Extraskeletal myxoid chondrosarcoma: A case series and review of the literature

Abstract

Background Extraskeletal myxoid chondrosarcoma (EMC) is a rare malignant soft tissue sarcoma (STS) that accounts for less than 3% of all soft tissue tumors. The conventional treatment for primary EMC is wide local excision with or without radiation therapy. Materials and Methods This study was a retrospective review of all EMC cases treated within a single institution between 1992 and 2019. EMC was diagnosed using a combination of histologic morphology and immunostaining, with confirmatory fluorescent in situ hybridization. Overall survival (OS) and disease-specific survival (DSS) were defined using Kaplan–Meier analysis. Results Fifteen patients were evaluated, including 11 males and four females. The average age at presentation was 51.7 ± 20.4 years and the mean follow-up time was 61.5 months (range, 5–286 months). The average resected tumor size at largest dimension was 7.14 cm (range, 2.4–18.7). Twelve of fifteen (80%) patients underwent wide local excision, and nine of the twelve (75%) underwent local radiation therapy. The 1-, 5-, and 10-year OS was 80% (95% CI, 59.8–100), 72% (95% CI, 48.5–95.5), and 72% (95% CI, 48.5–95.5), respectively. The 1-, 5-, and 10-year DSS was 92.3% (95% CI, 77.8–100), 83.1% (95% CI, 61.5–100), and 83.1% (95% CI, 61.5–100), respectively. At last follow-up, 11 patients were alive and ten (90.9%) were disease free. Conclusions Extraskeletal myxoid chondrosarcoma is a very rare STS most often seen in males and in the extremities. Our cohort was too small to provide meaningful statistical analysis; however, we observed lower rates of local recurrence in patients treated with radiation.

Juxta-articular extraskeletal myxoid chondrosarcoma mistaken for a benign cyst presenting with multiple lung metastases

“…EMC, first described by Enzinger and Shiraki as a discrete entity in 1972 [1] , is a rare malignant mesenchymal neoplasm of uncertain differentiation accounting for less than 3% of soft tissue sarcomas [2] . It has a male predilection and usually presents in the deep soft tissues of the proximal extremities and limb girdles (approximately 70%) with a subcutaneous location accounting for the remainder of cases (27%-33%) [ 3 , 4 ].…”

“…EMC more commonly involves the lower limbs. The upper extremities and the trunk are less affected [2] . In their study of 86 patients, Drilon et al.…”

Metastatic extraskeletal myxoid chondrosarcoma presenting as a forehead mass

“… 4 The most common site of distant metastasis is the lungs; however, other sites include lymph nodes, bony skeleton, soft tissue, and the brain. 8 , 9 …”

“…4 The most common site of distant metastasis is the lungs; however, other sites include lymph nodes, bony skeleton, soft tissue, and the brain. 8,9 Our patient underwent surveillance with yearly chest computed tomography and nuclear bone scans after the initial diagnosis of EMC of the foot and was considered disease-free for 9 years before presenting to the dermatology clinic for a forehead mass presumed to be a lipoma. Other differential considerations for a mass on the forehead included dermoid cyst, meningocele/meningocephalocele, osteoma, fibrous dysplasia, osteoid osteoma, ossifying fibroma, giant cell tumor, aneurysmal bone cyst, neuroblastoma, lymphoma, Ewing sarcoma, osteogenic sarcoma, calcified cephalohematoma, and growing skull fracture (leptomeningeal cyst).…”