Thread by @DavidSteensma

#HematologyTweetstory 23: a thread on how the confusing "myelo-" nomenclature arose. Myelodysplasia, AML, myelofibrosis. Myeloma. Myelomeningocele, poliomyelitis, and other neurologic conditions. Osteomyelitis (depicted). They *sound* connected - but are unrelated. #MDS #MMsM /1

I think I first did a @PubMed search on “myelodysplasia” around 1997, looking for a paper about #MDS marrow. But the search returned a bunch of articles about spina bifida, not about bone marrow. This was a surprise. The @SpinaBifidaAssn even has a seal named Myelo as a mascot./2

The linguistic connection in English (and other languages) between marrow and brain/spinal cord is unexpected, and results from a historical misconception./3

Of course, there are plenty of linguistic relics embedded in language have remained long after the ideas that spawned them were found to be obsolete:e.g.,“Influenza" has nothing to do with influence of the stars, despite its origin from an Italian folk word blaming the heavens./4

Similarly, the disease we call “malaria” – mal (bad) + aria (air) – is transmitted not by swampy, fetid or otherwise toxic air (i.e., the “miasma theory”), but by the parasite-laden Anopheles mosquitoes that fly through that air./5

The medical English myelo- comes from ancient Greek,in which the same word μυελός (myelos) was used to describe three things: bone marrow, the spinal cord, and, to a lesser extent, the brain. Why the same word for these unconnected organs/tissues, Dr. Hippocrates? /6

Let’s look at this from the perspective of the ancients. Topologically, the thick spinal cord probably appeared to be a sort of “marrow” filling the vertebral column, and the brain the “marrow” of the skull. No other bones encapsulate such a large and mysterious structure./7

In a weird twist for conceptual brain-marrow connectivity, in 2018 tiny channels directly connecting the skull marrow to the surface of the brain were detected by @MatthiasNahrend and colleagues. /8
hms.harvard.edu/news/skull-sur…

There's also a compelling theory that our hominid ancestors depended on eating marrow to feed growing brains. That makes sense – after apex predators stripped away everything else from a fresh kill, marrow was the most calorie-rich substance remaining. /9 discovermagazine.com/planet-earth/a…

This brain/marrow connection wasn't limited to Greece. I’m told that in the Talmud, מֹחַ (moach) is used to refer to both mind & marrow. The word makes one appearance in the Bible, in the Book of Job. (I once took a class on Job – textually & theologically a difficult book.)/10

Back to the modern era. In 1854, Rudolf Virchow in Berlin coined the term "myelin-" to describe a nerve sheath, as summarized in this nice history by Anne Boulerne @uic This is from Skinner's etymology book depicted above./11 ncbi.nlm.nih.gov/pmc/articles/P…

Plato in Timaeus considered the brain and spinal ‘marrow’ as a special form of bone marrow (Timaeus, 73) in which 'the gods implanted divine seed’. Plato also believed semen came from the spinal cord, but this idea was, to say the least, not universally accepted.../12

Chinese traditional medicine makes a similar link. Chinese thought the head was filled with a nourishing marrow, thanks to an energy called “kidney essence.” “The kidney nourishes marrow, and the brain is a sea of marrow" is a core concept in Chinese traditional medicine./13

When first described in the 1840s, the disease we now call #multiplemyeloma was noted for the way it damaged bone plus a link with what became known as Bence Jones proteinuria. @RobertK68033234 and I have written several histories of myeloma such as this one. @VincentRK has, too.

Myeloma was first considered a form of "mollities ossium”, which meant “softness of the bone”, from the Latin “mollis”, softness or pliant. The effect of this newly described disease on bone was emphasized in early reports such as those of Solly in 1844./14

Incidentally, the word “molly” was used to describe the ‘molly house’, an 18th century British institution frequented by people considered effeminate or 'soft' by others. @atlasobscura recently published a fascinating history about these institutions./15 atlasobscura.com/articles/regen…

The term “multiple myeloma”, emphasizing plasma cell tumors arising from marrow in numerous sites, was introduced in 1873 by J. von Rusitzky from Kiev, of whom little is known other than that he once worked in the lab of Friedrich von Recklinghausen (depicted) in Strasbourg. /16

During an autopsy, von Rustizky noted 8 separate tumors of the bone marrow in a patient, which he called “multiple myelomas." The patient was a 47 y/o man who presented with a slowly enlarging tumor in the R temple. In Slavic countries, 'von Rustizky disease" was long used./17

I've written in other tweetstories about the origin of myeloid to describe marrow and MDS. Regardless of the potential confusion, I think we can agree “Mylotarg” – the brand name for #gemtuzumab ozogamicin, which targets myeloblasts – is misspelled. Should be Myelo-targ!😉/End