Epidemiology
A rare sarcoma of young or middle-aged adults, often located deep in the trunk or limbs. It can look non-aggressive under the microscope but recur or metastasize late; prolonged monitoring is important.
Basic features
It can look deceptively benign under the microscope, but it has the potential for late recurrence and metastasis; the diagnosis is supported by the characteristic FUS::CREB3L2 fusion and by MUC4 expression, which separate it from benign fibromyxoid lesions that look similar.
Usual treatment
Wide resection is essential; radiotherapy is decided based on margins, size, and location.
Outcomes and prognosis
In the medium term the prognosis is usually good, but follow-up must be long because it can recur or spread late; modern series, with more precise molecular diagnosis, describe metastasis in a minority of cases (less frequent than older publications suggested).