Oral cavity & oropharynx

Soft tissue tumors & proliferations

Ectomesenchymal chondromyxoid tumor


Editorial Board Member: Bin Xu, M.D., Ph.D.
Deputy Editor-in-Chief: Kelly Magliocca, D.D.S., M.P.H.
Molly Housley Smith, D.M.D.

Last author update: 26 August 2022
Last staff update: 26 August 2022

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PubMed Search: Ectomesenchymal chondromyxoid tumor

Molly Housley Smith, D.M.D.
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Cite this page: Smith MH. Ectomesenchymal chondromyxoid tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/oralcavityect.html. Accessed December 9th, 2022.
Definition / general
  • Rare, benign soft tissue tumor with striking predilection for the anterior dorsal tongue
  • First named by Smith et al. in 1995 (Am J Surg Pathol 1995;19:519)
Essential features
  • Most are found on the anterior dorsal tongue
  • Fewer than 120 well documented cases have been reported
  • Histopathologically demonstrates a well defined, often multilobulated tumor with ovoid, round, fusiform or polygonal cells within a sometimes myxoid, chondromyxoid or mucoid background
  • Reticular arrangement of cells is often noted
  • Characterized by RREB1::MRTFB (previously MKL2) fusion in 90% of cases (Am J Surg Pathol 2018;42:1297)
  • Conservative excision recommended; < 10% have recurred
Terminology
ICD coding
  • ICD-10: D10.1 - benign neoplasm of tongue
Epidemiology
Sites
Etiology
Clinical features
Diagnosis
  • Diagnosis is made on histopathological examination
Radiology description
Radiology images

Images hosted on other servers:

Cystic appearing mass

T1 weighted image, MRI

T2 weighted image, MRI

Prognostic factors
Case reports
Treatment
Clinical images

Images hosted on other servers:

Submucosal nodule

Gross description
Gross images

Images hosted on other servers:

Well circumscribed, tan, hemorrhagic mass

Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Molly Housley Smith, D.M.D.
Prominent hemorrhagic areas

Prominent hemorrhagic areas

Entrapment within muscle

Entrapment within muscle

Focal papillary growth pattern

Focal papillary growth pattern

Chondromyxoid stroma

Chondromyxoid stroma

Hemosiderin breakdown products

Hemosiderin breakdown products


Sheets of ovoid cells

Sheets of ovoid cells

Reticular pattern

Reticular pattern

Chondromyxoid stroma

Chondromyxoid stroma

Ovoid nuclei

Ovoid nuclei

GFAP

GFAP

Virtual slides

Images hosted on other servers:

Multilobulated tumor

Cytology description
Positive stains
Negative stains
  • EMA typically negative
Electron microscopy description
Molecular / cytogenetics description
  • RREB1::MRTFB (previously MKL2) gene fusion (RNA sequencing and FISH) (Am J Surg Pathol 2018;42:1297)
  • EWSR1::CREM fusion product found in 1/21 cases and 3/11 cases showed EWSR1 rearrangement on FISH (Am J Surg Pathol 2018;42:1297, Histopathology 2016;69:607)
    • Unclear at this point whether EWSR1 rearranged ectomesenchymal chondromyxoid tumors represent a separate entity or part of the spectrum of ectomesenchymal chondromyxoid tumors
Molecular / cytogenetics images

Images hosted on other servers:

FISH rearrangement of RREB1 and MRTFB

Sample pathology report
  • Anterior tongue, excision:
    • Ectomesenchymal chondromyxoid tumor
Differential diagnosis
Board review style question #1
Ectomesenchymal chondromyxoid tumor Ectomesenchymal chondromyxoid tumor


The following tumor is found in the anterior dorsal tongue. Lesional cells are strongly and diffusely positive for GFAP and S100 protein. What is the diagnosis?

  1. Ectomesenchymal chondromyxoid tumor
  2. Glomus tumor
  3. Granular cell tumor
  4. Pleomorphic adenoma
Board review style answer #1
A. Ectomesenchymal chondromyxoid tumor. This tumor is well defined and comprised of ovoid cells set within a mucoid background.

B. While glomus tumors may show a similar morphology, the immunohistochemical profile is not compatible with glomus tumor.
C. While the dorsal tongue is a common location for granular cell tumor and S100 is positive, the morphology of the cells is inconsistent with granular cell tumor.
D. While the histomorphology is highly suggestive of pleomorphic adenoma, pleomorphic adenomas do not occur on the anterior dorsal tongue due to the lack of salivary glands in the area.

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Reference: Ectomesenchymal chondromyxoid tumor
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