methylene blue injection
Friday 15 February 2013
It is pathologists’ obligation to retrieve as many lymph nodes as possible from surgical specimens. The vast majority of pathologists follow the guidelines of a minimum of 12 nodes.
Extra efforts will be made if <12 nodes are retrieved, although this will increase the turnaround time for pathology reports. The extra efforts may include repeated manual searches, submitting more sections, utilizing fat clearance techniques, or ex vivo injection of methylene blue.
The application of fat clearance techniques has several potential disadvantages, such as further delay in signout of the pathology reports, cost, toxicity and disposal of clearing solutions, and unknown effect on immunohistochemistry. As a result, fat clearance has not become a standard practice in pathology laboratories.
Methylene blue injection is a relatively new method for colorectal cancer. There have been only a few publications in this area, mostly from the same study group. Its clinical application needs further investigation.
It should be realized that the total number of nodes retrieved is not only dissector-dependent, but also influenced by a number of specimen and patient variables.