Soft tissue
Pericytic (perivascular)
Myofibroma / myofibromatosis

Topic Completed: 1 April 2013

Minor changes: 2 June 2020

Copyright: 2002-2019,, Inc.

PubMed Search: Myofibroma [title] soft tissue

Deepti Reddi, M.D.
Jerad M. Gardner, M.D.
Page views in 2019: 10,529
Page views in 2020 to date: 5,360
Cite this page: Reddi D, Gardner JM. Myofibroma / myofibromatosis. website. Accessed July 5th, 2020.
Definition / general
  • Benign solitary (myofibroma) or multicentric (myofibromatosis) neoplasms composed of myoid cells with thin-walled blood vessels
  • Myofibroma(tosis) is in a morphologic continuum with myopericytoma and infantile hemangiopericytoma (Clin Orthop Relat Res 2010;468:917)
  • Most common fibrous tumor of infancy
  • 60% congenital, most present before 2 years of age
  • More common in males
  • Usually solitary
  • 50% of solitary myofibromas occur in cutaneous/subcutaneous tissues of head and neck region
  • Myofibromatosis involves soft tissue and bone, more frequently occurs in deep soft tissues and may involve deep viscera
  • Unclear, rare familial cases have autosomal dominant inheritance
Clinical features
  • Cutaneous lesions present as purple macules and resemble a vascular neoplasm
  • Subcutaneous lesions present as painless freely mobile masses
  • Deep seated lesions may be fixed
Radiology description
  • Soft tissue lesions are either well circumscribed or infiltrative, often with calcification
  • Bony lesions occur as metaphyseal radiolucent lesions with a sclerotic margin in mature lesions
Prognostic factors
  • Myofibromas can regress spontaneously
  • Less than 10% of myofibromas recur, and are cured by local re-excision
  • Extent and location of visceral lesions determine complications
  • In rare cases, extensive organ involvement causes death
  • Pulmonary involvement is a negative prognostic factor
Case reports
Gross description
  • Median size of 2.5 cm, firm, fibrous, gray-white-brown cut surface, often central necrosis / cystic spaces with cheesy material or hemorrhage, better defined in dermis than deep soft tissue or viscera
Microscopic (histologic) description
  • Nodular or multinodular proliferation with zonal appearance
  • Peripheral zones have myoid short fascicles / whorls / nodules of plump myofibroblasts with pale pink cytoplasm and long, tapering nuclei with vesicular chromatin and 1 - 2 small nucleoli, but no atypia or pleomorphism, often associated with hyalinization, whorls / nodules can have a vaguely chondroid or chondromyxoid appearance
  • Central zones between the peripheral myoid nodules display cellular areas of round, polygonal or spindle cells with scant cytoplasm, hyperchromatic nuclei, arranged around thin walled branching ectatic "hemangiopericytic" vessels; often calcification, necrosis, hyalinization; often apparent subendothelial intravascular growth but still benign with minimal mitotic activity
Microscopic (histologic) images

Images hosted on PathOut servers:

Contributed by Hillary Rose Elwood, M.D.

Low power view showing well
circumscribed nodule with
variably cellular and hyalinized
pseudochondroid areas


Higher power views of biphasic proliferation includes immature cells in a hemangiopericytoma pattern and bundles of myofibroblastic cells

Contributed by Mark R. Wick, M.D.

Infantile type

Solitary, adult type


Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Fig 1: Solitary cutaneous lesion features zones of fibrous tissue with bundles of myofibroblasts and prominent thin-walled vessels
Fig 2: High power shows interface with normal collagen
Fig 3: Biphasic with immature cells in hemangiopericytoma pattern and bundles of myofibroblastic cells
Fig 4: Central hemangiopericytic area is rimmed by hyalinized myofibroblastic area
Fig 5: Junction between myofibroblastic cells and immature spindled cells
Fig 6: Myofibroblastic spindle cells and immature cells are arranged in hemangiopericytic pattern

Images hosted on other servers:

Infant lesion, arm tumor

Poorly circumscribed nodular tumor

Well circumscribed tumor

Cellular and keloid-like areas

Intracranial tumor

Myofibroblasts around capillaries and sclerosing areas

Tumor infiltrates skeletal muscle


Fascicles of myofibroblastic cells

Smooth muscle actin+

Tumor is CD34-, desmin-; vessels are CD34+ desmin+

Resembling hemangiopericytoma

Positive stains
Negative stains
Electron microscopy description
  • Continuum from fibroblasts to myofibroblasts to smooth muscle, with prominent dilated rough endoplasmic reticulum, longitudinal filament bundles with dense bodies and focal basal lamina
Differential diagnosis
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