Low Grade Fibromyxoid Sarcoma
Definition
- Cytologically bland malignant neoplasm with alternating fibrous and myxoid stroma of low grade / low malignant potential
Alternate / Historical Names
- Evans tumor
- Hyalinizing spindle cell tumor with giant rosettes
- Low grade fibrosarcoma with palisaded granuloma like bodies
Diagnostic Criteria
- Grossly circumscribed, microscopically infiltrating
- Alternating fibrous and myxoid stroma
- Swirling, whorled pattern
- Giant collagen rosettes in some cases
- May simulate palisaded granulomas
- Originally reported as hyalinizing spindle cell tumor with giant rosettes
- Metastasis not observed in original report but subsequently has been reported
- Appears to be in the spectrum of low grade fibromyxoid sarcoma
- Smaller rosettes may be seen in typical low grade fibromyxoid sarcoma
- Rosettes have been seen in metastases of a typical low grade fibromyxoid sarcoma
- Clinicopathologic features otherwise appear identical
- Generally hypocellular with bland spindle or stellate cells
- Dark oval nuclei
- Intranuclear inclusions may be seen
- Pleomorphism absent or slight
- Low to moderate cellularity
- Scant cytoplasm
- Mitotic figures rare
- One reported case with abundant hemosiderin and synovial like clefts
- MUC4 positive (see Supplemental Studies)
- Focally occasional cases may deviate from above in primaries, recurrences or metastases
- Focal hypercellular areas with epithelioid cells
- May have herringbone pattern
- Focally moderately hyperchromatic or pleomorphic
- Focal necrosis
- Increased capillary vascularity with curvilinear vessels
- Focally mitotic figures >1/10 hpf
- No clinical significance in two year followup
- Based on a shared translocation and cases with mixed features sclerosing epithelioid fibrosarcoma has been proposed to form a spectrum with low grade fibromyxosarcoma
Richard L Kempson MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/last update: 10/15/07, 1/22/14
