GEWF colon CA lymph node fixative

A lot of us on the Pathology (PATHO-L) and Histology (HistoNet) listservers 
use special fixatives to facilitate retrieval of lymph nodes from colorectal 
cancer specimens. A group from the University of Western Ontario (at London) 
has an interesting method I'd like to try out. What's different about this 
technique from others I've seen is the use of the special fixative as a 
postfixative after overnight formalin fixation, a real convenience if you 
receive a lot of half-fixed specimens such as most of us do.

"GEWF solution: an inexpensive, simple, and effective aid for the retrieval 
of lymph nodes from colorectal cancer specimens." 
Ken J. Newell, Barry W. Sawka, Brian F. Rudrick, David K. Driman. 
Arch Pathol Lab Med, May 2001;125:642-645.

GEWF solution consists of:
   100 parts absolute ethanol [or reagent alcohol, I'm sure]
     34 parts water
     16 parts strong (37%) formalin
     10 parts glacial acetic acid
mixed in the order listed [why does that matter?]

Open, pin out, and fix the specimen overnight in neutral buffered formalin
detach the pericolic fat 
postfix it overnight in GEWF solution
dissect out lymph nodes

The technique increased the average number of nodes recovered from 7 to 10, 
doubled the number of positive nodes found, and decreased the average size of 
positive nodes from 7 m to 5 mm. The authors found no interference with 
immunohistochemical stains.

Bob Richmond
Samurai Pathologist
Knoxville TN

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