Undifferentiated Carcinoma of the Colon and Rectum
Definition
- Undifferentiated carcinoma not otherwise specified, arising in the colon or rectum
Note:
- Medullary carcinoma is covered separately
- Poorly differentiated endocrine (small cell undifferentiated) carcinoma is covered separately
Diagnostic Criteria
- No gland formation (<5% by definition)
- Solid sheets, nests and trabeculae
- Pleomorphic large cells
- Nuclei variable, may be vesicular
- Nucleoli variable
- High nuclear/cytoplasmic ratio
- Scant to moderate cytoplasm
- Infiltrative border
- No intracytoplasmic mucin or expression of chromogranin or synaptophysin
- Generally poor prognosis
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/updates : 1/31/10, 11/12/11
