Stanford School of Medicine
Surgical Pathology Criteria
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Myofibroma, Solitary and Multicentric


  • Generally biphasic tumor composed of mature and immature myofibroblastic cells with hemangiopericytoma-like vessels. May be solitary or multicentric

Alternate / Historical Names

  • Congenital fibrosarcoma
  • Congential generalized fibromatosis
  • Infantile hemangiopericytoma
  • Infantile myofibromatosis
  • Myofibromatosis

Diagnostic Criteria

  • Superficial lesions circumscribed, deep lesions infiltrative
    • Both may be microscopically infiltrative
  • Generally biphasic nodules (see below for exceptions)
    • Light staining bundles of mature nyoid cells usually on periphery of nodules
      • Moderate amount of well defined cytoplasm
      • Generally vesicular nuclei
      • Peripheral chronic inflammation may be present
    • Dark staining areas of primitive oval to spindle cells usually in center of nodules
      • Scant indistinct cytoplasm
      • Small dark nuclei
      • Hemangiopericytoma-like vascular pattern
  • Mitotic figures may be frequent
    • No atypical figures
  • Atypical features are of no clinicall significance
    • Intravascular growth frequent
    • Primtive spindle cell areas may be very cellular and predominate
      • May approach cellularity of fibrosarcoma but lacks atypia
    • Mild pleomorphism may be present
    • Central necrosis may be present
      • Rare in infants
  • Both cell types actin positive
  • Exceptions to usual pattern
    • Occasional domination of either type
    • Mature cell type more predominant in lung
    • Immature cell type more predominant in bone
    • Reversal of zonation occasionally seen in adults
  • Infantile lesions show common features with infantile hemangiopericytoma
    • We consider them to be the same entity
  • Adult lesions have been proposed as part of a spectrum including glomangiopericytoma and myopericytoma
  • Richard L Kempson MD
    Robert V Rouse MD
    Department of Pathology
    Stanford University School of Medicine
    Stanford CA 94305-5342

    Original posting / last update: 8/10/08, 11/23/14


Supplemental studies


Smooth muscle actin and muscle specific actin positive, may be weak, both cell types
Vimentin positive
Desmin negative to focal/faint
S100 negative
CD34 0-25%


Differential diagnosis


Infantile hemangiopericytoma
We consider this to be the same tumor as myofibroma


Glomangiopericytoma and myopericytoma It has been proposed that these two tumors and myofibroma are part of the same spectrum
Myofibroma Glomangiopericytoma and Myopericytoma
Small primitive cells present Lacks small primitive component
Lacks perivascular pattern Perivascular distribution
Some overlap may occur


Myofibroma Inflammatory Myofibroblastic Tumor
90% <2 years Usually age 0-14 years
Biphasic nodules with immature cells No immature cells
Hemangiopericytomatous vessels No HPC like vessels
Rare in abdomen Frequent in abdomen


Myofibroma Infantile Fibrosarcoma
Random spindle cell pattern Fascicular pattern
Biphasic mature and immature areas No biphasic pattern
Atypical mitotic figures rare Atypical mitotic figures common


Solitary Fibrous Tumor Myofibroma
Lacks biphasic nodular pattern Biphasic nodular pattern
CD34 >95% positive CD34 negative
Actin focal, rare Actin positive
Multiple lesions uncommon 25% of cases multifocal
Rare in infants Rare over age 2 years
Both frequently show a hemangiopericytoma-like vascular pattern


Hemangiopericytoma Myofibroma
Rare under age 20 years Rare over age 2 years
Lacks biphasic nodular pattern Biphasic nodular pattern
CD34 50% positive CD34 negative
Actin focal, rare Actin positive
Multiple lesions uncommon 25% of cases multifocal
Both frequently show a hemangiopericytoma-like vascular pattern


Leiomyoma Myofibroma
Lacks biphasic pattern Biphasic nodular pattern
Lacks HPC-like vascular pattern Frequent HPC-like vascular pattern
Multiple lesions uncommon 25% of cases multifocal
Desmin variable Desmin negative


Nodular Fasciitis Myofibroma
Lacks biphasic pattern Biphasic nodular pattern
Lacks HPC-like vascular pattern Frequent HPC-like vascular pattern
Multiple lesions rare 25% of cases multifocal
Desmin variable Desmin negative


Fibrous Hamartoma of Infancy Myofibroma
Triphasic lesion with spindle cell fibrous areas, adipose tissue and clusters of immature mesenchymal cells Biphasic lesion with outer spindled cells and inner immature cells
Lacks hemangiopericytomatous vessels Hemangiopericytoma-like vessels frequent


Myofibroma Inclusion Body Fibromatosis
Rare on digits Usually on digits
Biphasic nodules with central primitive cells Lacks primitive cells and perivascular clustering of cells
No inclusions Inclusions


Myofibroma Plexifiorm Fibrohistiocytic Tumor
Circumscribed Plexiform rays infiltrate fat
Central primitive dark cells with hemangiopericytoma-like vessels Nodules with histiocyte-like cells and multinucleated cells

Lesions that may demonstrate a prominent hemangiopericytoma-like vascular pattern


  • Location
    • Skin, subcutaneous tissue, muscle
      • Bones, organs less common
    • Head, neck most common
    • Rarely seen in almost any other site
  • 75% solitary lesions
    • Solitary lesions usually superficial
  • Multiple lesions may be few to >100
    • Cases with multiple lesions may be superficial or deep and include more organ involvement
  • Age
    • 90% <2 years
    • 60% near birth
    • Rare in adults
      • Usually single
      • Usually superficial
      • Infrequent recurrence
      • Usually on head, neck, upper trunk
  • May show autosomal dominant inheritance
    • Rarely associated with congenital defects
  • Clinical appearance
    • 0.5 to >7 cm
    • May be white or purple nodule
    • May appear to be a scar
  • May show growth after birth with later stabilization or regression
  • Individual lesions cured by excision
    • May not be possible in multifocal cases with visceral involvement
  • Visceral involvement may cause death


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  • 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, 5th edition, 2008
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  • Granter SR, Badizadegan K, Fletcher CD.  Myofibromatosis in adults, glomangiopericytoma, and myopericytoma: a spectrum of tumors showing perivascular myoid differentiation.  Am J Surg Pathol 1998 May;22(5):513-25.
  • Jennings TA, Duray PH, Collins FS, Sabetta J, Enzinger FM.  Infantile myofibromatosis. Evidence for an autosomal-dominant disorder.  Am J Surg Pathol 1984 Jul;8(7):529-38.
  • Bracko M, Cindro L, Golouh R.  Familial occurrence of infantile myofibromatosis.  Cancer 1992 Mar 1;69(5):1294-9.
  • Briselli MF, Soule EH, Gilchrist GS.  Congenital fibromatosis: report of 18 cases of solitary and 4 cases of multiple tumors.  Mayo Clin Proc 1980 Sep;55(9):554-62
  • Chung EB, Enzinger FM.  Infantile myofibromatosis.  Cancer 1981 Oct 15;48(8):1807-18.
  • Mentzel T, Calonje E, Nascimento AG, Fletcher CD.  Infantile hemangiopericytoma versus infantile myofibromatosis. Study of a series suggesting a continuous spectrum of infantile myofibroblastic lesions.  Am J Surg Pathol 1994 Sep;18(9):922-30.
  • Speight PM, Dayan D, Fletcher CD.  Adult and infantile myofibromatosis: a report of three cases affecting the oral cavity.  J Oral Pathol Med 1991 Sep;20(8):380-4.
  • Hogan SF, Salassa JR.  Recurrent adult myofibromatosis. A case report.  Am J Clin Pathol 1992 Jun;97(6):810-4.Spraker MK, Stack C, Esterly NB.  Congenital generalized fibromatosis: a review of the literature and report of a case associated with porencephaly, hemiatrophy, and cutis marmorata telangiectatica congenita.  J Am Acad Dermatol 1984 Feb;10(2 Pt 2):365-71.
  • Linos K, Carter JM, Gardner JM, Folpe AL, Weiss SW, Edgar MA. Myofibromas with atypical features: expanding the morphologic spectrum of a benign entity. Am J Surg Pathol. 2014 Dec;38(12):1649-54. PubMed PMID: 24921644.
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