The extracompartmental tumoral invasion of extraskeletal myxoid chondrosarcoma induces distant metastasis

Abstract

Background: Extraskeletal myxoid chondrosarcoma (EMC) is a rare malignant soft-tissue tumor and often shows extracompartmental tumoral invasion. The aim of our study was to investigate the clinical features, especially extra - compartmental tumoral invasion (ETI) of EMC. Patients and Methods: A total of 35 operative patients diagnosed with EMC were enrolled in this study from January 1980 to March 2018 in the Cancer Institute Hospital of The Japanese Foundation for Cancer Research. The operative procedure was principally wide excision. Univariate analysis assessed how clinicopathological factors (e.g. age, gender, tumor site, tumor size, histo - pathological grade, surgical margin, metastasis before operation, barrier invasion, local recurrence, metastasis after operation) influenced patient prognosis. We assessed how clinicopathological factors influenced ETI of EMC. Results: Among 35 patients, 10 patients showed ETI. The average followup was 5.57 (range=0.2-20 years). The 5- and 10-year overall survival was 91.3% and 71.2%, respectively. The 5- and 10-year overall survival of patients with M0 disease was 96.1% and 73.2%, respectively, while both were 75.0% for those with M1 disease, respectively. The patients with distant metastasis at first visit tended to have a poor prognosis (p=0.07). It is notable that all of the 10 patients with ETI had distant metastasis after surgery. Conclusion: Patients with distant metastasis at first visit tended to have a poor prognosis. ETI of EMC induced distant metastasis after surgery. Patients with ETI of EMC should, therefore, be carefully monitored over a prolonged period. Extraskeletal myxoid chondrosarcoma (EMC) is a rare softtissue malignancy characterized by uniform spindle cells arranged in a reticular growth pattern in abundant myxoid stroma (1, 2). The disease generally arises in the deep soft tissues of the proximal extremities and limbs and comprises multiple gelatinous nodules divided by fibrous septa but occurrence in several unusual regions such as the scrotum and finger have been reported (3-5). Considered to be slowgrowing, EMC is associated with relatively long survival but has a risk of local recurrence or distant metastasis (1,2, 6, 7). Histologically, the tumor is classified as a tumor of uncertain differentiation due to its lack of cartilaginous differentiation, although originally believed to be a variant of chondrosarcoma (3). The tumor is distinguished from other sarcomas by its unique histology and characteristic chromosomal translocation, typically t(9;22)(q22;q12.2), fusing Ewing sarcoma breakpoint region 1 (EWSR1) to nuclear receptor subfamily 4 group A member 3 (NR4A3) (genes formerly known as Ewing sarcoma (EWS) and chimerin (CHN), translocated in extraskeletal chondrosarcoma (TEC) or neuron-derived orphan receptor 1 (NOR1), respectively) (8-10). The fusion gene products are responsible for alterations in cellular growth and differentiation (11). To our knowledge, published reports documenting the clinical features of EMC are limited (12). EMC often exhibits extracompartmental tumoral invasion (ETI) (13). The aim of our study was to investigate the clinical features and ETI of EMC.