Fuscus, February.

Before I get to fuscus, I have to say that I have HAD it with this month. Normally I start complaining about February around mid-January, and continue on every day until people start avoiding me. This year, I thought I could rise above it. I tried thinking positively. I tried reading Jung and Frankl to address my existential crisis. Last night I was up late listening to Jordan Peterson, and I thought I was doing pretty well.

But this morning, after coming out to a car completely encased in ice (not exaggerating), after seeing the sky the same color as the ground (greyish white) YET AGAIN, and after some other crap that I won’t go on about, I’m done. February just sucks. It’s not me, it’s you, February.

So where did February come from?

Since I sat down intending to write about the very nice Latin word fuscus, I thought maybe I’d look up the origin of the word February and see if there was some Latin that could help make me feel better. And there was! So I’m sharing what I found in the hopes that it may help others who have February issues.

February is usually said to be derived from the Latin februum, meaning anything that purifies or consecrates. This doesn’t fit my view of this month, but whatever. According to a prominent Roman grammarian (what a cool job, seriously) named Censorinus, who wrote De Die Natali (The Birthday Book) in 238 AD, there were tons of februamenta (rites of purification) going on in Rome during this time of the calendar year. Part of the purification was agricultural (clearing away dead stuff and getting the fields ready for planting). But it wasn’t just fields – houses, material items, and even the Romans themselves were februa (purified) in different ways, using different rites.

Wait, why all the purification?

In Roman tradition, February was originally the last month of the year, and, according to Ovid, it was “consecrated to the shades of the dead.” So along with acts of propitiation (appeasement, I had to look it up too), there were acts of purification to protect the living from evil spirits and also to banish the spirits at the end of the year so that the new year could begin in purity.

The image above is a drawing of the month of February from a fourth century calendar. The caption describes how to placate the ghosts that roam the earth in February. Okay – keeping angry ghosts from haunting the living – now we’re getting somewhere.

There must be something better, though.

Yes, there is. Some sources suggest that February actually comes from feber, a word which the Romans used to describe lamentation. YES! That’s it. I KNEW there had to be something in the name of this miserable month that reflected its true nature. Okay, the Romans were lamenting their deceased. But still. It fits. For the rest of the month, I’m going to say Lamentation instead of February and see if anyone notices.

Okay, back to fuscus.

For those of you brave enough to read this far, here’s a happy thing to offset all the misery. As you may know, there are a bunch of pigments you can see sometimes in tissues. One of them is called lipofuscin. It’s known as the wear-and-tear pigment, because it accumulates with age. Lipofuscin is composed of a bunch of lipids and proteins and has a yellow-brown appearance. It has no clinical significance – but you need to know it exists so you don’t confuse it with something else yellow-brown, like hemosiderin.

Here’s the good part. The first half of lipofuscin makes sense, since it’s composed partly of lipids. The second half is derived from the Latin word fuscus, which means dingy, brown, or dark – great Latin word choice, since lipofuscin has a dingy, brown appearance. So that’s why “obfuscate” means “to make unclear or obscure.” And it may be where we got the word “dusk” (from Middle English dosk, which came from Old English dox, which probably came from our Latin hero fuscus).

This is the weird kind of thing that makes me happy. I have no idea why finding the Latin connection between two seemingly unrelated words should make me happy in such disproportionate measure – or happy at all – but it does.

In this month of Lamentation, I’ll take happiness where I can get it.

What does “differentiation” mean?

Q. I’ve Googled and YouTubed this thing to death, and I still can’t grasp the meaning of “differentiation.”

It seems the opposite of its definition. To “differentiate” means to recognize what makes something different. But according to your post on tumor differentiation, well-differentiated tumors resemble (don’t look different from) their tissue of origin. I would think if something is well-differentiated, it would look very different from the thing it’s being compared to. Why is the use here opposite of its meaning?

A. I totally get where you’re coming from.

It’s REALLY frustrating in pathology when things are described in terms that don’t seem to make sense. You are not alone in questioning the use of this term!

The problem is that the word in question – differentiation – has a specific meaning in the real world. You’re exactly right in your definition: to differentiate between two things means to recognize what’s different or unique.

So you’d think that “differentiation” in the pathology world would mean the same thing: the recognition of things that are unique, different, or not the same. By logical reasoning, then, a “differentiated” tumor would be one that looked different from its cell of origin. And you’d think a “well-differentiated” tumor would be one that looked very different from its cell of origin.

Unfortunately, “differentiation” doesn’t have the same definition in the pathology world. So we have to put aside our logic and knowledge of vocabulary for a moment, irritating as that may be, and learn a new definition for this word.

The definition of “differentiation” in pathology-speak.

When we’re talking about tumors, the definition of “differentiation” is simply this: the degree to which tumor cells resemble their cell of origin. A well-differentiated tumor is one in which the tumor cells look very much like their cell of origin. A poorly-differentiated tumor (like the poorly-differentiated squamous cell carcinoma shown above) is one in which the tumor cells barely resemble their cell of origin.

That’s it. Yes, it’s an annoying word choice, because it is used here in a way that seems counterintuitive. But maybe it’s not as far off as it seems.

Maybe this will help.

I think about it (okay, rationalize it) this way. When cells are really immature, they don’t have a lot of features that make them look different from other cells. Myeloblasts don’t look very different than lymphoblasts, for example. So we could say that these immature cells are undifferentiated; it’s hard to tell what kind of cell they really are, and hard to tell them apart from other cells.

The same thing is true of the cells in poorly-differentiated tumors! The cells show practically no features that give away their identity; it’s hard to even tell what kind of cells they are. They are, in effect, undifferentiated.

If you think about “differentiation” this way (undifferentiated cells lack identifying features; it’s hard to tell what kind of cell they are), then the concept of tumor differentiation is a little easier to swallow. A little.

Tumor invasion and metastasis: are they the same thing?

Here are a couple great questions from one of my lovely students regarding invasiveness and metastasis.

Q. I have a quick question on today’s lecture. There is a slide near the end that has a picture of non-invasive carcinoma. For a tumor to be malignant, should it not be invasive?

A. Great question! I think you may be referring to the image above, which shows a gland with either severe dysplasia or carcinoma in situ.

Cancers are usually invasive, as opposed to benign tumors, which grow with pushing borders and are typically encapsulated.

However, very early cancers are called “carcinoma in situ”, which means they have not broken through the basement membrane yet (and thus are non-invasive). Every cancer has to start somewhere!

The only really definitive quality of malignancy is metastasis. If a tumor has metastasized, that is definite evidence of malignancy.

Q. But is invasiveness different from metastasis? That is, can a cancer metastasize without first invading tissue? Or are we talking about a tumor that has the ability to metastasize, but has not yet metastasized?

A. I’ll answer your questions separately.

1. Yes – invasiveness is different than metastasis.

  • Invasiveness is the ability of a tumor to extend into the surrounding tissue, and it is almost always a sign of malignancy. Benign tumors (with very few exceptions), are encapsulated and grow simply by expanding and pushing the surrounding tissue aside. Malignant tumors (with very few exceptions), are unencapsulated and grow by reaching into the surrounding tissue.
  • Metastasis is the ability of the tumor to move to a different location in the body and set up shop (start growing) there. Benign tumors NEVER metastasize. Malignant tumors usually do, although if detected early, they may be removed before they have the chance.

2. No: a cancer cannot metastasize without first invading tissue. In order to metastasize, tumor cells must first invade tissue, then make their way into vessels (either blood vessels or lymphatics), and then make their way out of those vessels and into new tissue.

3. Yes, the image above shows a non-invasive malignancy (carcinoma in situ), which is a malignant tumor that has not yet metastasized (or even invaded) yet. Left to its own devices, carcinoma in situ almost always becomes invasive carcinoma. As the tumor grows, some cells will most certainly develop the ability to become metastatic. So it’s way better to detect a carcinoma when it is in the carcinoma in situ stage rather than the invasive stage.