Medullary thyroid carcinoma

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Medullary thyroid carcinoma
Diagnosis in short

Medullary thyroid carcinoma. H&E stain.
Site thyroid gland

Syndromes multiple endocrine neoplasia IIa, multiple endocrine neoplasia IIb

Prevalence uncommon
Prognosis poor

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:

Epidemiology:

  • Very rare.
  • Poor prognosis.
  • May be genetic (MEN IIa/b syndrome).
  • Arises from C cells (which produce calcitonin).

Syndromic tumours - typically:[1]

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:

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. 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.
  2. 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.
  3. URL: http://pathologyoutlines.com/thyroid.html#medullary. Accessed on: 17 January 2011.
  4. SB. 7 January 2010.
  5. 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.