colorectal medullary carcinoma
Friday 15 February 2013
Definition: Colorectal medullary carcinoma is extremely rare, constituting approximately 5-8 cases for every 10,000 colorectal cancers diagnosed, with a mean annual incidence of 3.47 (±0.75) per 10 million population.
This tumor is characterized by sheets of epithelioid neoplastic cells with large vesicular nuclei, prominent nucleoli, and abundant cytoplasm.
It typically has a pushing border on resection specimens, and is characteristically associated with marked tumorinfiltrating lymphocytes.
Medullary carcinoma is a distinctive histologic subtype that is strongly associated with MSI-H.
It usually has a favorable prognosis despite its poorly differentiated or undifferentiated histology.