T minus 2 days until my follow-up appointment with Dr. B. I wanted to compile a summary of what I’ve learned about Hurthle Cells and “Hurthle Cell Lesions,” because I know from experience that although all of this info is really fresh in my mind right now, I will forget it. And it will be convenient to have it all here in one stash. I’d like to make a disclaimer ahead of time, just in case this blog ever goes live: I am not a doctor, or a scientist. What follows is my understanding based on the research I have done over the past two weeks. (If two weeks isn’t long enough to make me an expert on Abnormal Cells of the Thyroid, what would be?)
Hurthle Cells are, by definition, abnormal. From what I have read, there are some theories about why they form, but no one knows for sure. One of the main theories is that they are follicular cells that have transformed due to stress. They are frequently (some say always) seen in Hashimoto’s thyroiditis, a condition in which the body’s immune system starts attacking the thyroid gland for unknown reasons. They are extra large and full of lots more than normal mitochondria, which gives them a grainy appearance under the microscope. The mechanism for apoptosis–the process by which abnormal cells know they are abnormal and cause themselves to self-destruct, doesn’t seem to work for Hurthle cells. Also, unlike most other cells in the thyroid, most Hurthle cells (most sources say around 90%) have lost their ability to take up iodine, which means that RAI isn’t usually effective against Hurthle cell cancers. On the other hand, theydo produce Thyroglobulin, which makes this a useful marker for recurrence in Hurthle cell cancers, but only if the thyroid is completely removed by surgery and completely nuked by RAI. Ok, that’s it!
Actually, there is some information about biochemical processes and genetic mutations that I haven’t absorbed yet. I’m not convinced I need to know all that stuff, since I don’t plan on doing any clinical research on Hurthle Cells.
A “Hurthle Cell Lesion,” what I have, is a group of Hurthle Cells that have all decided to hang out together in one part of the thyroid gland. If the lesion is composed of more than 75% Hurthle cells, and it’s encapsulated with a distinct border separating it from the rest of the gland, it’s called a “neoplasm,” or tumor.
So here’s the thing. They can tell from FNA (Fine Needle Aspiration) if the lump/nodule/lesion is composed of mostly Hurthle Cells. I think they can tell from ultrasound if it’s encapsulated (this is one thing I want to ask about at my appointment on Tuesday). But they can’t tell if it’s cancer (carcinoma) or not (adenoma) without taking it out. That’s because most Hurthle cell tumors and lesions just sit there, doing mostly nothing. They aren’t aggressive, they don’t try to proselytize or set up colonies in other parts of the body. The only way to tell the difference between a benign Hurthle Cell tumor (adenoma) and a malignant one (carcinoma) is to take it out and dissect it, to see if it’s trying to invade the rest of the thyroid through the capsule wall (capsular invasion) or if it’s trying to invade the blood stream (vascular invasion). If it is doing either (or both) of those things, it’s classified as cancer, or “Hurthle Cell Carcinoma.” (HCC)
Hurthle Cell Carcinomas tend to occur in people over 50 (not me) with nodules larger than 4 cm (also not me) who do not have inflammation–like Hashimoto’s thyroiditis (also not me, since I DO have inflammation). So all of those things are WAY in my favor. Yay! Their prognosis is not as good as for people who have Papillary Thyroid Carcinoma (PTC, also known as “the good cancer,” because of its amazingly high cure rate) or Follicular Thyroid Carcinoma (FTC, only slightly less “good” than PTC), but some people feel that this has more to do with the fact that it usually occurs in an older population than with the actual characteristics of HCC.
Here’s something else. Hurthle Cell Carcinomas are really, really rare. So rare that when you go looking for info about Hurthle Cell cancers, because your doctor did a biopsy on your thyroid and found Hurthle Cells, and you are freaking out, trying to figure out what on earth a Hurthle cell is and if you should be worried or not, what you will mostly find is scholarly journal articles. Maybe a few posts on message boards.
The books about thyroid problems and even about thyroid cancers might have a sentence or two about friendly Hurthle Cells and their malicious carcinoma counterparts. Maybe even up to a paragraph. What they will mostly say is that Hurthle Cell Carcinomas are like Follicular Carcinomas, except that they don’t usually take up RAI, and they tend to metastasize more aggressively.
Those bloggers and memoirists (is that even a word?) who write about their thyroid cancer journeys almost all have Papillary Carcinoma (PTC), because 75-80% of thyroid cancers are Papillary. I might have found one person with a thyroid cancer story whose thyroid cancer was of a Hurthle cell variety. I’m actually about to go see if I can find that blog again… ETA: I did find that blog by the guy I thought had HCC, but he didn’t; he had PTC. But I also found this guy, who has written a very nice blog about his HCC journey.
Ok, so there are probably a few more details that I could cram in here (PTC variants, etc.), but I am not sure I could do them justice. If you want to read a scholarly article that covers all of this and more in some detail, try this one. I have found it to be pretty comprehensive, and I’ve actually printed it out to put in my file with my test results and other paperwork. You can also get lots of useful articles by googling terms like “Hurthle Cell Adenoma,” “Hurthle Cell Lesion,” and “Hurthle Cell Neoplasm.”