Thomas Mentzel, MD

Grossly, cases of myxofibrosarcoma often show a multinodular growth with myxoid cut surfaces, as shown here.

Myxofibrosarcoma is characterized by a variable cellularity and is composed of atypical fibroblastic cells that are set in a prominent myxoid stroma with numerous elongated curvilinear vessels image.



  • Myxofibrosarcoma (MFS)


  • Myxoid malignant fibrous histiocytoma


  • Myxofibrosarcoma represents a spectrum of malignant fibroblastic neoplasms with variably myxoid stroma and characteristic elongated curvilinear vessels



  • Incidence

    • One of the most common sarcomas in elderly patients

  • Age

    • Affects mainly patients in 6th-8th decade

    • Exceptionally rare in patients < 20 years old

  • Gender

    • Slight male predominance


  • Majority arise in limbs, including limb girdles (lower > upper extremities)

  • More rarely on trunk, head and neck region

  • Very rarely on hands and feet

  • Extremely rare in retroperitoneum and in abdominal cavity

  • 2/3 of cases arise in dermal/subcutaneous tissues


  • Painless mass

  • Slow growing


  • Surgical approaches

    • Complete wide excision


  • Local, often repeated recurrences in up to 50-60% of cases unrelated to histologic grade

  • Low-grade malignant neoplasms usually do not metastasize

    • May show tumor progression in subsequent recurrences and may acquire metastatic potential

  • Intermediate- and high-grade malignant neoplasms may develop metastases in 30-35% of cases

  • Overall 5-year survival is 60-70%

  • Depth of lesions and grade of malignancy do not influence recurrence rate

  • Percentage of metastases and tumor-associated mortality are higher in deep-seated neoplasms & high-grade malignant neoplasms

  • Local recurrences within < 12 months increase tumor associated mortality

  • Proliferative activity, percentage of aneuploid cells, and tumor vascularity are associated with histologic tumor grade


General Features

  • Superficially located neoplasms consist of multiple, variably gelatinous or firmer nodules

  • Deep-seated neoplasms often present as single mass with myxoid cut surfaces

  • Areas of tumor necrosis may be seen in high-grade neoplasms


Histologic Features

  • Broad spectrum of cellularity, cytologic atypia, and proliferative activity reflected by 3 grades of malignancy

    • Low-grade malignant myxofibrosarcoma

      • Hypocellular neoplasms

      • Few noncohesive tumor cells

      • Ill-defined eosinophilic cytoplasm

      • Enlarged hyperchromatic nuclei

    • Intermediate-grade malignant myxofibrosarcoma

      • More cellular and pleomorphic than low-grade neoplasms

      • No solid areas

      • No tumor necrosis

    • High-grade malignant myxofibrosarcoma

      • Large parts are composed of solid sheets and cellular fascicles

      • Spindled and pleomorphic tumor cells

      • Bizarre, multinucleated tumor giant cells

      • Numerous, often atypical mitoses

      • Areas of tumor necrosis may be present

      • At least focally, areas of lower grade neoplasm with prominent myxoid stroma and numerous curvilinear vessels

  • Multinodular growth with incomplete fibrous septa

  • Myxoid stroma

  • Prominent elongated, curvilinear, thin-walled blood vessels

  • Foci of inflammatory cells may be present

Cytologic Features

  • Spindled and stellate atypical fibroblastic cells

  • Often pseudolipoblasts are present

    • Pseudolipoblasts are vacuolated neoplastic fibroblastic cells

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Jul 9, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Myxofibrosarcoma
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