![special screening for malignant neoplasmms of colol special screening for malignant neoplasmms of colol](https://media.springernature.com/original/springer-static/image/chp:10.1007%2F978-3-642-13327-5_158/MediaObjects/978-3-642-13327-5_158_Fig6_HTML.jpg)
Vimentin is ubiquitously expressed by melanoma and is often expressed by lymphomas. Promise us that you will never order a vimentin immunostain! This wastes both limited tissue and money in small biopsies and money when dealing with large samples. *MMR, mismatch repair protein immunohistochemistry Table 1 lists these broad tumor classes with associated screening markers. Before signing a case out as “undifferentiated malignant neoplasm,” consider the possibility of germ cell tumor-which is eminently treatable. 2 Most clinically significant mesenchymal tumors involving the GI tract are gastrointestinal stromal tumors (GIST). Carcinomas outnumber lymphomas and melanomas on the order of 15:2:1. Consider the likely diagnostic possibilities based on the anatomic site, patient demographics and key morphologic features on H&E, and then choose testing with a specific plan for how to interpret both positive and negative results and a plan for additional testing guided by the information from the initial tests.Īs daunted as you may be by the poorly to undifferentiated malignant neoplasm staring back at you, there is a relatively limited differential diagnosis. A “shotgun” approach must be avoided, as it runs the risk of depleting precious tissue and incurs unnecessary expense. This may require more than one “round” of ancillary studies, in which the first set of testing is used to classify the neoplasm into a general category-followed by more specific testing. Since mucosal biopsies harboring poorly differentiated malignant neoplasms are by their very nature quite small, the guiding principle is to exploit ancillary studies (usually immunohistochemistry) in a curated fashion, directed at a very specific differential diagnosis.
![special screening for malignant neoplasmms of colol special screening for malignant neoplasmms of colol](http://www.research.olemiss.edu/UMQuest/2007/Winter/images/RighteousGentilesCover.jpg)
General comments on evaluation of limited samples