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low-grade fibromyxoid sarcoma

Monday 15 December 2003

fibromyxoid sarcoma, LGFMS; Hyalinizing spindle cell tumor with giant rosettes; Evans tumor


Definition: Low-grade fibromyxoid sarcoma is a rare, benign-appearing soft tissue fibromyxoid tumor with an aggressive clinical course characterized by multiple local recurrences over several years, with ultimate spread to lung and occasionally to bone.

These are rare sarcomas which are commonly seen in young to middle-aged adults and typically occur in a subfascial location in the proximal extremities or trunk as painless, deep-seated, slowly-enlarging soft tissue masses.

Low-grade fibromyxoid sarcomas (LGFMS) bear either the t(7,16) (q32-34;p11) or t(11,16) (p11;p11) translocations, resulting in FUS-CREB3L2 or FUS-CREB3L1 fusions, respectively.


- Low-grade fibromyxoid sarcomas (LGFMS)


Grossly, the tumor is an oval multilobulated mass, ranging in size from 2 to 20 cm in diameter. Although most of the lesions appear well circumscribed, they can extensively infiltrate the surrounding soft tissue. The cut surface has a whorled white-tan appearance. Cystic degeneration, which was prominent in our first case, is an uncommon finding.


- admixture of heavily collagenized and myxoid areas,
- fibroid and myxoid areas
- deceptively bland spindle cells arranged in a whorling pattern,
- collagen rosette
- arcades of curvilinear blood vessels, prominent vascularization



The immunohistochemical profile has suggested a neural phenotype, with the cells forming the rosettes being Leu-7, S-100, and pgp 9.5 positive and the spindle cells usually being negative.

Hyalinizing spindle cell tumor with giant rosettes - HSCTGR

In approximately 40% of cases of LGFMS the stroma is punctuated by the presence of a variable number of large rosette-like structures that merge imperceptibly with the surrounding hyalinized or spindled stroma.

The term HSCTGR has been used for those LGFMS where the collagen rosettes are particularly prominent and well-formed.


- hyalinizing spindle cell tumor with giant rosettes (HSCT)
- deep low-grade fibromyxoid sarcoma
- superficial low-grade fibromyxoid sarcoma

  • sub-cutaneous low-grade fibromyxoid sarcoma
  • dermal low-grade fibromyxoid sarcoma

Differential diagnosis

- fusiform cell tumors (spindle cell tumors)

  • desmoid fibromatosis (deep fibromatosis)
  • leiomyosarcoma
  • myofibrosarcoma
  • sclerosing epithelioid fibrosarcoma
  • low-grade fibrosarcoma
  • classic fibrosarcoma
  • inflammatory myxohyaline/myxoinflammatory fibroblastic sarcoma
  • nodular fasciitis

- myxoid tumors and fibromyxoid tumors

Low-grade myxofibrosarcoma has more cellular atypia and less swirling of tumor cells in a uniformly myxoid stroma. Myxoid neurofibroma shows more wavy nuclei of the spindle cells and strong S-100 positivity.

- tumors with osteoid or tumors with pseudo-osteoid

  • The osteoid, in rare cases of osteosarcoma, may be confused for the collagen rosettes.

Calcification in the material and the surrounding marked nuclear pleomorphism will help in settling the issue.


Low-grade fibromyxoid sarcomas (LGFMS) bear either the t(7,16) (q32-34;p11) or t(11,16) (p11;p11) translocations, resulting in FUS-CREB3L2 or FUS-CREB3L1 fusions, respectively.

- t(7;16)(q33;p11) translocation creating FUS-CREB3L2 fusion gene (12960807) (also found in hyalinizing spindle cell tumor with giant rosettes).

- t(11,16)(p11;p11) translocation creating FUS-CREB3L1 fusion gene.

Molecular biology

- FUS-CREB3L2 fusion gene (or FUS-BBF2H7) by t(7;16)(q33;p11) (7q33 amd 11p11) (15139001)
- FUS-CREB3L1 fusion gene
- EWSR1-CREB3L2 fusion gene

- Fusion transcripts were mainly detected in frozen tissues, using reverse transcription-polymerase chain reaction. FUS-CREB3L1 / CREB3L2 fusion transcripts can also be detected in paraffin-embedded LGFMS in a sensitive manner, using reverse transcription-polymerase chain reaction. Most fusion-positive LGFMS are EMA-positive and CD34/S100/smooth muscle actin negative.

- The presence of epithelioid cells and fusion transcripts in both LGFMS and a subset of sclerosing epithelioid fibrosarcoma suggest that these neoplasms might be related.

Prognosis and management

Though the lesion appears bland in morphology, long-term follow-up has revealed that it has a potential for metastasis, especially to the lungs.

Improved recognition and treatment have improved the prognosis of the lesion but, nevertheless, prolonged follow-up is necessary.

Differential diagnosis

- myxofibrosarcoma

See also

- low-grade fibrosarcomas
- fibromyxoid tumors
- myxoid tumors


- Guillou L, Benhattar J, Gengler C, Gallagher G, Ranchere-Vince D, Collin F, Terrier P, Terrier-Lacombe MJ, Leroux A, Marques B, Aubain Somerhausen Nde S, Keslair F, Pedeutour F, Coindre JM. Translocation-positive low-grade fibromyxoid sarcoma: clinicopathologic and molecular analysis of a series expanding the morphologic spectrum and suggesting potential relationship to sclerosing epithelioid fibrosarcoma: a study from the French Sarcoma Group. Am J Surg Pathol. 2007 Sep;31(9):1387-402. PMID: 17721195

- Mertens F, Fletcher CD, Antonescu CR, Coindre JM, Colecchia M, Domanski HA, Downs-Kelly E, Fisher C, Goldblum JR, Guillou L, Reid R, Rosai J, Sciot R, Mandahl N, Panagopoulos I. Clinicopathologic and molecular genetic characterization of low-grade fibromyxoid sarcoma, and cloning of a novel FUS/CREB3L1 fusion gene. Lab Invest. 2005 Mar;85(3):408-15. PMID: 15640831

- Reid R, de Silva MV, Paterson L, Ryan E, Fisher C. Low-grade fibromyxoid sarcoma and hyalinizing spindle cell tumor with giant rosettes share a common t(7;16)(q34;p11) translocation. Am J Surg Pathol. 2003 Sep;27(9):1229-36. PMID: 12960807

- Shidham VB, Ayala GE, Lahaniatis JE, Garcia FU. Low-grade fibromyxoid sarcoma: clinicopathologic case report with review of the literature. Am J Clin Oncol. 1999 Apr;22(2):150-5. PMID: 10199449