Difference between revisions of "Mucoepidermoid carcinoma"

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#redirect [[Salivary_glands#Mucoepidermoid_carcinoma]]
'''Mucoepidermoid carcinoma''', abbreviated ''MEC'', the is the most common malignant neoplasm of the [[salivary gland]].
 
==General==
*Most common malignant neoplasm of salivary gland in all age groups.<ref>URL: [http://path.upmc.edu/cases/case715/dx.html http://path.upmc.edu/cases/case715/dx.html]. Accessed on: 2 February 2012.</ref>
*Female:male ~= 3:2.
*Site: parotid > submandibular.
 
==Gross==
*Cystic or solid, usu. a mix of both.
 
==Microscopic==
Features:
*Architecture:<ref>URL: [http://moon.ouhsc.edu/kfung/jty1/opaq/PathQuiz/D2A001-PQ01-M.htm http://moon.ouhsc.edu/kfung/jty1/opaq/PathQuiz/D2A001-PQ01-M.htm]. Accessed on: 19 October 2010.</ref>
**Cystic (low grade).
**Solid (high grade).
*Mucous cells with abundant fluffy cytoplasm and large mucin vacuoles - '''key feature'''.
**Nucleus distorted by mucin vacuole.
**Mucous cell may be scarce - more difficult to diagnose.
*Epidermoid cells:
**Non-keratinized, polygonal squamoid cell with clear or oncocytic cytoplasm.
***Clear cells contain glycogen ([[PAS]] +ve, [[PAS-D]] -ve).
 
Notes:
*The classic description - composed of 3 cell types: epidermoid, intermediate, and mucin producing.<ref>{{Cite journal  | last1 = Lennerz | first1 = JK. | last2 = Perry | first2 = A. | last3 = Mills | first3 = JC. | last4 = Huettner | first4 = PC. | last5 = Pfeifer | first5 = JD. | title = Mucoepidermoid carcinoma of the cervix: another tumor with the t(11;19)-associated CRTC1-MAML2 gene fusion. | journal = Am J Surg Pathol | volume = 33 | issue = 6 | pages = 835-43 | month = Jun | year = 2009 | doi = 10.1097/PAS.0b013e318190cf5b | PMID = 19092631 }}</ref>
**"Intermediate cells" are described in textbooks. Weinreb thinks they are a pretty much a myth.<ref name=IW_10jan2011>IW. 10 January 2011.</ref>
*Mucin vacuoles may be rare; in a superficial glance -- it may mimic [[squamous cell carcinoma]].
*The thought of high-grade MEC should prompt consideration of squamous cell carcinoma.
 
===Images===
<gallery>
Image:Mucoepidermoid_carcinoma_%282%29_HE_stain.jpg | Mucoepidermoid carcinoma 2. (WC)
Image:Mucoepidermoid_carcinoma_%283%29_HE_stain.jpg | Mucoepidermoid carcinoma 3. (WC)
Image:Mucoepidermoid_carcinoma_-_2_-_intermed_mag.jpg | Mucoepidermoid carcinoma - 2 - intermed. mag. (WC/Nephron)
Image:Mucoepidermoid_carcinoma_-_2_-_high_mag.jpg | Mucoepidermoid carcinoma - 2 - high mag. (WC/Nephron)
Image:Mucoepidermoid_carcinoma_-_2a_-_very_high_mag.jpg | Mucoepidermoid carcinoma - 2 - very high mag. (WC/Nephron)
</gallery>
www:
*[http://moon.ouhsc.edu/kfung/jty1/opaq/PathQuiz/D2A001-PQ01-M.htm Mucoepidermoid carcinoma (ouhsc.edu)].
 
===Subtypes===
*Conventional.
*Oncocytic.
**Definition: composed of 50% oncocytes.
**Good outcome.<ref name=pmid18971778>{{cite journal |author=Weinreb I, Seethala RR, Perez-Ordoñez B, Chetty R, Hoschar AP, Hunt JL |title=Oncocytic mucoepidermoid carcinoma: clinicopathologic description in a series of 12 cases |journal=Am. J. Surg. Pathol. |volume=33 |issue=3 |pages=409–16 |year=2009 |month=March |pmid=18971778 |doi=10.1097/PAS.0b013e318184b36d |url=}}</ref>
*Clear cell.
*Unicystic (cystadenocarcinoma).
**Based on the gross. (???)
*Sclerosing MEC +/- eosinophilia.
**Rare.
 
===Grading===
General:
*Two competing system exist:
**AFIP.<ref name=pmid9529011>{{cite journal |author=Goode RK, Auclair PL, Ellis GL |title=Mucoepidermoid carcinoma of the major salivary glands: clinical and histopathologic analysis of 234 cases with evaluation of grading criteria |journal=Cancer |volume=82 |issue=7 |pages=1217–24 |year=1998 |month=April |pmid=9529011 |doi= |url=}}</ref>
**Brandwein.<ref name=pmid11420454>{{cite journal |author=Brandwein MS, Ivanov K, Wallace DI, ''et al.'' |title=Mucoepidermoid carcinoma: a clinicopathologic study of 80 patients with special reference to histological grading |journal=Am. J. Surg. Pathol. |volume=25 |issue=7 |pages=835–45 |year=2001 |month=July |pmid=11420454 |doi= |url=}}</ref>
 
Notes:
*Both systems have their pros and cons.
*Weinreb uses the AFIP system with a slight modification.
 
====AFIP====
#Low cystic content (<20%) - 2 points.
#[[Perineural invasion]] - 2 points.
#[[Necrosis]] - 3 points.
#Mitoses > 4 per 10 HPFs (HPF not defined in paper - see [[HPFitis]]) - 3 points.
#Anaplasia - 4 points.
 
Scoring:
*Low grade = 0-4 points.
*Intermediate grade = 5-6 points.
*High grade = 7+ points.
 
=====Weinreb modification=====
Weinreb looks for the following:
*Tumour invades in small nests/islands - 2 points.
**If applicable, the two points are added to the AFIP score.
**The tumour is graded using the AFIP (scoring) cut points -- see above.
 
Notes:
*It seems pointless to memorize this but it is occasionally asked on exams.
**How to remember: think of the Nottingham grading system (architecture, mitoses, nuclear grade) + necrosis + LVI.
 
==Stains==
Mucous cells:
*Alcian blue +ve.
*Mucicarcmine +ve.
 
==Molecular==
*t(11;19)(q21;p13) -- MECT1-MAML2 fusion.<ref name=pmid12539049>{{cite journal |author=Tonon G, Modi S, Wu L, ''et al.'' |title=t(11;19)(q21;p13) translocation in mucoepidermoid carcinoma creates a novel fusion product that disrupts a Notch signaling pathway |journal=Nat. Genet. |volume=33 |issue=2 |pages=208–13 |year=2003 |month=February |pmid=12539049 |doi=10.1038/ng1083 |url=}}</ref><ref name=pmid20588178>{{cite journal |author=Seethala RR, Dacic S, Cieply K, Kelly LM, Nikiforova MN |title=A reappraisal of the MECT1/MAML2 translocation in salivary mucoepidermoid carcinomas |journal=Am. J. Surg. Pathol. |volume=34 |issue=8 |pages=1106–21 |year=2010 |month=August |pmid=20588178 |doi=10.1097/PAS.0b013e3181de3021 |url=}}</ref>
**Present in ~65% of MECs.
**Presence assoc. with low-grade MEC (vs. high-grade MEC) & favourable prognosis.
**Not seen in tumours that are in the DDx of MEC.
 
==See also==
*[[Salivary glands]].
 
==References==
{{Reflist|2}}


[[Category:Diagnosis]]
[[Category:Diagnosis]]
[[Category:Salivary glands]]

Revision as of 01:55, 27 October 2013

Mucoepidermoid carcinoma, abbreviated MEC, the is the most common malignant neoplasm of the salivary gland.

General

  • Most common malignant neoplasm of salivary gland in all age groups.[1]
  • Female:male ~= 3:2.
  • Site: parotid > submandibular.

Gross

  • Cystic or solid, usu. a mix of both.

Microscopic

Features:

  • Architecture:[2]
    • Cystic (low grade).
    • Solid (high grade).
  • Mucous cells with abundant fluffy cytoplasm and large mucin vacuoles - key feature.
    • Nucleus distorted by mucin vacuole.
    • Mucous cell may be scarce - more difficult to diagnose.
  • Epidermoid cells:
    • Non-keratinized, polygonal squamoid cell with clear or oncocytic cytoplasm.
      • Clear cells contain glycogen (PAS +ve, PAS-D -ve).

Notes:

  • The classic description - composed of 3 cell types: epidermoid, intermediate, and mucin producing.[3]
    • "Intermediate cells" are described in textbooks. Weinreb thinks they are a pretty much a myth.[4]
  • Mucin vacuoles may be rare; in a superficial glance -- it may mimic squamous cell carcinoma.
  • The thought of high-grade MEC should prompt consideration of squamous cell carcinoma.

Images

  • Mucoepidermoid carcinoma 2. (WC)

  • Mucoepidermoid carcinoma 3. (WC)

  • Mucoepidermoid carcinoma - 2 - intermed. mag. (WC/Nephron)

  • Mucoepidermoid carcinoma - 2 - high mag. (WC/Nephron)

  • Mucoepidermoid carcinoma - 2 - very high mag. (WC/Nephron)

www:

Subtypes

  • Conventional.
  • Oncocytic.
    • Definition: composed of 50% oncocytes.
    • Good outcome.[5]
  • Clear cell.
  • Unicystic (cystadenocarcinoma).
    • Based on the gross. (???)
  • Sclerosing MEC +/- eosinophilia.
    • Rare.

Grading

General:

  • Two competing system exist:

Notes:

  • Both systems have their pros and cons.
  • Weinreb uses the AFIP system with a slight modification.

AFIP

  1. Low cystic content (<20%) - 2 points.
  2. Perineural invasion - 2 points.
  3. Necrosis - 3 points.
  4. Mitoses > 4 per 10 HPFs (HPF not defined in paper - see HPFitis) - 3 points.
  5. Anaplasia - 4 points.

Scoring:

  • Low grade = 0-4 points.
  • Intermediate grade = 5-6 points.
  • High grade = 7+ points.
Weinreb modification

Weinreb looks for the following:

  • Tumour invades in small nests/islands - 2 points.
    • If applicable, the two points are added to the AFIP score.
    • The tumour is graded using the AFIP (scoring) cut points -- see above.

Notes:

  • It seems pointless to memorize this but it is occasionally asked on exams.
    • How to remember: think of the Nottingham grading system (architecture, mitoses, nuclear grade) + necrosis + LVI.

Stains

Mucous cells:

  • Alcian blue +ve.
  • Mucicarcmine +ve.

Molecular

  • t(11;19)(q21;p13) -- MECT1-MAML2 fusion.[8][9]
    • Present in ~65% of MECs.
    • Presence assoc. with low-grade MEC (vs. high-grade MEC) & favourable prognosis.
    • Not seen in tumours that are in the DDx of MEC.

See also

References

  1. ↑ URL: http://path.upmc.edu/cases/case715/dx.html. Accessed on: 2 February 2012.
  2. ↑ URL: http://moon.ouhsc.edu/kfung/jty1/opaq/PathQuiz/D2A001-PQ01-M.htm. Accessed on: 19 October 2010.
  3. ↑ Lennerz, JK.; Perry, A.; Mills, JC.; Huettner, PC.; Pfeifer, JD. (Jun 2009). "Mucoepidermoid carcinoma of the cervix: another tumor with the t(11;19)-associated CRTC1-MAML2 gene fusion.". Am J Surg Pathol 33 (6): 835-43. doi:10.1097/PAS.0b013e318190cf5b. PMID 19092631.
  4. ↑ IW. 10 January 2011.
  5. ↑ Weinreb I, Seethala RR, Perez-Ordoñez B, Chetty R, Hoschar AP, Hunt JL (March 2009). "Oncocytic mucoepidermoid carcinoma: clinicopathologic description in a series of 12 cases". Am. J. Surg. Pathol. 33 (3): 409–16. doi:10.1097/PAS.0b013e318184b36d. PMID 18971778.
  6. ↑ Goode RK, Auclair PL, Ellis GL (April 1998). "Mucoepidermoid carcinoma of the major salivary glands: clinical and histopathologic analysis of 234 cases with evaluation of grading criteria". Cancer 82 (7): 1217–24. PMID 9529011.
  7. ↑ Brandwein MS, Ivanov K, Wallace DI, et al. (July 2001). "Mucoepidermoid carcinoma: a clinicopathologic study of 80 patients with special reference to histological grading". Am. J. Surg. Pathol. 25 (7): 835–45. PMID 11420454.
  8. ↑ Tonon G, Modi S, Wu L, et al. (February 2003). "t(11;19)(q21;p13) translocation in mucoepidermoid carcinoma creates a novel fusion product that disrupts a Notch signaling pathway". Nat. Genet. 33 (2): 208–13. doi:10.1038/ng1083. PMID 12539049.
  9. ↑ Seethala RR, Dacic S, Cieply K, Kelly LM, Nikiforova MN (August 2010). "A reappraisal of the MECT1/MAML2 translocation in salivary mucoepidermoid carcinomas". Am. J. Surg. Pathol. 34 (8): 1106–21. doi:10.1097/PAS.0b013e3181de3021. PMID 20588178.
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