Home   Chapter Home   Jobs   Conferences   Fellowships   Books


Colon tumor


Medullary carcinoma

Reviewers: Charanjeet Singh, M.D. (see Reviewers page)
Revised: 13 February 2014, last major update September 2011
Copyright: (c) 2003-2014, PathologyOutlines.com, Inc.

Clinical features

● Also called undifferentiated carcinoma; a subtype of poorly differentiated adenocarcinoma
● <1% of colorectal neoplasms
● Often elderly women, right sided tumors
● Strongly associated with high degree of microsatellite instability (MSI), indicative of loss of normal DNA repair gene function
● Often better clinical outcome independent of stage than microsatellite stable tumors or tumors with low levels of microsatellite instability; usually no/few nodal metastases
● May be more sensitive to 5 FU chemotherapy
● May have more metachronous colonic carcinomas

Case reports

● 79 year old woman with ulcerated cecal tumor (Arch Pathol Lab Med 2005;129:113)

Gross description

● Large with invasion into adjacent organs

Micro description

● Expansive growth pattern of well circumscribed sheets of tumor cells
● Also nested, organoid or trabecular patterns, but no/minimal mucin production and no tubule formation
● Pushing border with prominent lymphocytic infiltration
● Cells are uniform, polygonal to round, small to medium sized with variable eosinophilic cytoplasm and small/medium nuclei with open chromatin and prominent nucleoli, frequent mitotic activity
● Neuroendocrine features but negative for neuroendocrine markers

Micro images

Figure 1-tar black tumor with ulceration, 2-sheets of tumor cells with extensive necrosis, 3-cells have prominent nucleoli, 4-CK+

Loss of MSH2 expression; Medullary carcinoma (fig A) compared to poorly differentiated colon carcinoma (fig B)

Comparison of calretinin, CDX2 and MLH1 staining in medullary and poorly differentiated colon adenocarcinoma


High grade tumor cells in syncytial pattern

MUC staining of medullary colon carcinoma

Positive stains

● Keratin, CEA, EMA, Calretinin

Negative stains

● Neuroendocrine markers, MLH1 and MSH2 (Mod Pathol 2002;15:741), p53
● CDX2 (positive in only 19%, Hum Pathol 2009;40:398)

Flow cytometry

● Diploid

Differential diagnosis

Lymphoepithelioma-like carcinoma

Additional references

Am J Clin Pathol 2005;123:56, Hum Pathol 1999;30:843, Int J Oncol 2010;37:901

End of Colon tumor > Carcinoma > Medullary carcinoma

This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

All information on this website is protected by copyright of PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions (click here for other contact information).