THYROID DISEASE
Ed Friedlander, M.D., Pathologist
scalpel_blade@yahoo.com

Cyberfriends: The help you're looking for is probably here.

Welcome to Ed's Pathology Notes, placed here originally for the convenience of medical students at my school. You need to check the accuracy of any information, from any source, against other credible sources. I cannot diagnose or treat over the web, I cannot comment on the health care you have already received, and these notes cannot substitute for your own doctor's care. I am good at helping people find resources and answers. If you need me, send me an E-mail at scalpel_blade@yahoo.com Your confidentiality is completely respected.

DoctorGeorge.com is a larger, full-time service. There is also a fee site at myphysicians.com, and another at www.afraidtoask.com.

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I'm still doing my best to answer everybody. Sometimes I get backlogged, sometimes my E-mail crashes, and sometimes my literature search software crashes. If you've not heard from me in a week, post me again. I send my most challenging questions to the medical student pathology interest group, minus the name, but with your E-mail where you can receive a reply.

Numbers in {curly braces} are from the magnificent Slice of Life videodisk. No medical student should be without access to this wonderful resource. Someday you may be able to access these pictures directly from this page.

I am presently adding clickable links to images in these notes. Let me know about good online sources in addition to these:

Freely have you received, freely give. -- Matthew 10:8. My site receives an enormous amount of traffic, and I'm handling about 200 requests for information weekly, all as a public service.

Pathology's modern founder, Rudolf Virchow M.D., left a legacy of realism and social conscience for the discipline. I am a mainstream Christian, a man of science, and a proponent of common sense and common kindness. I am an outspoken enemy of all the make-believe and bunk that interfere with peoples' health, reasonable freedom, and happiness. I talk and write straight, and without apology.

Throughout these notes, I am speaking only for myself, and not for any employer, organization, or associate.

Special thanks to my friend and colleague, Charles Wheeler M.D., pathologist and former Kansas City mayor. Thanks also to the real Patch Adams M.D., who wrote me encouragement when we were both beginning our unusual medical careers.

If you're a private individual who's enjoyed this site, and want to say, "Thank you, Ed!", then what I'd like best is a contribution to the Episcopalian home for abandoned, neglected, and abused kids in Nevada:

I've spent time there and they are good. Write "Thanks Ed" on your check.

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Especially if you're looking for information on a disease with a name that you know, here are a couple of great places for you to go right now and use Medline, which will allow you to find every relevant current scientific publication. You owe it to yourself to learn to use this invaluable internet resource. Not only will you find some information immediately, but you'll have references to journal articles that you can obtain by interlibrary loan, plus the names of the world's foremost experts and their institutions.

Alternative (complementary) medicine has made real progress since my generally-unfavorable 1983 review linked below. If you are interested in complementary medicine, then I would urge you to visit my new Alternative Medicine page. If you are looking for something on complementary medicine, please go first to the American Association of Naturopathic Physicians. And for your enjoyment... here are some of my old pathology exams for medical school undergraduates.

I cannot examine every claim that my correspondents share with me. Sometimes the independent thinkers prove to be correct, and paradigms shift as a result. You also know that extraordinary claims require extraordinary evidence. When a discovery proves to square with the observable world, scientists make reputations by confirming it, and corporations are soon making profits from it. When a decades-old claim by a "persecuted genius" finds no acceptance from mainstream science, it probably failed some basic experimental tests designed to eliminate self-deception. If you ask me about something like this, I will simply invite you to do some tests yourself, perhaps as a high-school science project. Who knows? Perhaps it'll be you who makes the next great discovery!

Our world is full of people who have found peace, fulfillment, and friendship by suspending their own reasoning and simply accepting a single authority that seems wise and good. I've learned that they leave the movements when, and only when, they discover they have been maliciously deceived. In the meantime, nothing that I can say or do will convince such people that I am a decent human being. I no longer answer my crank mail.

This site is my hobby, and I presently have no sponsor.

This page was last updated February 6, 2006.

During the ten years my site has been online, it's proved to be one of the most popular of all internet sites for undergraduate physician and allied-health education. It is so well-known that I'm not worried about borrowers. I never refuse requests from colleagues for permission to adapt or duplicate it for their own courses... and many do. So, fellow-teachers, help yourselves. Don't sell it for a profit, don't use it for a bad purpose, and at some time in your course, mention me as author and KCUMB as my institution. Drop me a note about your successes. And special thanks to everyone who's helped and encouraged me, and especially the people at KCUMB for making it possible, and my teaching assistants over the years.

Whatever you're looking for on the web, I hope you find it, here or elsewhere. Health and friendship!

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More of Ed's Notes: Ed's Medical Terminology Page

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What is Cancer?
Cancer: Causes and Effects
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HIV infections
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Lab Problem
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Alternative Medicine (current)
Alternative Medicine (1983)
Preventing "F"'s: For Teachers!
Medical Dictionary

Courtesy of CancerWEB

Endocrine Pathology
Virginia Commonwealth U.
Great pictures

Georgetown Med School
Endocrine Pathology

Tulane Pathology Course
Great for this unit
Exact links are always changing

Endocrine Disease
Mark W. Braun, M.D.
Photomicrographs

Thyroid Exhibit
Virtual Pathology Museum
University of Connecticut

Normal thyroid

WebPath Photo

Normal thyroid

WebPath Photo

Normal thyroid

WebPath Photo

Normal thyroid
C-cells stained
WebPath Photo

Goiter
From Chile
In Spanish

Thyroid
"Pathology Outlines"
Nat Pernick MD

Goiter
Fresh bleed into a nodule
EMBBS

Thyroid Histology
Ed's Histology Notes

{11803} normal thyroid, gross
{00135} normal thyroid, histology
{11755} normal thyroid, histology
{00138} goiter
{24613} goiter
{39460} goiter


Endemic goiter

    Mountaineers dew-lapped like bulls, whose throats had hanging at 'em wallets of flesh...

          -- Shakespeare, "The Tempest"

QUIZBANK

OBJECTIVES

INTRODUCTION

Endocrine
Cornell
Class notes with clickable photos

{08959} propylthiouracil effect
{24718} propylthiouracil effect

{24719} high-dose iodine effect

{09362} normal scan
{09363} cold nodule, right upper pole

HYPERTHYROIDISM (Lancet 362: 459, 2003)

CRETINISM

{49456} cretin, age 4 months

ACQUIRED HYPOTHYROIDISM (Lancet 363: 793, 2004 -- it's often missed even though this should never happen)

{24611} myxedema
{25468} myxedema
{25469} myxedema

Iodine deficiency
Epidemic goiter
KU Collection

BIRTH DEFECTS

Thyroid Malformations
From Chile
In Spanish

{49471} thyroglossal duct cyst, patient
{09245} thyroglossal duct cyst, histology

{21529} lingual thyroid

HASHIMOTO'S THYROIDITIS ("chronic autoimmune thyroiditis": NEJM 335: 99, 1996)

{09241} Hashimoto's, gross
{08960} Hashimoto's, histology
{08961} Hashimoto's, histology
{09242} Hashimoto's, histology
{37881} Dr. Hashimoto
{37882} Dr. Hashimoto "after 40 years of teaching"

Hashimoto's
From Chile
In Spanish

Hashimoto's thyroiditis
Germinal centers, damaged parenchyma
KU Collection

Hashimoto's
Anti-thyroglobulin antibodies
WebPath Photo

Thyroglossal duct cyst

Virtual Hospital

Hashimoto's

WebPath Photo

Hashimoto's

WebPath Photo

Hashimoto's

WebPath Photo

Hashimoto's
Anti-microsomal antibodies
WebPath Photo

NON-HASHIMOTO LYMPHOCYTIC THYROIDITIS

DEQUERVAIN'S SUBACUTE GRANULOMATOUS THYROIDITIS ("thyroid virus infection")

{09247} DeQuervain's
{24721} DeQuervain's

DeQuervain's

WebPath Photo

RIEDEL'S THYROIDITIS ("Riedel's struma"; review J. Clin. Endo. Metab. 87: 3545, 2002)

{49460} Riedel's

    A thankfully rare process in which fibroblasts proliferate and lay down collagen. Most patients are older women, who present with a rock-hard ("woody", etc.) neck mass.

    Riedel's does not respect the thyroid capsule, or anything else. (This makes it easy to tell from fibrosing Hashimoto's.) It mimics an invasive sarcoma, but there is no anaplasia or necrosis. Enough of the gland may be destroyed to produce hypothyroidism. Surgical exploration may be required to relieve pressure on the trachea. Fortunately, the disease generally stops before the patient asphyxiates.

GRAVES'S DISEASE

{09235} Graves's
{09237} Graves's

Graves's

WebPath Photo

Graves's

WebPath Photo

    This is a common problem caused by autoantibodies directed against the hTSH receptor. The receptor mistakes them for TSH. (Actually, some autoantibodies make the gland overgrow, others make it overwork.)

      Nobody knows the cause. The more you read about the immune derangements of this much-studied disease, the more confused you will get.

    Patients also usually exhibit ophthalmopathy (the usual "lid lag", etc., of hyperthyroidism, plus weak eye muscles plus excess collagen and ground substance behind the eyeball ("orbitopathy"), causing proptosis/exophthalmos). There are usually antibodies against both eye muscles and against the fibroblasts behind the eye.

{09355} Graves's exophthalmos
{09356} Graves's exophthalmos

    To complete the triad, patients often exhibit myxedema-like nodules confined to the anterior aspects of the lower extremities ("pretibial myxedema").

      * There are autoantibodies against fibroblasts here (J. Clin. Endo. Metab. 80: 3427, 1999). For some reason, fibroblasts on the shins, and only on the shins, evidently have TSH receptors (!) J. Endo. Inv. 19: 365, 1996.

      * Try a generous dose of a topical glucocorticoid for the pretibial myxedema (J. Clin. Endo. Metab. 87: 438, 2002).

{09360} pretibial myxedema
{25470} pretibial myxedema
{25471} pretibial myxedema
{25472} pretibial myxedema

    Whether or not the complete triad is present, "Graves's" is the usual cause of diffuse toxic goiter (weight up to 100 gm, seldom more, since there's little colloid). You're likely to hear a bruit over the gland (why?), and at surgery (oops), untreated Graves's will be beefy red.

      If you examine an untreated Graves's thyroid gland under the microscope ("oops!"), you'll see scanty colloid, typically being actively resorbed ("bite marks", "scalloping") around its edges.

{24717} Graves's with scalloping

        If the patient has been pre-treated with a goitrogen, you'll less colloid and more papillary formations (why?) If the patient has been treated with a huge dose of iodine to suppress thyroid hormone formation, you'll see a colloid goiter (why?)

    Today, most patients prefer to take a drink of I131, though they know this will eventually make them hypothyroid. The ophthalmopathy may require an ophthalmologist's care.

    NOTE: Sometimes antibodies merely block the effects of hTSH. This may be seen in both Hashimoto's disease and in "primary idiopathic hypothyroidism". Not rare, and may self-cure. NEJM 326: 513, 1992.

DIFFUSE NONTOXIC GOITER ("colloid goiter") / (MULTI)NODULAR GOITER

{21053} colloid goiter
{21054} colloid goiter
{19502} colloid goiter, around 100 gm
{09354} colloid goiter, gross
{19505} colloid goiter, histology
{19511} colloid goiter, histology
{10825} nodular goiter
{12710} nodular goiter (this was billed as "Hashimoto's"; I doubt it)
{39052} nodular goiter (dominant nodule was called "adenoma", heh heh)
{09238} nodular goiter, gross
{49451} nodular goiter, gross
{09240} nodular goiter, histology
{49465} nodular goiter, they decided to operate

Nodular goiter

WebPath Photo

Nodular goiter

WebPath Photo

Big inactive follicles
Nodular goiter / Could be other things too
WebPath Photo

    Diffuse enlargement of the thyroid gland was historically due to epidemic goiter, caused by lack of iodine in the diet (i.e., any community far from the seashore). This was often exacerbated (or even primarily caused by) goitrogens in the diet.

    WARNING: The iodine-deficiency thyroid gland is under heavy TSH stimulation (why)? When an iodine-deficient patient is treated with a large amount of iodine, acute hyperthyroidism and even hyperthyroid crisis can supervene. This is the dread Jod-Basedow phenomenon.

      "Jod" is German for "iodine", and "Basedow's disease" their term for any hyperthyroidism.

    Sporadic diffuse goiter is often hereditary, due to (1) inability of stomach or thyroid to take up iodine; (2) lack of peroxidase to link iodine to tyrosine; (3) inability to recycle iodine in the thyroid gland; (4) inability to crunch the two iodotyrosine moieties together to make T4. Or a person may lack TSH receptors.

    A small diffuse goiter is almost the rule rather than the exception around menarche.

    Early in its development, the colloid goiter shows hyperplasia (i.e., tall cells, maybe piling-up) under the influence of TSH. Later, the cells appear to give up, and the gland becomes a mass of oversized, colloid-packed follicles. Of course, the process is never really uniform, and eventually the diffuse nontoxic goiter turns into a multinodular goiter. By the time the gland reaches over 100 gm, the multinodular stage is usually well-underway.

    In a multinodular goiter, there are many nodules, most composed of follicles more or filled with colloid, others representing sites of old hemorrhage and fibrosis ("Feel my goiter!" "Oops, I bumped my neck!") You can see squamous metaplasia, foam cells, masses of hemosiderin, foreign-body granulomas, and many other interesting things.

    Rule: If the excised portion of thyroid contains two "adenomas", go ahead and call it a nodular goiter.

    A microscopic survey of a nodular goiter is enough to make anyone think about Nowell's law seriously, and this is supported by the finding that many genetically distinct clones of cells with various functional problems. (Clonality in the nodular goiter revisited: Am. J. Path. 134: 141, 1989; hot-spot ras mutations in goiter nodules: Mol. End. 4: 1474, 1990). However, the common genetic basis remains obscure. (J. Clin. Endo. Metab. 87: 4264, 2002). Multinodular goiter often arises de novo, either sporadically or in certain anti-oncogene deletion syndromes (notably Cowden's).

    Usually there are no new functional problems with the thyroid gland in multinodular goiter, but sometimes a clone of cells may turn "hot", causing hyperthyroidism. Fortunately, carcinoma very seldom arises in multinodular goiter, and most "cold nodules" removed from thyroid glands turn out simply to be sleepy nodules from multinodular goiters.

Thyroid Tumors I
From Chile
In Spanish

Thyroid Tumors II
From Chile
In Spanish

Thyroid Tumors
Histopathology and essay
For pathologists

THYROID ADENOMAS

{24724} thyroid adenoma, gross
{13363} thyroid adenoma, gross
{09248} thyroid adenoma, gross
{09250} thyroid adenoma, gross
{09777} thyroid adenoma, gross
{39965} thyroid adenoma, gross
{49453} thyroid adenoma (center has liquefied)
{49454} thyroid adenoma
{19523} thyroid adenoma, histology
{19529} thyroid adenoma, histology

Follicular adenoma
Ed Uthman's Pathology Gallery

Adenoma

WebPath Photo

Adenoma

WebPath Photo

Adenoma

WebPath Photo

Thyroid follicular adenoma

Virtual Hospital

    The vast majority of dominant thyroid nodules are either benign adenomas or just big nodules in a multinodular goiter. This is good, because thyroid nodules are very common (around 5,000,000 in the U.S.) You'll learn to manage these clinically. Most patients are adults, and there is a modest female preponderance.

    As you would expect, thyroid adenomas are composed of thyroid follicles ("follicular adenomas"). Don't worry about the useless subclassification given in "Big Robbins"; they all behave pretty much the same, i.e., they are harmless or might perhaps make excess T4 and/or T3.

      * The major pathologist-fooler is the "hyalinizing trabecular adenoma", with balls of cells embedded in shelves of basement membrane; it can include psammoma bodies and orphan-annie eye nuclei. Leave diagnosing it to us (stain Am. J. Clin. Path. 122: 506, 2004). It has both a benign and malignant (i.e., capsular invasion) form.

      * Hyperfunctioning nodules, not surprisingly, often have (Nowell's law) gotten mutated TSH receptors stuck in the "on" position: J. Clin. End. Metab. 81: 1584, 1996; we can assume the ones that don't have something else wrong in the cAMP signal pathway.

      T3 toxicosis usually means adenoma. Why? Hint: Think of Nowell's Law.

      Less often, one gets unusually big, or causes pressure symptoms.

      * Molecular profiling of cells in fine needle aspirates to predict malignancy is a promising area (J. Clin. Inv. 113: 1234, 2004), but we're not going to give up microscopy or risk leaving something bad in place anytime soon.

    Fortunately, the genes that cause adenomas don't seem to be the same ones that produce thyroid carcinomas, and thyroid adenomas have virtually no tendency to turn malignant. (* You may see slight atypia in these tumors. Let the pathologist worry about it.)

    You can remove adenomas surgically, or suppress them by using thyroxine to suppress TSH. (Ignore "Big Robbins" about how adenomas should "theoretically" be "autonomous"; the idea that "tumors are free of controls on their growth" is rank superstition.)

    * Ask a pathologist whether he or she has ever seen a C-cell adenoma. No follicles, cells may spindle, and stain for calcitonin.

PAPILLARY ADENOCARCINOMA ("Orphan Annie's Tumor")

{24725} papillary carcinoma, gross
{24723} papillary carcinoma, histology
{26792} papillary carcinoma, histology
{26795} papillary carcinoma, histology
{26798} papillary carcinoma, histology
{20291} world's smallest papillary thyroid cancer

Papillary thyroid cancer
Photo and mini-review
Brown U.

Papillary carcinoma

WebPath Photo

Follicular carcinoma
Orphan Annie Eyes
WebPath Photo

Orphan Annie, psammoma bodies

WebPath Photo

Papillary Thyroid Cancer
Dino Laporte's PathosWeb

    This is a common, often-multifocal (separate primaries NEJM 352: 2406, 2005) cancer, common in adults, and not unknown in children.

    The harder you look for papillary carcinoma of the thyroid, the most you find. The "greatly increased rate" seen in autopsies of Hiroshima survivors was probably real, though these glands were meticulously sectioned in search of small cancers.

      There's no question that irradiating the thyroid gland (for a good reason or for "big thymus", tonsils, acne, or what-have-you) gives an increased rate of papillary (and probably follicular) carcinoma; the increased risk from radioactive iodine therapy of Graves's is very small. The risk from external beam radiation continues for life (Endo. Metab. Clin. N.A. 19: 495, 1990), with cancers typically appearing decades later; fortunately, radiation-induced cancers tend to be tame (Arch. Ped. 148: 260, 1994), but don't expect them to remain dormant (Ann. Surg. 239: 536, 2004). Chernobyl's children and their papillary thyroid cancers: Cancer 74: 748, 1994; nobody knows exactly why, but it's a real problem, maybe kids are more susceptible to hot iodine. Thankfully most of these are non-lethal.

      * The cancer has its own oncogenes, PTC-1, -2, and -3, which turned out to be particular rearrangements of RET (Endocrinology 137: 375, 1996; J. Clin. End. Metab. 81: 3360, 1996; update Cancer 104: 943, 2005).

      * Also important in the genesis of many papillary cancers is the tyrosine kinase BRAF (Hum. Path. 36: 694, 2005); there is a signature translocation in radiation-induced tumors (J. Clin. Inv. 115: 94, 2005).

    The histology is that of a papillary adenocarcinoma (i.e., inside-out glands growing like a tree, the stalk being the trunk and branches, the cells being the leaves.) A good rule: Any reasonably well-differentiated thyroid tumor with any papillary area will act like a papillary carcinoma of the thyroid. (Even if there are also follicles: Arch. Surg. 138: 1362, 2003; Cancer 97: 1181, 2003; and many more).

      Pathologists usually (but not always) see the "Orphan Annie eye" nuclei (Annie was, of course, a character in a comic strip where no one had irides or pupils.) These nuclei have marginated chromatin and optically clear centers. It's a fixation artifact. Another good rule: Any reasonably well-differentiated thyroid tumor with Orphan Annie nuclei will act like a papillary carcinoma of the thyroid.

        * Ask a pathologist to show you an electron micrograph of a cytoplasmic invagination into a nucleus of one of these cancers.

        * Future pathologists: Any cell (and notoriously, endocrine cells and healthy lymphocytes) that is poorly-fixed prior to tissue sectioning can exhibit an "orphan annie eye nucleus".

      Another favorite finding is psammoma bodies. (* Future pathologists: You see these in normal chorioid plexus, normal pineal, papillary carcinoma of the thyroid, serous cystadenocarcinoma of the ovary, meningioma, and somatostatinoma.) Again, these promise the tumor will behave like papillary carcinoma.

      * Sclerosing variant: Cancer 66: 2306, 1990. Keratin 19 as marker for papillary carcinoma (Am. J. Clin. Path. 92: 654, 1989). Histologic grading (aggressive vs. non-aggressive): Am. J. Clin. Path. 101: 651, 1994. There is a familial version that is ill-behaved: Arch. Surg. 131: 676, 1996; Lancet 353: 637, 1999.

    Except for a few uncommon subtypes, these lesions are noted for being non-aggressive. Often first diagnosed as a metastasis in a cervical node, survival is the rule. Like most carcinomas, it prefers the lymphatic route, and can ultimately spread by the bloodstream.

      Despite its usually gentle nature, papillary carcinoma does occasionally kill people, typically by asphyxiation. It is also the breeding ground for anaplastic carcinoma of the thyroid.

      The diffuse sclerosing form presents as a goiter composed entirely of papillary cancer. The abundant psammoma bodies impart a remarkable gritty feel when cut. It's more likely to be in the lymph nodes at presentation than other forms of papillary cancer, but the prognosis is still generally good (Eur. J. Surg. Onc. 29: 446, 2003).

      The tall-cell variant features oncogenic met and has a much worse prognosis (Cancer 98: 1386, 2003).

      * More on prognosticating the disease: Cancer 68: 324, 1991. Some histologic subtypes are nastier than others. Epithelial membrane antigen positivity seems to be a strong marker for aggressive behavior: Cancer 70: 2326, 1992.

    "Orphan Annie's tumor" reminds us of papillary carcinoma of the thyroid:

    • It primarily affects younger women;
    • It tends to stay around for years without getting any bigger;
    • It is usually well-behaved and seldom kills people;
    • Its nuclei exhibit marginated chromatin, producing the "Orphan Annie's eye" appearance
    • Medical Word Roots The psammoma bodies (Greek psammos means "sand") recall the name of Orphan Annie's faithful dog, Sandy.

    * Watch for Tc99-sestamibi as a new way to detect metastatic papillary thyroid carcinoma (also bresat, oat cell, and of course parathyroid).

    Relative frequency of detected thyroid carcinomas:

      Papillary... 65%; the large majority will not die of it

      Follicular... 25%; maybe 50% will eventually die of it if it is "frankly invasive" at diagnosis, though it may be much later than 5 years

      Medullary... 5%; 50% 5-year mortality if sporadic (probably less nowadays), much better if you picked it up early as part of workup of a family

      Anaplastic... 5%; almost all will die of it in short order

    * All about thyroid and parathyroid cancer: Otol. Clin. N.A. 23(6): 1181, 1990. Future pathologists: It's claimed that dipeptidyl aminopeptidase IP stain of cytology preparations distinguishes benign follicular cells (negative) from malignant ones (positive): Am. J. Clin. Path. 96: 306, 1991; Diag. Cyto. 19: 4, 1998; still holding up Arch. Surg. 139: 83, 2004. this seems to work but isn't in widespread use.

FOLLICULAR ADENOCARCINOMA (pathologists see Cancer 100: 1123, 2004)

    This is a more aggressive thyroid carcinoma that generally makes follicles. Grossly, it may be obviously malignant, or there may be metastases. More often, malignancy is established by demonstrating that a thyroid nodule contains groups of cells invading vessels (not lymphatics; for some reason, this particular cancer prefers the vascular route of invasion.

    If the tumor invades through (not just into) its "capsule", this is also a criterion for malignancy, though it is far less ominous than vascular invasion.

    There are no good fibrovascular papillae, Orphan Annie nuclei, or psammoma bodies. The tumor cells often take up radioactive iodine, which is useful both in scanning for metastases and for treating them (clinical review Cancer 95: 488, 2002). This tumor (and papillary carcinoma) may be modestly hTSH dependent, and thyroid hormone administration may suppress them temporarily.

    * Pathologists hate this lesion, as it's difficult to tell from one of the much-more-common follicular adenomas / hyperplastic nodules. There is a "minimally invasive subtype" with a very good prognosis (Cancer 91: 505, 2001). Criteria for handling follicular lesions Am. J. Clin. Path. 117: 143, 2002.

    The prognosis is always guarded. This tumor tends to metastasize to lungs (via veins, of course) and bone.

{09255} follicular carcinoma of thyroid, histology. Trust me, this was invading a vessel
{39838} follicular carcinoma of thyroid, histology. Trust me, this was invading a vessel

Follicular thyroid cancer
Photo and mini-review
Brown U.

MEDULLARY ADENOCARCINOMA (Mayo Clin. Proc. 67: 934, 1992; Surg. Clin. N.A. 75: 405, 1995; Am. J. Med. 103: 60, 1997).

    This is cancer of the C-cells (or at least diffentiating as C-cells; see Cancer 74: 928, 1994). Its stroma is usually (* not always) laced liberally with calcitonin pleated into amyloid.

    As you remember, this cancer is caused, at least in part, by loss of both copies of the MEN-II anti-oncogene on chromosome 10. As you'd expect, in MEN-II it is very common and often multifocal, and occurs at any age.

      Sporadic cases (older folks) also lack the protective genes. With the cloning of the RET gene (the MEN-II gene), we've discovered different alleles producing different complexes (J. Clin. End. Met. 79: 590, 1994; J. Clin. End. Metab. 81: 1780, 1996), some families get only medullary carcinoma (Nature 367: 319, 1994; J. Clin. Endo. Metab. 87: 1674, 2002). We can test people for the gene (Surgery 116: 124, 1994) and prophylactic thyroidectomy is now routine (J. Am. Coll. Surg. 195: 159, 2002).

      The cancer tends to be indolent, with stage at surgery and calcitonin levels shortly after surgery the only prognosticators: Cancer 77: 1556, 1996.

    As befits cancer of the C-cells, the tumor often makes calcitonin. In extreme cases, tetany may result.

      You may also gets ACTH (Cushingism), VIP (diarrhea), serotonin (instant carcinoid syndrome), and a variety of other things.

    * Future pathologists: the very rare amyloid goiter features amyloid AA and extensive fatty ingrowth. It remains a minor mystery of medicine.

{49355} medullary carcinoma of thyroid, gross
{49356} medullary carcinoma of thyroid, gross
{49365} medullary carcinoma of thyroid, gross
{49366} medullary carcinoma of thyroid, gross. Of course, you couldn't diagnose any of these four without histology.
{09265} medullary carcinoma of thyroid, histology
{09266} medullary carcinoma of thyroid, histology
{37160} medullary carcinoma of thyroid, histology; Congo Red stain
{37163} medullary carcinoma of thyroid, histology; crystal violet stain (amyloid is scarlet, all else is Navy Blue)

Medullary carcinoma

WebPath Photo

Medullary carcinoma
Congo red
WebPath Photo

      Future endocrinologists: Anybody you suspect of harboring MEN-II gene (i.e., they have a personal or family history of hyperparathyroidism, pheochromocytoma, mucosal neuromas, and/or medullary carcinoma of the thyroid) needs a check. One technique is to infuse calcium and/or pentagastrin; a brisk rise in blood calcitonin means pre-malignant hyperplasia of C-cells, and you need to do something about it. All about provocative calcitonin testing: Am. J. Hum. Genet. 52: 335, 1993; this will probably remain a supplement to RET gene testing.

    * People with C-cell hyperplasia are likely to have elevated serum calcitonin (usually asymptomatic). The RET mutation is the usual cause; mutated succinic dehydrogenase can also do this but does not seem to lead to actual neolasia (J. Clin. Endo. Metab. 88: 4932, 2003)

    Nowadays, looking thyroids to spot pre-malignant hyperplasia of C-cells ("medullary carcinoma in situ") is well-worthwhile. You look for anaplasia, not just numbers: Cancer 77: 750, 1996.

ANAPLASTIC ADENOCARCINOMA ("undifferentiated carcinoma"; review Cancer 66: 321, 1990)

    Very, very ugly, both histologically and clinically. We believe that most of these tumors arise in a previous papillary or follicular thyroid carcinoma (Nowell's law triumphant); this has been confirmed by genetic studies (Cancer 103: 2261, 2005).

    * Ignore the subclassification of the old WHO system. Most of the small cell anaplastic carcinomas were really lymphomas; most of the large cell anaplastic carcinomas were for real. There are many variations of the theme of anaplasia (Arch. Path. Lab. Med. 111: 1169, 1987; these tumors generally light up with both keratin and vimentin). Fibrotic anaplastic carcinoma mimicking Riedel's: Am. J. Clin. Path. 105: 388, 1996.

    * A Canadian group's experience with very aggressive treatment; Cancer 91: 2335, 2001. This is the only optimistic report ever.

{09264} anaplastic carcinoma of thyroid, histology
{37004} anaplastic carcinoma of thyroid, cytology

Anaplastic carcinoma of the thyroid
Clear vascular invasion
Pittsburgh Pathology Cases

    Primary thyroid lymphoma is an uncommon B-cell neoplasm arising usually in Hashimoto's. Look for malignant lymphocytes inside the follicles.

{10934} lymphoma of the thyroid
{10937} lymphoma of the thyroid

    Thyroid cancer: CA 46: 261, 1996

ATROPHY OF THE THYROID

Thyroid Atrophy
From Chile
In Spanish

{17447} burned-out thyroid; this could be anything from old I131 injury to old Hashimoto's to Riedel's to a really gone patch in a nodular goiter.

    Every so often, at autopsy of an adult, the thyroid is shrivelled to a miniature thyroid-shaped nubbin of white scar tissue, weighing perhaps a gram. Trying to guess the cause is fun but usually futile.

    If you see giant nuclei and hyalinosis of small arteries, perhaps the patient forgot she had once taken a drink of I131. Other cases may be burned-out Hashimoto's or DeQuervain's. Of course, if there's no pituitary gland, the thyroid may have died of under-stimulation.

THYROID TESTING (see Lancet 357: 619, 2001)

    Serum T4 will give you the total bound plus unbound. Serum free T4 will give you the unbound, but it is more expensive. Serum T3RU (T3 resin uptake) is an unfortunately-named test that gives you a value inversely proportional to the number of unbound sites on the serum thyroid hormone carrying proteins (remember them?) Multiply T4 and T3RU to get "free thyroxine index", a measure of the biologically active hormone.

    Quiz: Who remembers what proteins carry T4 and T3? Answer: Thyroxine-binding protein (TBG, lion's share), transthyretin ("prealbumin"), and albumin. What's the best way to raise TBG? Take estrogen. What does this do to total T4? T3RU? Free T4? TSH?

    Serum T3 of course measures the active hormone. You can get a serum free T3 also. Some toxic nodules make T3 instead of T4, so it's often worth checking (Am. J. Med. 96: 229, 1994).

    Quiz: Suppose somebody took T4 to lose weight and got sick it ("factitious hyperthyroidism"). How would the tests be affected? Suppose the person took pure T3 instead?

    The newer, super-sensitive TSH assays are a good way to screen for hyperthyroidism (TSH in primary, in secondary or tertiary) and hypothyroidism ( in primary, in secondary or tertiary). Some people say that patients may actually be suffering from symptomatic thyroid disease if hTSH is abnormal but T7 is in the normal range (i.e., "not everybody has the same 'normal' thyroid hormone levels".) hTSH has long been the best screen for cretinism.

    On thyroid scans, cold nodules are the ones most likely to be malignant (why?) Hot nodules are the ones most likely to produce hyperthyroidism. You'll learn how to manage both on rotations. In hyperthyroidism due to most causes, the gland will be hot, but in struma ovarii, DeQuervain's, or factitious hyperthyroidism, it will be cold (why?)

    Serum thyroglobulin will often be increased in thyroid cancers (papillary, follicular) or in DeQuervain's (why?). For use of thyroglobulin in detecting recurrences, read Arch. Int. Med. 150: 437, 1990. You can use an immunoperoxidase stain for thyroglobulin to show that a particular cancer is of thyroid origin.

    When you are monitoring thyroid hormone replacement in somebody who has been hypothyroid, the conventional wisdom is to try to avoid their becoming even a little bit hyperthyroid, since this will supposedly lead to osteoporosis in the long run. However, some people actually do not feel well until the free T4 is somewhat above the upper limit of normal (Br. Med. J. 326: 295, 2003), and I'd trust the body's wisdom on this. Currently, clinicians make sure that hTSH stays in the normal range. If, on the other hand, you are administering thyroxine to suppress a hTSH-dependent thyroid cancer, be sure that you give enough so that hTSH levels remain zero.

    During serious illness or injury, some people have diminished intracellular conversion of T4 to T3 by the deiodinases.

      This is mediated by the cytokines of the acute phase reaction, and to be usual, correlating with the drop in albumin (Surgery 123: 560, 1998). Nobody knows whether this is good (diminishing energy use during convalescence) or bad, and replacement Of course, labs can be normal or abnormal, and the patients can feel well or ill.

      "Euthyroid sick syndrome" is recognized, for research purposes, in patients who are sick with something serious have low T3's and high rT3's (i.e., T4 is getting metabolized wrong). The conventional wisdom is that you do not treat it (i.e., you do not administer extra T4 or T3); not everybody agrees (Am. Heart. J. 135: 187, 1998).

      There are two schools of thought on managing thyroid replacement therapy -- by the numbers or by how the patient feels. I have often wondered whether (1) a "normal" serum T4 might still be low for that person, and whether (2) a "normal" serum T4 might not mean a normal T4 in the brain milieu. Physicians who fear being sued decades later for "causing osteoporosis" are reluctant to approve patients who feel best when they take a bit more thyroxine than "the lab tests say they need". I'm not a clinician, but we have a saying in pathology, "Listen to the patient, not the numbers." I'm not alone (Br. Med. J. 320: 1332, 2000; Br. Med. J. 326: 295, 2003)

      * This brings us to a current fad diagnosis, Wilson's Syndrome. Supposedly this results from faulty metabolism of T4 into rT3 at the tissue level. People interested in complementary medicine are invited to take their body temperature repeatedly, and if it is "a few tenths of a degree below 98.6" at any time of the day, and they have any of a huge list of symptoms, then the diagnosis is considered established and the patient gets a series of "complementary" remedies. Before you diagnose or treat yourself or somebody else, please consider these facts:

      • One E. Denis Wilson M.D. popularized this in "Wilson's Syndrome: The Miracle of Feeling Well", 1996

      • A medline search (1999) shows no scientific publications by anybody named Wilson on the subject of clinical hypothyroidism

      • The 1999 directory of US medical specialists does not list any Denis Wilsons, Dennis no-other-initials Wilsons, or E-- D-- Wilsons.

      • Average normal body temperature is 98.2, so most people would self-diagnose as having Wilson's syndrome

      • If the model is true, people with "Wilson's syndrome" would have relatively high rT3 levels at presentation. A medline search (1999) shows that no one has reported looking at this. If the proponents believed their own claims, they would do so. It would seem to me that the burden of proof is on them.

      • On the other hand, it seems entirely plausible that some people do not make as much thyroid hormone as is right for them, and they feel the effects of this lack. I cannot fault a physician for trying a small amount of thyroxine supplementation in a patient with vague complaints suggesting hypothyroidism.

      * Do you remember those deiodinases? Selenium takes the place of sulfur in their cysteines!

    In suspected Graves's disease and Hashimoto's disease, you can order a battery of anti-TSH receptor autoantibodies ("thyroid stimulating antibody", "long-acting thyroid stimulator"=LATS), anti-thyroglobulin antibodies, and anti-microsomal antibodies. Interpretation is rather cloudy, though very high titers of anti-microsomal antibodies (against the peroxidase autoantigen, of course) is pretty specific for Hashimoto's. Today we call these "anti-TPO", anti-thyroid peroxidase.

    If you've got a bump in your thyroid, your neighborhood pathologist will be happy to fine-needle-aspirate it, and look at the cells on a slide. How to do it right: J. Cln. End. Metab. 79: 335, 1994; Mayo Clin. Proc. 69: 44, 1994. Using it with ultrasound to be sure you hit the itty-bitty nodules: Otolar. 123: 700, 2000. This is really a screening technique to find out which bumps to cut out, and it is the one instance in which a decision to perform such serious surgery may be based on a few cells in a cytology smear. The practice is now standard, and has greatly reduced the number of people who need to be operated for diagnosis.

    Please remember that we CANNOT tell benign from low-grade-malignant follicular lesions of the thyroid using fine-needle aspiration.

    A surgeon should remove the bump if the fine needle aspirate shows:

      • Orphan Annie eye nuclei
      • nothing but little tiny follicles;
      • Hürthle cells (and it's not Hashimoto's)
      • anaplasia
      • even one mitotic figure.

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