Indian Journal of Pathology and Microbiology

CASE REPORT
Year
: 2012  |  Volume : 55  |  Issue : 4  |  Page : 519--520

Ectomesenchymal chondromyxoid tumor of tongue


Shan-Yin Tsai1, Kung-Chao Chang2, Hung-Wen Tsai2, Ying-Tai Jin DDS3,  
1 Department of Pathology, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung, Taiwan
2 Department of Pathology, National Cheng Kung University Hospital, Tainan City, Taiwan
3 Department of Pathology, Taiwan Adventist Hospital, Taipei, Taiwan

Correspondence Address:
Ying-Tai Jin DDS
Department of Pathology, Taiwan Adventist Hospital, No. 424, Sec. 2, Bade Rd. Songshan District, Taipei City 10556
Taiwan

Abstract

Ectomesenchymal chondromyxoid tumor (ECMT) is a rare entity of the dorsal tongue first described in 1995. Herein, we report a rare case of lingual ECMT in a 41-year-old man. Patient presented with an asymptomatic, small nodule (0.5 cm in diameter) in the anterior tongue. The pathological findings showed uni-lobular proliferation of fusiform cells, arranged in net-like sheets or swirls, in a chondromyxoid background. The tumor cells were immunoreactive for S-100 and glial fibrillary acidic protein (GFAP), but negative for epithelial markers. Familiarity with this entity helps pathologists make a correct diagnosis.



How to cite this article:
Tsai SY, Chang KC, Tsai HW, DDS YTJ. Ectomesenchymal chondromyxoid tumor of tongue.Indian J Pathol Microbiol 2012;55:519-520


How to cite this URL:
Tsai SY, Chang KC, Tsai HW, DDS YTJ. Ectomesenchymal chondromyxoid tumor of tongue. Indian J Pathol Microbiol [serial online] 2012 [cited 2020 Oct 25 ];55:519-520
Available from: https://www.ijpmonline.org/text.asp?2012/55/4/519/107796


Full Text

 Introduction



Ectomesenchymal chondromyxoid tumor (ECMT) of tongue is a new entity described by Smith in 1995. [1] Most of the cases showed a single asymptomatic and slow growing nodule in the anterior dorsal tongue. Immunohistochemically, the tumor cells were typically positive for glial fibrillary acidic protein (GFAP) and cytokeratin, variably positive for S100 and smooth muscle actin (SMA), but negative for desmin and epithelial membrane antigen (EMA). The differential diagnoses may include reactive myxoid lesions, cellular myxoma, extraskeletal myxoid chondrosarcoma, myxoid neurofibroma, neurothekeoma, and myoepithelioma. Exact diagnosis may be difficult on a small biopsy specimen. We report a rare case of lingual ECMT in a 41-year-old man. The clinical presentations and pathologic features was presented, which are useful for pathologists and clinicians in daily practice.

 Case Report



A 41-year-old man noted a small nodule in the anterior tongue for 2 weeks. This nodule was asymptomatic and grew slowly. An excisional biopsy was performed. Grossly, this submucosal lesion, measuring 0.5 cm in diameter, was elastic and solid with an intact overlying mucosa. Microscopically, it was a nonencapsulated but well-circumscribed tumor with a uni-lobular appearance [Figure 1]a. The tumor cells were ovoid or fusiform and arranged in net-like sheets, or swirls in a chondromyxoid background [Figure 1]b. Mild cellular atypia was focally found [Figure 1]c. Mitotic activity and necrotic focus were absent. Immunohistochemically, the tumor cells showed diffuse and strong immunostaining for GFAP [Figure 1]d and S100 [Figure 1]e, but negative stained for other cytokeratin markers (AE1 / 3 [Figure 1]f, CK7, CK20, 34βE12, CAM5.2), actin, p63, CD117, myogenin or human melanoma black 45 (HMB45). Taken together, an ECMT of tongue was diagnosed. The patient remained disease-free for 2 years and 7 months after excision.{Figure 1}

 Discussion



The ECMT is a rare neoplasm occurring in a wide age range without gender predilection. [1] The characteristic clinical presentation is a painless small nodule (mean size, 1.2 cm) over the dorsal tongue with gradual enlargement or in stationary. [2] The tumor is nonencapsulated but well-circumscribed with or without focal infiltration into the regional striated muscles. It is characterized by lobular proliferation of fusiform cells, arranged in net-like sheets or swirls, with variable amounts of cellular, myxoid and chondroid background. [1],[3] Focal nuclear atypia may be present and mitotic activity is uncommon. However, focal infiltration of skeletal muscles or nuclear pleomorphism should raise the concern of regular follow-up after surgical treatment. [1],[2],[4] Necrosis is not the feature. [5] Ultra structurally, the feature of myoepithelial cells such as subplasmalemmal densities with desmosomes and microfilaments were commonly seen in ECMT but absent in myoepithelial tumor. [1],[6]

Immunohistochemically, the tumor is typically positive for vimentin and myoepithelial cell markers (GFAP and S100), but variable expression of cytokeratin and the neurogenic marker, Leu-7. [2],[7] The most important pathological differential diagnoses are myoepithelioma, neurothekeoma, myxoid neurofibroma, and extraskeletal myxoid chondrosarcoma. Neurofibroma characteristically shows the wavy nuclei and lacks of chondroid areas. Extraskeletal myxoid chondrosarcoma typically arises in proximal extremities, and very rarely occurs in oral cavity. It features multi-nodules of oval, spindle or epithelioid cells in a chondromyxoid background and lacks GFAP staining. Myoepithelioma typically exhibits variable cellular patterns, including epithelioid, spindle, plasmacytoid, and clear cells. [4] Myoepithelioma most frequently shows a growth of spindle cells arranged in a fascicular pattern, which is not a feature of ECMT. [1] Myoepithelioma and ECMT share similar immunohistochemical profiles. They differ only by more consistent staining for cytokeratins and variable expression of GFAP in myoepithelioma, and consistent staining for GFAP and variable expression for cytokeratins in ECMT.

The histogenesis of ECMT remains elusive. The possible cell origins may include uncommitted ectomesenchymal cell from neural crest of the first brachial arch and myoepithelial cells of ectopic salivary gland primordial. [1] The former hypothesis is based on the frequent tumor location of anterior tongue in which the original tumor cells develop from the neural crest of the first brachial arch and bear multipotentiality to differentiate into myxoid and cartilaginous cells with an immunophenotype of mesenchymal and neurogenic features. The latter hypothesis is based on the similar morphology and immunophenotype between myoepithelioma and ECMT. Ectopia of salivary gland primordial during embryogenesis is thought to be the possible tumorigenetic event since lingual salivary glands are normally localized in the posterior dorsolateral tongue and absent in the anterior tongue.

The suggested treatment modality is complete excision. Although the majority of cases were uneventful after simple excision, those cases with muscle infiltration are often excised incompletely with approximately 7% recurrence rate. [8] These atypical features make the correct diagnosis more pivotal.

Conclusively, ECMT of tongue behave generally in a benign course, although focal cellular atypia and recurrence in a small subset of cases may occur.

References

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