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Mutation of KIT in cellular extraskeletal myxoid chondrosarcoma: a case report and literature review
Chen Wang1, Zhi-Jie You2, Xiao-Yan Chen3
1Department of Pathology, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, NO. 134, East Street, Gulou District, 350001, Fuzhou, Fujian Province, China. l-morning@163.com.
Background:
Extraskeletal myxoid chondrosarcomas (EMCs) are solid tumors that have been genetically and biologically characterized. Only a few studies have discussed the role of the KIT gene or CD117 expression in EMCs, identified by immunohistochemical (IHC) staining. Herein, we present a novel case of cellular EMC exhibiting an EWSR1-NR4A3 fusion, KIT exon 13 mutations and strong diffuse expression of CD117.
Case Presentation:
A 69-year-old man presented with a fist-sized tumor on his left shoulder. CT revealed a tumor in the left thoracic and dorsal muscle space. The tumor was completely resected. Histologically, the tumor cells had a nodular structure and infiltrated the peripheral fat and muscle tissues. The tumor cells were uniform in size with round nuclei, well-defined nucleoli and eosinophilic cytoplasm. Immunohistochemically, the tumor cells were positive for CD117, vimentin, CD56 and NSE and focally expressed desmin; the cells were negative for myogenin, S-100, SYN, INSM1, CD34, STAT6, INI-1, Brachyury, ERG, TLE1, AE1/AE3, WT-1, CD99 and SMA. NGS revealed an EWSR1-NR4A3 fusion and KIT exon 13 mutations. The patient had no further treatment after surgery, and no recurrence or metastasis occurred during the ~ 10 month follow-up period.
Conclusions:
Molecular detection is an indispensable technique for diagnosing cellular EMCs. The KIT mutations noted in this case report may offer fresh insights into EMCs treatment options.
Insights
This study reports a rare cellular extraskeletal myxoid chondrosarcoma (EMC) with EWSR1-NR4A3 fusion and KIT mutations. These findings highlight the importance of molecular diagnostics and may inform future treatment strategies for EMC.
Area of Science:
- Oncology
- Molecular Pathology
- Genetics
Background:
- Extraskeletal myxoid chondrosarcomas (EMCs) are rare soft tissue tumors.
- The genetic landscape and diagnostic markers for EMCs are not fully understood.
- Limited research exists on the role of the KIT gene and CD117 expression in EMCs.
Observation:
- A 69-year-old male presented with a large shoulder tumor.
- Histopathology revealed a cellular EMC with specific cellular morphology.
- Immunohistochemistry showed positivity for CD117, vimentin, CD56, and NSE.
Findings:
- Next-generation sequencing identified an EWSR1-NR4A3 fusion and KIT exon 13 mutations.
- The tumor exhibited strong and diffuse CD117 expression.
- The patient achieved a favorable outcome with complete surgical resection and no recurrence at 10 months.
Implications:
- Molecular detection, including genetic fusion and mutation analysis, is crucial for diagnosing cellular EMC.
- The identified KIT mutations may represent a therapeutic target for EMCs.
- This case expands the understanding of EMC molecular heterogeneity and potential treatment avenues.
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