Журнал клинических случаев

The Limits Of Diagnosis

Abstract

Joshua Greenwald*

Extraskeletal Myxoid Chondrosarcoma (EMC) is a rare Soft Tissue Sarcoma (STS) highly correlated with the NR4A3 gene rearrangement. This gene rearrangement has not been found in other tumors. However, its function is not yet fully known in cancer biology. Multiple prospective cohort studies show the population frequency of EMC as approximately 0.0001%. Cases of primary skeletal EMC’s have been reported, but the NR4A3 gene rearrangement is less correlated with it as compared to the soft tissue variant. EMC's tend to arise in the soft tissue of the proximal lower extremities and limb girdle in the fifth to sixth decade of life with a male predominance. Cases of EMC arising in the peripheral extremities are rarer still. And pathologic fractures secondary to chondrosarcoma’s are also highly unusual. The following patient presents with a primary tumour showing bland histology, arising in an infrequent location and in an atypical age group, primary to an unlikely tissue and associated with a rare presentation. Its only defining characteristic is the NR4A3 gene rearrangement. When does a rare gene rearrangement retain its specificity and serve as sufficient evidence to be diagnostic?