Research
Print page Print page
Switch language
Rigshospitalet - a part of Copenhagen University Hospital
Published

Medullary carcinoma of the colon: can the undifferentiated be differentiated?

Research output: Contribution to journalJournal articleResearchpeer-review

  1. Methodological approach to Microscopic Colitis diagnosis

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. Lymphomas of the head and neck region: an update

    Research output: Contribution to journalReviewResearchpeer-review

  3. Prognostic significance of 1p36 locus deletion in adenoid cystic carcinoma of the salivary glands

    Research output: Contribution to journalJournal articleResearchpeer-review

  1. The molecular profile of mucosal melanoma

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. A rare missense variant in APC interrupts splicing and causes AFAP in two Danish families

    Research output: Contribution to journalJournal articleResearchpeer-review

View graph of relations

Medullary carcinoma of the colon is a rare variant of colorectal cancer claimed to have a more favorable prognosis than conventional adenocarcinomas. The histopathologic appearance may be difficult to distinguish from poorly differentiated adenocarcinoma. The study aimed to evaluate the diagnostic interobserver agreement and to characterize the immunohistochemical and molecular differences between these two subgroups. Fifteen cases initially classified as medullary carcinoma and 30 cases of poorly differentiated adenocarcinomas were included. Two pathologists reviewed the slides independently without knowledge of the original diagnosis and subgrouped the tumors into the two entities. Agreement was reached in 31 of 45 cases (69 %) with kappa = 0.32. An extensive immunohistochemical panel was performed, and KRAS, NRAS, and BRAF mutational status was assessed. Of the 31 cases with diagnostic agreement, the expression of only MLH-1 along with corresponding expression of PMS-2 differed significantly (p = 0.04). A high rate of BRAF mutations was detected in both subgroups without significant differences. Expression of MLH-1 was superior in dividing the tumors into two separate entities with significant differences in CK20 (p = 0.005) expression and in the rate of BRAF mutations (p = 0.0035). In conclusion, medullary carcinomas of the colon are difficult to discriminate from poorly differentiated adenocarcinoma even with the help of immunohistochemical and molecular analyses. This raises the question whether these morphological subtypes should be maintained or whether an alternative classification of poorly differentiated colorectal adenocarcinomas based on MLH-1 status rather than morphology should be suggested.

Original languageEnglish
JournalVirchows Archiv : an international journal of pathology
Volume466
Issue number1
Pages (from-to)13-20
Number of pages8
ISSN0945-6317
DOIs
Publication statusPublished - Jan 2015

ID: 44963525