rodriguez-Bigas M. Adenosquamous carcinoma of the colon and rectum. Dis Colon Rectum. 1996 Nov;39(11):1265-8.
  • Cagir B, Nagy MW, Topham A, Rakinic J, Fry RD. Adenosquamous carcinoma of the colon, rectum, and anus: epidemiology, distribution, and survival characteristics. Dis Colon Rectum. 1999 Feb;42(2):258-63.
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