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Myxofibrosarcoma

Synonyms: Myxoid Malignant Fibrous Histiocytoma

Definition

Malignant stromal tumors of fibroblastic origin with a spectrum of morphology that includes variable pleomorphism, myxoid appearance and typical vascular pattern.

Clinical Features

  • Usually:
    • extremity
    • adult

Gross Pathology

  • Usually:
    • attached to fascia, or
    • within a major muscle3
  • Mucoid:
    • resemble myxoid liposarcomas (Fig. 1
      Gross appearance of myxofibrosarcoma.

      Fig. 1: Gross appearance of myxofibrosarcoma.

      )

Histopathology

  • If low-grade:
    • resemble liposarcoma
    • abundant matrix of acid mucopolysaccharides
    • high vascularity
    • cells resembling lipoblasts4,5 (Figs 2–4
      Myxofibrosarcoma. Alternation of cellular and myxoid areas.

      Fig. 2: Myxofibrosarcoma. Alternation of cellular and myxoid areas.

      Myxofibrosarcoma. Moderate pleomorphism of tumor cells.

      Fig. 3: Myxofibrosarcoma. Moderate pleomorphism of tumor cells.

      Myxofibrosarcoma. Lipoblast-like tumor cells floating in myxoid material.

      Fig. 4: Myxofibrosarcoma. Lipoblast-like tumor cells floating in myxoid material.

      )

Diagnosis

  • Identified by:
    • presence elsewhere in tumor of typical areas of malignant fibrous histiocytoma
    • absence of true lipoblasts:
      • should contain neutral fat in cytoplasmic vacuoles rather than acid mucopolysaccharides

Differential Diagnosis

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Prognosis

  • Prognostic factors:
    • poor prognosis:
      • may be altered expression of cell cycle regulators (such as reduced expression of p21)9
    • microscopic grade:
      • but even lower grade tumors have a potential for recurrence10

References

3 Mansoor A, White CR. Myxofibrosarcoma presenting in the skin: clinicopathological features and differential diagnosis with cutaneous myxoid neoplasms. Am J Dermatopathol. 2003;25:281–286.

4 Graadt van Roggen JF, Hogendoorn PC, Fletcher CD. Myxoid tumours of soft tissue. Histopathology. 1999;35:291–312.

5 Mentzel T, Calonje E, Wadden C, Camplejohn RS, Beham A, Smith MA, et al. Myxofibrosarcoma: a clinicopathologic analysis of 75 cases with emphasis on the low-grade variant. Am J Surg Pathol. 1996;20:391–405.

6 Lagacé R, Delage C, Seemayer TA. Myxoid variant of malignant fibrous histiocytoma. Ultrastructural observations. Cancer. 1979;43:526–534.

7 Tsuneyoshi M, Hashimoto H, Enjoji M. Myxoid malignant fibrous histiocytoma versus myxoid liposarcoma. A comparative ultrastructural study. Virchows Arch [A]. 1983;400:187–199.

8 Weiss SW, Enzinger FM. Myxoid variant of malignant fibrous histiocytoma. Cancer. 1977;39:1672–1685.

9 Oda Y, Takahira T, Kawaguchi K, Yamamoto H, Tamiya S, Matsuda S, et al. Altered expression of cell cycle regulators in myxofibrosarcoma, with special emphasis on their prognostic implications. Hum Pathol. 2003;34:1035–1042.

10 Huang H-Y, Lal P, Qin J, Antonescu Cr. A comparison of 3 grading schemes to predict outcome of low grade myxofibrosarcoma (Abstract). Mod Pathol. 2003;16:14A.

Uncited references

1 Angervall L, Kindblom L-G, Merck C. Myxofibrosarcoma. A study of 30 cases. Acta Pathol Microbiol Scand (A). 1977;85:127–140.

2 Kindblom L-G, Merck C, Angervall L. The ultrastructure of myxofibrosarcoma. A study of 11 cases. Virchows Arch [A]. 1979;381:121–139.

Last updated: 21 Feb 2006

Myxofibrosarcoma

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