Low-Grade Fibromyxoid Sarcoma

Low-Grade Fibromyxoid Sarcoma

Khin Thway, BSc, MBBS, FRCPath

Hematoxylin & eosin shows low-grade fibromyxoid sarcoma, as well as the interface between the myxoid areas image and the collagenous areas image of the tumor.

Hematoxylin & eosin shows low-grade fibromyxoid sarcoma with a giant rosette, composed of sparsely cellular collagenous tissue cuffed by a cellular distribution of tumor cells image.



  • Low-grade fibromyxoid sarcoma (LGFMS)


  • Fibrosarcoma, fibromyxoid type; hyalinizing spindle cell tumor with giant rosettes


  • Malignant fibroblastic neoplasm composed of bland spindle cells in collagenous and myxoid matrix, often with prominent collagenous nodules

  • Characterized by specific translocations producing fusion oncogenes

  • Despite histologically low-grade morphology, up to 30% can metastasize


Characteristic Translocations

  • Produce chimeric fusion genes

  • Cellular origin still unknown but mesenchymal neoplasm with cells of fibroblastic type



  • Incidence

    • True incidence unknown

    • Tumor probably underreported in literature due to its morphologic resemblance to other benign and malignant tumors

  • Age

    • Adults (typically in 4th decade), but wide age distribution

      • Significant proportion occur in patients < 18 years old

  • Gender

    • M > F


  • Mainly deep-seated but can also occur in dermis and subcutis

  • Proximal extremities (especially lower limbs) and trunk

  • Rarely other locations, including viscera

  • Superficial lesions have higher incidence in childhood


  • Painless mass

    • Many are of long duration


  • Surgical approaches

    • Wide excision

    • Long-term follow-up is mandatory, in view of potential for late metastases


  • Recurrence rates of up to 21%

    • Recurrence is lower in superficial cases

  • Metastatic rate of approximately 30% in genetically confirmed cases

    • > 80% of metastases appeared after 9 years

    • No reported metastases in superficial tumors


General Features

Jul 9, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Low-Grade Fibromyxoid Sarcoma

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