Thursday, March 10, 2011

Dawson Fingers: A Cocktail-Party Term Worth Knowing

Dawson Fingers (in box)
One of the nice things about teaching is that you frequently learn a lot from your students and residents. I had never heard of a radiological finding in multiple sclerosis known as "Dawson Fingers" until I was informed of it by Southern Illinois University second-year medical student Joshua Billington and neurology resident Laxmi Prasad Dhakal. "Dawson Fingers" are a purely radiological finding, which may be why the term is not found in neuropathology textbooks (at least not in the indices of eight different neuropathology textbooks that I consulted). Here's what Adams and Victor's Principles of Neurology (9th edition, page 889) has to say on the subject: "Especially diagnostic are oval or linear regions of demyelination, oriented perpendicularly to the ventricular surface; they correspond to the radially oriented fiber bundles of the white matter and periventricular veins. When viewed in sagittal images, they extend outward from the corpus callosum in a fimbriated pattern and have been termed 'Dawson Fingers'. These areas may extend into the centrum semiovale and may reach the convolutional white matter. Even one highly characteristic lesion is sometimes enough to confirm the diagnosis in the proper clinical circumstances; multiple lesions are more convincing. The presence of such lesions in the corpus callosum is diagnostically useful, as this structure is spared in many other disorders."  See the image above (from Adams and Victor, page 876) depicting Dawson Fingers on sagittal T2-weighted FLAIR MRI. The irony here is that this finding was named after a neuropathologist, James Walker Dawson (1870-1927), despite the fact that many neuropathologists are unfamiliar with the term (well, OK, maybe just me). Thanks to Dr. Dhakal and Pre-Dr. Billington for informing me of this eponymous finding -- one that neuropathologists should probably be able to throw around at any neuroscience cocktail party.

4 comments:

Marie said...

"Images of Dawson fingers" are the new "etchings" on the neuroscience cocktail party circuit. ;)

(I hope I'm not the only one that appreciates that since I thought it up really fast.)

(Plus, I found your last line to be inspiringly hilarious.)

Jeremy K. Deisch, M.D. said...

Dawson's fingers can be appreciated upon gross inspection of the brain. We have a few coronal sections of demyelination (i.e. M.S.) that we use for teaching medical students at UTSW. The case that I was using was a great example, in which the so-called "Dawson's fingers" were apparent on gross examination. But you had to know to look for them. Similar to your medical students, I recalled the term from neurology lectures in medical school, but I had never seen a good gross representation until recently.

Forensic Pathology Blog said...

Cool!

shipcolldoc said...

Dear Brian
Well, some neuropathologists have known this term for many years, and it is NOT a radiological term, originally; Dawson described perivascular extensions of acute demyelination in a finger-like pattern, hence the name. The radiologists (as is often the case) have just seized on an imaging correlation to an existing pathological description and now claim this as their own.