Medullary thyroid carcinoma
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Medullary thyroid carcinoma, abbreviated MTC, is an uncommon epithelial malignancy of the thyroid gland that may be syndromic.
General
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).
Syndromic tumours - typically:[1]
- Present in 30s or 40s.
- +/-Multifocal.
- +/-Bilateral.
- C-cell hyperplasia.
Gross
Features:[1]
- Usu. well-circumscribed.
- White, gray or yellow.
- Gritty.
- Firm.
Image:
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 - seen with familial forms of MTC.
- C cells (AKA parafollicular cell): abundant cytoplasm - clear/pale.
Note:
- The amyloid is formed from calcitonin.[2]
Images
www:
- Medullary thyroid carcinoma (bmj.com).
- C cell hyperplasia (nature.com).
- C cell (rutgers.edu).
- Parafollicular cells (anatomyatlases.org).
MTC - low mag. (WC)
MTC - high mag. (WC)
MTC and amyloid - high mag. (WC)
IHC
Features:[3]
- 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).[4]
- Thyroglobulin usu. -ve.[5]
EM
- Neurosecretory granules.
- Feature seen in neuroendocrine tumours.
Images: Neurosecretory granules (ucsf.edu).
See also
References
- ↑ 1.0 1.1 Nosé, V. (Apr 2011). "Familial thyroid cancer: a review.". Mod Pathol 24 Suppl 2: S19-33. doi:10.1038/modpathol.2010.147. PMID 21455198.
- ↑ Khurana, R.; Agarwal, A.; Bajpai, VK.; Verma, N.; Sharma, AK.; Gupta, RP.; Madhusudan, KP. (Dec 2004). "Unraveling the amyloid associated with human medullary thyroid carcinoma.". Endocrinology 145 (12): 5465-70. doi:10.1210/en.2004-0780. PMID 15459123.
- ↑ URL: http://pathologyoutlines.com/thyroid.html#medullary. Accessed on: 17 January 2011.
- ↑ SB. 7 January 2010.
- ↑ de Micco, C.; Chapel, F.; Dor, AM.; Garcia, S.; Ruf, J.; Carayon, P.; Henry, JF.; Lebreuil, G. (Mar 1993). "Thyroglobulin in medullary thyroid carcinoma: immunohistochemical study with polyclonal and monoclonal antibodies.". Hum Pathol 24 (3): 256-62. PMID 8454270.