Low-Grade Fibromyxoid Sarcoma

 

Epidemiology:

    • F>M

 

Common sites:

    •  

 

Gross features:

    •  

 

Histologic features:

    • deceptively bland; similar appearance to fibromatosis and nerve sheath tumour
    • slight whirling, partially storiform appearance
    • may be extremely hypocellular
    • small, thin, spindly cells
      • bent and wavy nuclei occasionally
    • mitotic activity can be extremely low
    • giant hyalinizing rosettes with collagenized may be present
    • rare S100 positive cells may be present in rosettes

 

Immunophenotype:

Marker:

Sensitivity:

Specificity:

 S100 (neg)

 

 

 

Molecular features:

    • t(7;16)(q33;p11)
      • FUS-CREB3L2 fusion

 

Other features:

    • May metastasize (<10%), often years after removal of primary

 

References:

    • Sternberg 2004