Skin nonmelanocytic tumor

Carcinoma (nonadnexal)

Mucoepidermoid carcinoma



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PubMed Search: Mucoepidermoid carcinoma [title] skin

Ghassan A. Tranesh, M.D.
Hong Qu, M.D.
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Cite this page: Tranesh GA, Qu H. Mucoepidermoid carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumornonmelanocyticmuc.html. Accessed January 29th, 2023.
Definition / general
Mucoepidermoid carcinoma
  • Very rare in skin (~30 cases reported)
  • Probable sweat gland origin
  • Resembles similar tumor of salivary gland
  • Usually low to intermediate grade, some higher grade tumors perhaps better classified as adenosquamous carcinoma

Adenosquamous carcinoma
Sites
Adenosquamous carcinoma
  • Frequent confusion in the literature regarding this entity in the head and neck and high grade mucoepidermoid carcinoma (Int J Clin Exp Pathol 2014;7:1809)
  • More common in organs where adenocarcinoma arises frequently, including stomach, intestines and uterus (Oncol Lett 2014;7:1941)
Pathophysiology / etiology
Adenosquamous carcinoma
  • Although its pathogenesis is largely unknown, 4 hypotheses have been proposed:
    • Malignant transformation of both squamous and glandular-like cells originating from pleiotropic epithelial stem cells
    • Tumorigenesis of squamous metaplasia in columnar epithelium
    • Transdifferentiation of adenocarcinoma to squamous cell carcinoma
    • Coexistence of both carcinomas (World J Surg Oncol 2013;11:124)
Diagnosis
Adenosquamous carcinoma
  • Neoplasm composed of an admixture or separate areas of squamous cell carcinoma and adenocarcinoma
  • Criteria for squamous cell carcinoma component are 2 or more of these features:
    • Intercellular bridging
    • Keratin pearl formation
    • Parakeratotic differentiation
    • Individual cell keratinization
    • Cellular arrangement showing a pavementing or mosaic pattern
  • Criterion for adenocarcinoma component is demonstration of intracytoplasmic mucin
  • World Health Organization Classification does not require intracytoplasmic mucin for diagnosis of adenocarcinoma in the presence of true glandular formation (Int J Clin Exp Pathol 2014;7:1809)
Case reports
Mucoepidermoid carcinoma
Adenosquamous carcinoma
Treatment
Adenosquamous carcinoma
  • Surgical excision or Mohs microsurgery are common treatment options (Head Neck Pathol 2011;5:108)
  • Locoregional recurrence is not uncommon
Clinical images

Images hosted on other servers:

Adenosquamous carcinoma

Fig 3: recurrent tumor of shoulder

Various images

Gross description
Mucoepidermoid carcinoma
  • Up to 0.6 cm, ulcerated and nonencapsulated
  • Flesh colored nodules, painless

Adenosquamous carcinoma
  • White nodular infiltrate into subcutaneous tissue
Gross images

Images hosted on other servers:

Mucoepidermoid carcinoma

High grade

Microscopic (histologic) description
Mucoepidermoid carcinoma
  • Circumscribed tumor, may not be attached to surface
  • Multilobulated nodulocystic tumor extending throughout dermis, exhibiting glandular and squamoid differentiation
  • Dermal lobules or cystic growth of low grade epidermoid, intermediate, mucinous cells and clear cells
  • Cribiform nests of epidermoid cells contain glandular spaces with mucin
  • Nuclei are mildly atypical and contain scattered mitotic figures
  • Peritumoral fibrosis is common
  • May have focal perineural invasion

Adenosquamous carcinoma
  • Infiltrative islands of squamous cell carcinoma with admixed mucin-containing glandular structures, adenomatous changes and acinar formation
  • Glandular structures lined by low columnar epithelium, sometimes lined by an eosinophilic cuticle (ductular differentiation)
  • Perineural invasion relatively common (Arch Dermatol 2009;145:1152)
Microscopic (histologic) images

Images hosted on other servers:

Mucoepidermoid carcinoma

Site unknown

Salivary gland Alcian blue-PAS

Salivary gland



Adenosquamous carcinoma

Fig 1: infiltrative nests
and keratinizing
cysts are admixed with
glandular elements

Fig 2: CK903 (high molecular
weight keratin) stains the
tumor, CEA highlights
glandular differentiation

Cytology images

Images hosted on other servers:

Mucoepidermoid carcinoma

Salivary gland

Positive stains
Mucoepidermoid carcinoma
Adenosquamous carcinoma
Negative stains
Mucoepidermoid carcinoma
Molecular / cytogenetics description
Mucoepidermoid carcinoma
  • CRTC1 rearrangements have been detected in cutaneous MEC (like salivary gland MEC) but translocation t(11,19) or MAML2 rearrangements not seen (unlike salivary gland MEC) (Br J Dermatol 2009;161:925)
Differential diagnosis
Mucoepidermoid carcinoma
  • Adenosquamous carcinoma:
    • High grade tumor, often involves epidermis, adenocarcinoma component is well differentiated
  • Metastatic salivary gland tumor:
    • Usually high grade
  • Mucinous metaplasia

Adenosquamous carcinoma
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