Extraskeletal myxoid chondrosarcoma of the masticator space in a pediatric patient

Abstract

Extraskeletal myxoid chondrosarcoma (EMC) is a malignant soft-tissue neoplasm rarely described in the head and neck region of children and adolescents. We describe a case of EMC affecting the masticator space and a literature review. A 13-year-old boy who presented a large painless, diffuse mass causing progressive midfacial asymmetry of 6 months duration. Histopathological evaluation revealed a multinodular lesion, containing scattered round vacuolated tumor cells dispersed in an abundant myxoid stroma, separated by fibrous septae. Immunohistochemical analysis revealed positivity for vimentin, neuron-specific enolase, and chromogranin. The Ki-67 labelling index was 42%. The patient was treated surgically with tumor resection followed by adjuvant local radiotherapy. The patient died 1 year after initial diagnosis due to locoregional tumor dissemination. EMC should be considered in the differential diagnosis of myxoid neoplasms in the head and neck region. Key words:Extraskeletal myxoid chondrosarcoma, masticator space, parapharyngeal space, immunohistochemistry, children.

Extraskeletal myxoid chondrosarcoma of the gingival: a rare case report and review of the literature

“…Approximately 20% of the cases are located in the trunk, mainly in skeletal muscles, tendons and the deep subcutis; a few cases involve the skin and bone tissue, whereas rare sites include the vulva and the breast [ 5 , 6 ]. After we retrospect 48 cases from 1981–2022 which took place in the head and neck region [ 1 , 7 ], we found that males account for 60.4%( n = 29), while females make up 37.5%( n = 18), and 2.1%( n = 1 case) was unavailable, the male-to-female ratio of about 1.5:1 (Fig. 5 A).…”

“…The pathogenesis of EMC remains controversial. Surgical or accidental trauma may be key factors, along with the inhalation of chemical carcinogens such as hydrocarbons [ 1 , 7 ]. Our patient did not report any intraoral region trauma.…”

“…Extraskeletal myxoid chondrosarcoma(EMC) is a rare malignant tumor accounting for less than 3% of all soft-tissue sarcomas [ 1 ], and mainly affects the lower limbs of male patients in their fifth and sixth decades of life, clinical signs and symptoms are mostly nonspecific [ 1 , 2 ]. EMC does not present convincing evidence of cartilaginous differentiation and recently, a neuroectodermic origin has been proposed [ 3 ].…”

“…EMC does not present convincing evidence of cartilaginous differentiation and recently, a neuroectodermic origin has been proposed [ 3 ]. Microscopically, the tumor cells of EMC typically present eosinophilic granular, frequently vacuolated cytoplasm with round to oval nuclei, morphologically resembling lipoblasts, immersed in a myxoid stroma in a multilobular arrangement, which is separated by fibrous septae [ 1 ]. The immunophenotype of EMC include positivity for vimentin and variable staining for S-100 and neuroendocrine markers Fluorescent in situ Hybridization (FISH) reveals mostly EWSR1-NR4A3 or TAF15-NR4A3 fusion [ 4 ].…”