Stanford School of Medicine

Surgical Pathology Criteria

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Ossifying Fibromyxoid Tumor


  • Tumor composed of lobules and cords of small bland cells in a myxohyaline background with frequent peripheral ossification

Diagnostic Criteria

  • Grossly circumscribed
    • May have microscopic micronodular extension
  • Peripheral layer of lamellar bone in most cases
    • May be focal
    • Occasionally within tumor
    • Rarely extensive
    • Occasional cases have only fibrous capsule
  • Lobules and cords of bland cells
    • Small, usually round to oval epithelioid cells, occasionally spindled
    • Bland vesicular nuclei
    • Cytoplasm pale to eosinophilic
    • Mitotic figures rare
    • Nucleoli small to absent
  • Stroma myxoid to hyaline
    • Prominent thin walled blood vessels
  • Predominantly subcutaneous, occasionally intramuscular
    • Occasionally involving skin
  • Features associated with recurrence or metastasis
    • High cellularity
    • High nuclear grade
    • Mitotic count >2/50 hpf
    • Infiltrative growth
    • The diagnosis of malignant ossifying fibromyxoid tumor should only be made in the presence of areas of typical tumor or with a prior history of typical tumor
  • Other unusual features
    • Mucinous microcysts
    • Vascular invasion
    • Necrosis
    • Lack of myxoid stroma
    • Microcalcifications
    • Associated epidermoid cysts
    • Chondroid differentiation with binucleate chondrocytes
    • Multinucleated giant cells

    Richard L Kempson MD
    Robert V Rouse MD
    Department of Pathology
    Stanford University School of Medicine
    Stanford CA 94305-5342

    Original posting/updates: 2/3/07, 8/17/08, 11/20/11

Supplemental studies


  Four Largest Series Including Other Reports
S100 60-94% 60-94%
Desmin 10-50% 10 to 50%
Smooth muscle actin 0-5% 2 to 50%
GFAP 7% 7-40%
CD57 not tested 60%
NSE not tested 60%
Keratin 5-13% 0-13%
EMA 0-2% 0-2%
Neurofilament 90% negative
MUC4 12% not tested
Data for benign tumors from four largest series: Enzinger 1989, Folpe 2003, Miettinen 2008, Graham 2011
Malignant tumors are reported more frequently positive for keratin, EMA and smooth muscle actin and less frequently positive for S100 and desmin (Graham 2011)

INI1 staining shows a mosaic pattern with loss of expression in 30-60% of cells in 74% of cases (Graham 2011)

Genetic study

  • No consistent clonal chromosomal abnormalities

Differential Diagnosis

Osteosarcoma Ossifying Fibromyxoid Tumor
Cytologic atypia Bland cytology
Tumor of bone Most are superficial and small
Atypical "tumor" bone Normal appearing lamellar bone


Glomus Tumor Ossifying Fibromyxoid Tumor
No ossification Frequent ossification
Actin positive, S100 negative Actin variable, most are S100 positive


Myxoid Chondrosarcoma Ossifying Fibromyxoid Tumor
No peripheral ossification Frequent peripheral ossification
Most are deep and large Most are superficial and small
PAS positive PAS negative


  • Age 6-83 years
    • Most over 40
    • Rare under 20
  • Most on extremities
    • Most others on trunk and head and neck
    • May be intraoral
    • Rare retroperitoneal cases reported
  • Predominantly subcutaneous, occasionally intramuscular
    • Occasionally involving skin
  • Median size 4 cm, rarely >10cm
  • Recurrence rate reported from 0 to 27%
    • Frequently occurs late (>10 years)
  • Metastatic rate reported as high as 16%
    • Incidence may depend upon strictness of application of diagnostic criteria
    • Metastases reported with and without recurrences

Grading / Staging / Report

Pathologic features predict aggressive behavior

  • Features associated with both recurrence and metastasis (proposed name: malignant ossifying fibromyxoid tumor)
    • High cellularity
    • High nuclear grade
    • Mitotic count >2/50 hpf
  • Features associated with only recurrence
    • Infiltrative growth
  • Features not associated with aggressive behavior
    • Size >4 cm
    • Atypical mitotic figures
    • Necrosis
    • Presence or distribution of bone
    • Vascular invasion
  • 2 of 8 cases with metastases in this series did not display the above features
  • Data from Folpe and Weiss 2003

Staging not applicable

The surgical pathology report should contain or address the following:

  • Location
  • Type of resection or biopsy
  • Histologic diagnosis
  • Managerial category IIc (Local recurrence common; metastasis can rarely occur without dedifferentiation)
  • Presence of atypical features
  • Stage
  • Size
  • Depth (dermis, subcutis, below fascia, body cavity)
  • Margins
    • Involved
    • Not involved
  • Results of supplementary studies if performed
  • Relationship to other specimens from the same patient


Soft tissue tumors containing osteoid or bone

Soft tissue lesions that frequently are prominently myxoid


  • Kempson RL, Fletcher CDM, Evans HL, Henrickson MR, Sibley RS. Tumors of the Soft Tissues, Atlas of Tumor Pathology, AFIP Third Series, Fascicle 30, 2001
  • Fletcher CDM, Unni KK, Mertens F. Pathology and Genetics of Tumours of Soft Tissue and Bone, World Health Organization Classification of Tumours 2002
  • Weiss SW, Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors, 4th edition, 2001
  • Folpe AL, Weiss SW. Ossifying fibromyxoid tumor of soft parts: a clinicopathologic study of 70 cases with emphasis on atypical and malignant variants. Am J Surg Pathol. 2003 Apr;27(4):421-31.
  • Sovani V, Velagaleti GV, Filipowicz E, Gatalica Z, Knisely AS. Ossifying fibromyxoid tumor of soft parts: report of a case with novel cytogenetic findings. Cancer Genet Cytogenet 2001 May;127(1):1-6
  • Motoyama T, Ogose A, Watanabe H. Ossifying fibromyxoid tumor of the retroperitoneum. Pathol Int 1996 Jan;46(1):79-83
  • Matsumoto K, Yamamoto T, Min W, Yamada N, Asano G, Moriyama M, Matsumoto T. Ossifying fibromyxoid tumor of soft parts: clinicopathologic, immunohistochemical and ultrastructural study of four cases. Pathol Int 1999 Aug;49(8):742-6
  • Ijiri R, Tanaka Y, Misugi K, Sekido K, Nishi T. Ossifying fibromyxoid tumor of soft parts in a child: a case report. J Pediatr Surg 1999 Aug;34(8):1294-6
  • Ekfors TO, Kulju T, Aaltonen M, Kallajoki M. Ossifying fibromyxoid tumour of soft parts: report of four cases including one mediastinal and one infantile. APMIS 1998 Dec;106(12):1124-30
  • Zamecnik M, Michal M, Simpson RH, Lamovec J, Hlavcak P, Kinkor Z, Mukensnabl P, Matejovsky Z, Betlach J. Ossifying fibromyxoid tumor of soft parts: a report of 17 cases with emphasis on unusual histological features. Ann Diagn Pathol 1997 Dec;1(2):73-81
  • Kilpatrick SE, Ward WG, Mozes M, Miettinen M, Fukunaga M, Fletcher CD. Atypical and malignant variants of ossifying fibromyxoid tumor. Clinicopathologic analysis of six cases. Am J Surg Pathol 1995 Sep;19(9):1039-46
  • Schofield JB, Krausz T, Stamp GW, Fletcher CD, Fisher C, Azzopardi JG. Ossifying fibromyxoid tumour of soft parts: immunohistochemical and ultrastructural analysis. Histopathology 1993 Feb;22(2):101-12
  • Williams SB, Ellis GL, Meis JM, Heffner DK. Ossifying fibromyxoid tumour (of soft parts) of the head and neck: a clinicopathological and immunohistochemical study of nine cases. J Laryngol Otol 1993 Jan;107(1):75-80
  • Enzinger FM, Weiss SW, Liang CY. Ossifying fibromyxoid tumor of soft parts. A clinicopathological analysis of 59 cases. Am J Surg Pathol 1989 Oct;13(10):817-27
  • Miettinen M, Finnell V, Fetsch JF. Ossifying fibromyxoid tumor of soft parts--a clinicopathologic and immunohistochemical study of 104 cases with long-term follow-up and a critical review of the literature. Am J Surg Pathol. 2008 Jul;32(7):996-1005.
  • Graham RP, Dry S, Li X, Binder S, Bahrami A, Raimondi SC, Dogan A, Chakraborty S, Souchek JJ, Folpe AL. Ossifying fibromyxoid tumor of soft parts: a clinicopathologic, proteomic, and genomic study. Am J Surg Pathol. 2011 Nov;35(11):1615-25
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