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Fibrosarcoma - Skin
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Fibrosarcoma - Skin

Contributors: Erik Domingues MD, Nikki Levin MD, Jeffrey D. Bernhard MD, Noah Craft MD, PhD, Lindy P. Fox MD, Lowell A. Goldsmith MD, MPH, Michael D. Tharp MD
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Fibrosarcoma, also known as mesenchymal cell tumor or fibroblastic malignancy, is a rare tumor of malignant fibroblasts that usually occurs in young to middle-aged adults but can occur in children as well. Fibrosarcomas may arise in soft tissues or bones. They generally present as a painless, enlarging, poorly defined mass in the soft tissues, found deep to the fascia, and most commonly occur in the thigh and posterior knee.

Fibrosarcoma of soft tissues can go undetected for a long period of time, compared to fibrosarcoma of the bone, because of its painless character. Fibrosarcoma of soft tissues may occur in areas of prior burn scars or irradiation. Mutations in p53 have been identified in fibrosarcomas.

Fibrosarcoma of the bone may present with pain, swelling, and pathologic fractures. Fibrosarcoma of the bone may be related to bone trauma such as bone infarcts, bone dysplasia, Paget's disease, chronic osteomyelitis, and bone irradiation.

After excision, local recurrence rates approach 60% but are reduced to 25% when postoperative radiation is used. The 5-year survival rate for patients with soft tissue fibrosarcomas is 40% to 60% in adults and 80% for the infantile form.

Pediatric Patient Considerations:
Congenital infantile fibrosarcoma usually occurs in children less than 2 years of age and has a better prognosis than the adult form. The t(12;15)(p13;q25) chromosomal translocation helps distinguish this fibrosarcoma from other fibrous lesions of childhood.


C49.9 – Malignant neoplasm of connective and soft tissue, unspecified

254748009 – Cutaneous fibrosarcoma

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

  • Nodular fasciitis – Rapidly growing, painful mass presenting especially on volar aspect of forearm.
  • Myositis ossificans – Presence of metaplastic bone, many times following an episode of trauma.
  • Osteosarcoma – Produces tumor osteoid.
  • Malignant neurosarcoma or malignant schwannoma – Malignancies of peripheral nerve sheaths.
  • Desmoid tumors – Histology shows a relative increase in collagen and absence of cytologic atypia.
  • Monophasic synovial sarcoma – Histology may show focal calcifications, gland or gland-like spaces.
  • Neurofibrosarcoma – Arises from an identifiable nerve; apparent neurofibroma components may be present.
  • Liposarcoma – Histology shows lipocytes in well-differentiated tumors, or lipoblasts if less well-differentiated.
Pediatric Patient Considerations:
  • Hemangioma – May be confused with a congenital infantile fibrosarcoma because of the possible presence of superficial ectatic veins in fibrosarcomas.
  • Rhabdomyosarcoma
  • Neuroblastoma
  • Primitive neuroectodermal tumors

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Last Updated:07/01/2020
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Fibrosarcoma - Skin
Fibrosarcoma (Fibrosarcoma of Bone) : Bone pain, Pathologic fracture, Limited range of motion
Clinical image of Fibrosarcoma
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