Myxofibrosarcoma

Dr Henry Knipe and Dr Yuranga Weerakkody et al.

Myxofibrosarcoma is a malignant soft tissue tumor. It is classified as a type of a fibroblastic/myofibroblastic tumor.

Previously known as a myxoid variant of malignant fibrous histiocytoma 7.

Typically presents in older patients (6th decade) 3. There may be male predilection. Although rare in general, it is considered the most common soft tissue tumor to present in late adult life.

Patients often present with a painless enlarging soft tissue mass in the extremities.

Tends to favor the dermal and subcutaneous tissues than deeper soft tissues 1,5,7:

  • lower limbs (~77%)
  • trunk (~12%)
  • retroperitoneum/mediastinum (~8%)
  • head and neck (3-10%)

In contrast to most other histologic types of low-grade soft-tissue sarcoma, recurrent low-grade myxofibrosarcomas are often infiltrative; shows tapering, have tail-like margins with superficial spreading configuration and can even metastasize to various distant sites 3.

Myxofibrosarcoma often shows abnormal signal infiltration along the fascial plane on MRI 2.

  • T1: the myxoid component is often of low signal
  • T2/STIR: the myxoid component is high signal
  • T1 C+ (Gd): the myxoid component tends not to enhance while the remaining soft tissue component enhances

Prognosis will somewhat depend on grade 7

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Article information

rID: 10772
Synonyms or Alternate Spellings:
  • Myxoid variant of malignant fibrous histiocytoma
  • Myxoid variant of pleomorphic undifferentiated sarcoma

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Cases and figures

  • Case 1
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  • Case 2: rare occurence in calvarium
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  • Case 3: superficial
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