Thyroid gland
The thyroid gland is an important little endocrine organ in the anterior neck. It is not infrequently afflicted by cancer... but the common cancer has such a good prognosis there is debate about how aggressively it should be treated. The cytopathology of the thyroid gland is dealt with in the thyroid cytology article. It frustrates a significant number of pathologists, as the criteria for cancer are considered a bit wishy-washy.
Thyroid specimens
They come in 3 common varieties
- Hemithyroid.
- Done to get a definitive diagnosis.
- May be a "completion" - removal of the other half following definitive diagnosis.
- Total thyroid.
- Done for malignancy or follicular lesion.
- FNA (fine needle aspiration).
- Done to triage patients/rule-out malignancy - discussed in the article thyroid cytopathology.
Gross pathology
- White nodules - think:
- Lymphoid tissue.
- Papillary thyroid carcinoma - may be calcified.[1]
Diagnoses
Common
- Nodular hyperplasia -- most common.
- Lymphocytic thyroiditis.
- Papillary thyroid carcinoma (PTC) -- most common cancer.
- Follicular adenoma.
- Follicular thryoid carcinoma.
- Parathyroid tissue.
Pitfalls/weird stuff
- Thyroid tissue lateral to the jugular vein = metastatic PTC... even if it looks benign.
- Hashimoto's disease may have so many lymphocytes that it mimics a lymph node -- may lead to misdiagnosis of PTC.
- Parasitic nodule: clump of thyroid that is attached by a thin thread... but looks like a separate nodule; may lead to misdiagnosis of PTC.
Diagnostic keys
The following should prompt careful examination:[2]
- Architecture: microfollicular, trabecular, solid, insular.
- Thick capsule.
- Necrosis - rare in the thyroid.
Thyroid IHC - general comments
- Not really useful.
- Papers with very small sample sizes abound.
Follicular thyroid carcinoma vs. papillary thyroid carcinoma
Parathyroid tissue
General:
- Identification of normal can be tricky.
Features:[5]
- Low power:
- May vaguely resemble lymphoid tissue - may have hyperchromatic cytoplasm.
- Does not have follicular centres like a lymph node.
- May form gland-like structure and vaguely resemble the thyroid at low power.
- Cytoplasm may be clear[6] - key feature.
- Surrounded by a thin fibrous capsule.
- May vaguely resemble lymphoid tissue - may have hyperchromatic cytoplasm.
- High power:
Name | Staining (cytoplasm) | Quantity of cells | Cytoplasm (quantity) | Function |
(parathyroid) chief cells | intense hyperchromatic to eosinophilic (see note) | abundant | moderate | manufacture PTH |
oxyphil cells | moderate/light hyperchromatic to eosinophilic | rare | abundant | ? |
Notes:
- Cytoplasmic staining varies considerably on H&E preparations - it may vary from hyperchromatic[9] to clear to eosinophilic[10].
- Chief cells tend to stain more intensely than oxyphil cells.
Thyroid vs. parathyroid (see: parathyroid image):
- Parathyroid cytoplasm:
- Hyperchromatic.
Parathyroid vs. lymphoid tissue (see parathyroid image):
- Parathyroid:
- No germinal centres.
- Gland-like/follicular-like arrangement -- much smaller than normal follicles of
- Occasional cell with rim of clear cytoplasm (oxyphil?).
Images:
Parathyroid hyperplasia
- Parathyroid hyperplasia - classically assoc. with renal failure.
- Chief cell hyperplasia - associated with MEN I, MEN IIa.[11]
Parathryoid adenoma
MEN I:
- Parathyroid adenoma.
- Pancreatic neuroendocrine tumours.
- Pituitary adenoma.
MEN IIa/IIb (II/III):
- Parathyroid adenoma.
- Medullary thyroid carcinoma.
- Pheochromocytoma.
Benign
Solid cell nest of thyroid
General
- Embryonic remnants endodermal origin.[13]
- Incidental finding.
Microscopic
Features:[13]
- Solid or cystic cluster or variable size.
- Cuboidal-to-columnar morphology.
- Eosinophilic cytoplasm.
- Round/ovoid nuclei with finely granular chromatin.
- +/-Goblet cells (~30% of cases).[14]
Image:
DDx:[13]
- C-cell hyperplasia.
- Medullary carcinoma.
- Squamous lesions.
IHC
Features:[13]
- p63 +ve.
- -ve in clear cells.
- CEA +ve (polyconal).[14]
- +ve also in clear cells.
Nodular hyperplasia
General
- AKA goitre, AKA sporadic goitre, AKA multinodular goitre (MNG).
- Most common diagnosis in the thyroid.
- If you've seen a handful of thyroids you've seen this.
Notes:
- Large lesions may be clonal; however, this is clinically irrelevant.
Microscopic
Features:
- Follicles of variable size - key feature.
- Should be obvious at low power, i.e. ~2.5x objective.
- Nodules maybe well circumscribed (on gross), but do not have a thick fibrous capsule.
Negatives:
- No nuclear features suggestive of malignancy (at lower power).
- One should not look at high power.
- Not cellular.
Follicular adenoma
General
- Most common neoplasm of thyroid.[15]
- Encapusled lesion (surrounded by fibrous capsule).
Gross
- Thick capsule.
Notes:
- The entire capsule should be submitted.[16]
- A good start for most thyroid specimens with a thick capsule is 10 blocks.
Microsopic
Features:
- Cellular.
Negatives.
- No invasion of the capsule (see follicular thyroid carcinoma section).
- No nuclear features suggestive of papillary carcinoma.
Graves disease
General
- Often misspelled "Grave's disease".
- Autoimmune disease leading to hyperthyroidism.
- Eye problems not resolved with thyroid removal. (???)
- Higher risk of papillary thyroid carcinoma.
Gross
Features:[17]
- Enlarged 50-150 g.
- "Beefy-red" appearance, looks like raw beef.
Microscopic
Features:
- Classic:
- Hypercellular
- Patchy lymphocytes.
- Little colloid.
- Scalloping of colloid; colloid has undulating border.
- Non-specific finding.
- +/-Nuclear clearing.
- +/-Papillae (may mimic papillary thyroid carcinoma in this respect).
Notes:
- Usually has an unimpressive appearance... as it is treated, i.e. history is important.
- Nuclear clearing and papillae are usu. diffuse in Graves disease - unlike in papillary thyroid carcinoma.
Granulomatous thyoiditis
General
Microscopic
Features:[19]
Ridel thyroiditis
General
- Disease of the neck.
- Thought to be related to retroperitoneal fibrosis.
- Usually hypothyroid.
- +/-Obstructive symptoms.
Microscopic
Features:
- Fibrosis.
- Specimen often fragmented as it was difficult to remove.
DDx:
- Anaplastic carcinoma - spindle cell variant.
Hashimoto's thyroiditis
General
- Autoimmune disease leading to hypothyroidism.
- Often genetic/part of a syndrome.
Associations:[20]
- Antimicrosomal (antithyroid peroxidase) +ve.
- Antithyroglobulin +ve.
- Increased risk of B-cell lymphoma.
Microscopic
Features:
- Lymphocytic infiltrate.
- Nuclear clearing common.
- May confuse with papillary carcinoma.
- Polymorphous lymphoplasmacytic infiltrate with germinal centres.[21]
- +/-Oncocytic metaplasia.
Notes:
- Histologically often not possible to separate from "nonspecific" thyroiditis.[22]
C cell hyperplasia
General
- Screening for C cell hyperplasia/medullary thyroid carcinoma done with serum calcitonin level.[23]
Microscopic
Features:
- Definitions vary.[24]
One definition - either of the following:[23]
- >50 C-cells per low-power field (x100).
- This part of the definition suffers from LPFitis. The paper should have been rejected.
- Confined to the thyroid gland and no larger than 10 mm in greatest dimension.
Another definition:
- Invasion of the basement membrane with stromal reaction.
A third definition:
- "Several clusters of more than six C cells.
Malignant neoplasm
There are a bunch of 'em. The most common, by far, is papillary.
Papillary thyroid carcinoma
- Abbreviated PTC.
General
Medical school memory device P's:
- Palpable nodes.
- Popular (most common malignant neoplasm of the thyroid).
- Prognosis is good.
- Pre-Tx iodine scan.
- Post-Sx iodine scan.
- Psammoma bodies.
Notes:
- PTC is associated with radiation exposure.[25]
- Papillary thyroid microcarcinoma is defined as a tumour with a maximal dimension of 1.0 cm or less.[26]
Microscopic
Features:
- Nuclear changes - key feature.
- "Shrivelled nuclei"/"raisin" like nuclei, nuclei with a wavy nuclear membrane -- usu. easy to find.
- Nuclear inclusions - usu. harder to find; have high specificity.
- Nuclear grooves.
- Nuclear clearing (only on permanent section) - also known as "Orphan Annie eyes".
- Overlap of nuclei - "cells do not respect each other's borders" (easy to see at key feature at low power).
- Classically has papillae (nipple-like shape); papilla (definition): epithelium on fibrovascular core.
- Absence of papillae does not exclude diagnosis.
- Psammoma bodies.
- Circular, acellular, eosinophilic whorled bodies.
- Not necessary to make diagnosis - but very specific in the context of a specimen labeled "thyroid".
- Arise from infarction & calcification of papilla tips.[27]
Notes:
- Psammoma bodies are awesome if you see 'em, i.e. useful for arriving at the diagnosis.
- If there are no papillae structures -- you're unlikely to see psammoma bodies.
- At low power look for cellular areas/loss of follicles.
- Nuclear clearing seen in:
- Nuclear overlapping is easy to see at lower power-- should be the tip-off to look at high power for nuclear features.
- Nuclear inclusions are quite rare and not required to make the diagnosis -- but a very convincing feature if seen.
- Papillae may be seen in Graves disease.
Subtypes of papillary thyroid carcinoma
There are many.
Tall cell variant
General
- ~10% of PTC.[29]
- Often large > 6 cm.
Microscopic
Features:[30]
- 50% of cells with height 2x the width.[31][32]
- Eosinophilic cytoplasm.
- Well-defined cell borders.
- Nucleus stratified; basal location, i.e. closer to the basement membrane.
Negative:
- Nuclei not pseudostratified, if pseudostratified consider columnar cell variant.
Columnar cell variant
General
Epidemiology:
- Poor prognosis.
- Very rare.
Microscopic
Features:[34]
- Elongated nuclei (similar to colorectal adenocarcinoma) - key feature.
- +/-Pseudostratification of the nuclei (like in colorectal adenocarcinoma), differentiates from tall cell variant.
- Nuclear stratification - key feature.
- "Minimal" papillary features.
- "Tall cells".
- Clear-eosinophilic cytoplasm.
- Mitoses common.
Image: Columnar variant PTC (wiley.com).
Follicular variant
General
- May be confused with follicular carcinoma or follicular adenoma.
Microscopic
Features:
- Prominent follicles.
- Typically have less nuclear pseudoinclusions than the conventional type.
- +/-Capsule.
Cribriform-morular variant
General
- Associated with familial adenomatous polyposis (FAP).[35]
Microscopic
Features:
- Cribriform architectural pattern.
- Morules - balls of tissue.
Diffuse sclerosing variant
General
- Usu. young adults, children.
Microscopic
Features:[36]
- Papillae - usu. prominent.
- Solid areas with squamous metaplasia.
- Lymphocytes - abundant.
- Fibrosis.
DDx:
- Lymphocytic thyroiditis (esp. Hashimoto's thyroiditis).
Warthin-like variant
- Resemble Warthin tumour.
Microscopic
Features:[34]
- Eosinophilic cytoplasm.
- Lymphocytic thyroiditis.
- Papillae.
Insular carcinoma
General
Features:[37]
- Rare - approximately 5% of all thyroid carcinomas.
- Thought to be a separate tumour from papillary thyroid carcinoma and follicular thyroid carcinoma with a focal insular pattern.
- Some lump this entity with papillary carcinoma, i.e. consider it a variant of papillary thyroid carcinoma.
Microscopic
Features:[37]
- Islands of cells - key feature.
- Scant cytoplasm.
- Nuclei monomorphic and round.
DDx:[38]
- Medullary thyroid carcinoma.
- Poorly differentiated thyroid carcinoma.
Follicular thyroid carcinoma
Clinical
Medical school memory device 4 Fs:
- FNA NOT diagnosable.
- Far away mets (sometimes).
- Female predominant.
- Favourable prognosis.
Notes:
- Usu. has a hematologic spread.
- PTC usu. spread via lymphatics.
Microscopic
Features:
- Defined by either:
- Invasion through the capsule:
- Should be all the way through.[39]
- 1/2 does not count.
- Fibrous reaction does not count.
- "Above the contour" does not count.
- Should be all the way through.[39]
- Vascular invasion (all of the following):
- In a small vein (not a capillary), that is outside of the tumour mass.
- Tumour adherent to the side of the vessel.
- Tumour must be re-endothelialized.
- Invasion through the capsule:
Notes:
- Impossible to differentiate from follicular adenoma on FNA (no cytologic differences).
- Described as "over-diagnosed" ... misdiagnoses: PTC follicular variant, follicular adenoma, multinodular goitre with a thick capsule.
Medullary thyroid carcinoma
General
- Abbreviated MTC.
Medical school memory device - 3 M's:
- aMyloid.
- Median node dissection done.
- MEN IIa syndrome/MEN IIb syndrome.
- Medullary thyroid carcinoma.
- Pheochromocytoma.
- Parathyroid adenoma.
Epidemiology:
- Very rare.
- Poor prognosis.
- May be genetic (MEN IIa/b syndrome).
- Arises from C cells (which produce calcitonin).
Microscopic
Features:
- Nuclei with "neuroendocrine features".
- Small, round nuclei.
- Coarse chromatin (salt and pepper nuclei).
- Amyloid deposits - fluffy appearing acellular eosinophilic material in the cytoplasm.
- C-cell hyperplasia (associated with familial forms of MTC).
- C cells (AKA parafollicular cell): abundant cytoplasm - clear/pale.
Images:
- Medullary thyroid carcinoma (bmj.com).
- C cell hyperplasia (nature.com).
- C cell (rutgers.edu).
- Parafollicular cells (anatomyatlases.org).
IHC
Features:[40]
- Calcitonin +ve - it arises from C cells (which produce calcitonin).
- Congo-red +ve (amyloid present) - mnemonic: CRAP -- congo red amyloid protein.
- Neuroendocrine markers.
- CEA +ve (often better staining than calcitonin).[41]
EM
- Neurosecretory granules.
- Feature seen in neuroendocrine tumours.
Images: Neurosecretory granules (ucsf.edu).
Anaplastic thyroid carcinoma
Epidemiology
- Very rare.
- Horrible prognosis.
- Often presents with obstruction.
- Typically there is a history of a thyroid mass.
Microscopic
Features:
- Cytologically malignant:
- Huge NC ratio.
- Mitoses.
- +/-Necrosis.
Notes:
- May have features of other thyroid carcinomas, e.g. psammoma bodies, papillae, nuclear changes of PTC.
Image: Anaplastic thyroid carcinoma with a component of papillary thyroid carcinoma (WC).
DDx:
- Poorly differentiated carcinoma.
- Squamous cell carcinoma.
- Medullary thyroid carcinoma.
IHC
- Keratin (AE1/AE3).
- Vimentin +ve, >90%.[42]
- Thyroglobulin - rarely +ve (~15%).[42]
- CEA -ve, calcitonin -ve; to r/o medullary.
- p53 +ve.
- TTF-1 +ve.
Lymphomas of the thyroid
General
- Rare.
- Increased risk with chronic inflammatory conditions.
- Fit in the the greater category of MALT lymphoma.
Microscopic
Features:
- Lymphoepithelial lesion - key feature.
- Plasma cells.
- "Overgrowth" - thyroid parenchyma displaced by lymphocytes.
Weird stuff
Hyalinizing trabecular tumour
General
- AKA hyalinizing trabecular adenoma.
- Considered by some (e.g. SL Asa) to be a variant of papillary thyroid carcinoma.[43]
- Behaviour similar to papillary thyroid carcinoma - indolent.
Microscopic
Features:[44]
- Trabecular arrangement of cells.
- May have "curved" trabeculae.
- Extracellular space has hyaline material.
- Cytoplasm mimics hyaline material in the extracellular space.
Image:
DDx:
- Papillary thyroid carcinoma (if one believes this is a separate entity).
- Medullary thyroid carcinoma.
- Paraganglioma.[45]
IHC
- Thyroglobulin +ve.
- NSE +ve.
Hürthle cell neoplasm
- This is a general category.
- AKA oncocytic neoplasm.
DDx:
- Hürthle cell adenoma.
- Hürthle cell carcinoma.
General
- Uncommon.
Gross
- Yellow.
- Encapsulated.
Microscopic
Features:
- Oncocytes:
- Abundant eosinophilic cytoplasm.
Negatives:
- Lack nuclear features of papillary thyroid carcinoma.
- Lack features of medullary thyroid carcinoma.
DDx:[46]
- Papillary thyroid carcinoma oncocytic variant.
- Medullary thyroid carcinoma oncocytic variant.
- Others.
See also
References
- ↑ BEC. 20 October 2009.
- ↑ SR. 17 January 2011.
- ↑ 3.0 3.1 Rydlova, M.; Ludvikova, M.; Stankova, I. (Jun 2008). "Potential diagnostic markers in nodular lesions of the thyroid gland: an immunohistochemical study.". Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 152 (1): 53-9. PMID 18795075.
- ↑ Papotti, M.; Rodriguez, J.; De Pompa, R.; Bartolazzi, A.; Rosai, J. (Apr 2005). "Galectin-3 and HBME-1 expression in well-differentiated thyroid tumors with follicular architecture of uncertain malignant potential.". Mod Pathol 18 (4): 541-6. doi:10.1038/modpathol.3800321. PMID 15529186.
- ↑ http://www.medicalhistology.us/twiki/pub/Main/ChapterFourteenSlides/b56b_parathyroid_40x_he_labeled.jpg
- ↑ http://pathology.mc.duke.edu/research/Histo_course/parathyroid2.jpg
- ↑ http://www.bu.edu/histology/p/15002loa.htm
- ↑ http://dictionary.reference.com/search?q=oxyphil%20cell
- ↑ http://www.deltagen.com/target/histologyatlas/atlas_files/endocrine/parathyroid_and_thyroid_glands_20x.jpg
- ↑ http://instruction.cvhs.okstate.edu/Histology/HistologyReference/hrendo.htm
- ↑ URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970475-2. Accessed on: 29 July 2010.
- ↑ URL: http://library.med.utah.edu/WebPath/EXAM/IMGQUIZ/enfrm.html. Accessed on: 6 December 2010.
- ↑ 13.0 13.1 13.2 13.3 Reis-Filho JS, Preto A, Soares P, Ricardo S, Cameselle-Teijeiro J, Sobrinho-Simões M (January 2003). "p63 expression in solid cell nests of the thyroid: further evidence for a stem cell origin". Mod. Pathol. 16 (1): 43–8. doi:10.1097/01.MP.0000047306.72278.39. PMID 12527712. http://www.nature.com/modpathol/journal/v16/n1/full/3880708a.html.
- ↑ 14.0 14.1 Mizukami Y, Nonomura A, Michigishi T, et al. (February 1994). "Solid cell nests of the thyroid. A histologic and immunohistochemical study". Am. J. Clin. Pathol. 101 (2): 186–91. PMID 7509563.
- ↑ Thompson, Lester D. R. (2006). Endocrine Pathology: A Volume in Foundations in Diagnostic Pathology Series (1st ed.). Churchill Livingstone. pp. 51. ISBN 978-0443066856.
- ↑ SR. 17 January 2011.
- ↑ Thompson, Lester D. R. (2006). Endocrine Pathology: A Volume in Foundations in Diagnostic Pathology Series (1st ed.). Churchill Livingstone. pp. 30. ISBN 978-0443066856.
- ↑ SR. 17 January 2011.
- ↑ Mills, Stacey E; Carter, Darryl; Greenson, Joel K; Oberman, Harold A; Reuter, Victor E (2004). Sternberg's Diagnostic Surgical Pathology (4th ed.). Lippincott Williams & Wilkins. pp. 559. ISBN 978-0781740517.
- ↑ Poropatich C, Marcus D, Oertel YC (1994). "Hashimoto's thyroiditis: fine-needle aspirations of 50 asymptomatic cases". Diagn. Cytopathol. 11 (2): 141–5. PMID 7813361. http://www3.interscience.wiley.com/journal/112701408/abstract?CRETRY=1&SRETRY=0.
- ↑ Lefkowitch, Jay H. (2006). Anatomic Pathology Board Review (1st ed.). Saunders. pp. 672. ISBN 978-1416025887.
- ↑ Mills, Stacey E; Carter, Darryl; Greenson, Joel K; Oberman, Harold A; Reuter, Victor E (2004). Sternberg's Diagnostic Surgical Pathology (4th ed.). Lippincott Williams & Wilkins. pp. 560. ISBN 978-0781740517.
- ↑ 23.0 23.1 Machens A, Hoffmann F, Sekulla C, Dralle H (December 2009). "Importance of gender-specific calcitonin thresholds in screening for occult sporadic medullary thyroid cancer". Endocr. Relat. Cancer 16 (4): 1291–8. doi:10.1677/ERC-09-0136. PMID 19726541. http://erc.endocrinology-journals.org/cgi/content/full/16/4/1291.
- ↑ SR. 17 January 2011.
- ↑ Mills, Stacey E; Carter, Darryl; Greenson, Joel K; Oberman, Harold A; Reuter, Victor E (2004). Sternberg's Diagnostic Surgical Pathology (4th ed.). Lippincott Williams & Wilkins. pp. 564. ISBN 978-0781740517.
- ↑ Sethom, A.; Riahi, I.; Riahi, K.; Akkari, K.; Benzarti, S.; Miled, I.; Chebbi, MK. (Jan 2011). "[Management of thyroid microcarcinoma. Report of 13 cases].". Tunis Med 89 (1): 23-5. PMID 21267823.
- ↑ Mills, Stacey E; Carter, Darryl; Greenson, Joel K; Oberman, Harold A; Reuter, Victor E (2004). Sternberg's Diagnostic Surgical Pathology (4th ed.). Lippincott Williams & Wilkins. pp. 565. ISBN 978-0781740517.
- ↑ Mills, Stacey E; Carter, Darryl; Greenson, Joel K; Oberman, Harold A; Reuter, Victor E (2004). Sternberg's Diagnostic Surgical Pathology (4th ed.). Lippincott Williams & Wilkins. pp. 566. ISBN 978-0781740517.
- ↑ Mills, Stacey E; Carter, Darryl; Greenson, Joel K; Reuter, Victor E; Stoler, Mark H (2009). Sternberg's Diagnostic Surgical Pathology (5th ed.). Lippincott Williams & Wilkins. pp. 505. ISBN 978-0781779425.
- ↑ Urano M, Kiriyama Y, Takakuwa Y, Kuroda M (April 2009). "Tall cell variant of papillary thyroid carcinoma: Its characteristic features demonstrated by fine-needle aspiration cytology and immunohistochemical study". Diagn. Cytopathol.. doi:10.1002/dc.21086. PMID 19373912.
- ↑ http://pathologyoutlines.com/thyroid.html#tallcellvariant
- ↑ 32.0 32.1 Ghossein R, Livolsi VA (November 2008). "Papillary thyroid carcinoma tall cell variant". Thyroid 18 (11): 1179–81. doi:10.1089/thy.2008.0164. PMID 18925842.
- ↑ SR. 17 January 2011.
- ↑ 34.0 34.1 Mills, Stacey E; Carter, Darryl; Greenson, Joel K; Reuter, Victor E; Stoler, Mark H (2009). Sternberg's Diagnostic Surgical Pathology (5th ed.). Lippincott Williams & Wilkins. pp. 506. ISBN 978-0781779425.
- ↑ Groen EJ, Roos A, Muntinghe FL, et al. (September 2008). "Extra-intestinal manifestations of familial adenomatous polyposis". Ann. Surg. Oncol. 15 (9): 2439–50. doi:10.1245/s10434-008-9981-3. PMC 2518080. PMID 18612695. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2518080/?tool=pubmed.
- ↑ Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1122. ISBN 978-1416031215.
- ↑ 37.0 37.1 Rufini V, Salvatori M, Fadda G, et al. (September 2007). "Thyroid carcinomas with a variable insular component: prognostic significance of histopathologic patterns". Cancer 110 (6): 1209–17. doi:10.1002/cncr.22913. PMID 17665497.
- ↑ Endo. fellow. 17 September 2009.
- ↑ SR. 17 January 2011.
- ↑ URL: http://pathologyoutlines.com/thyroid.html#medullary. Accessed on: 17 January 2011.
- ↑ SB. 7 January 2010.
- ↑ 42.0 42.1 Ordóñez NG, El-Naggar AK, Hickey RC, Samaan NA (July 1991). "Anaplastic thyroid carcinoma. Immunocytochemical study of 32 cases". Am. J. Clin. Pathol. 96 (1): 15–24. PMID 1712540.
- ↑ Cheung CC, Boerner SL, MacMillan CM, Ramyar L, Asa SL (December 2000). "Hyalinizing trabecular tumor of the thyroid: a variant of papillary carcinoma proved by molecular genetics". Am. J. Surg. Pathol. 24 (12): 1622–6. PMID 11117782.
- ↑ URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675(06)71558-3. Accessed on: 17 January 2011.
- ↑ URL: http://path.upmc.edu/cases/case465/dx.html. Accessed on: 17 January 2011.
- ↑ Montone KT, Baloch ZW, LiVolsi VA (August 2008). "The thyroid Hürthle (oncocytic) cell and its associated pathologic conditions: a surgical pathology and cytopathology review". Arch. Pathol. Lab. Med. 132 (8): 1241–50. PMID 18684023.