Dr. Francisco Bengoa
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Soft-tissue tumors

Infantile fibrosarcoma

Soft tissueIntermediate / locally aggressive or rarely metastasizingFibroblastic / myofibroblastic tumours

Epidemiology

A fibroblastic tumor of infants and young children, often congenital or diagnosed during the first year of life; the WHO 2020 classification places it among intermediate (rarely metastasizing) tumors. In infants it can grow considerably but respond to targeted treatment if an NTRK fusion is confirmed.

Basic features

It can grow quickly and ulcerate or affect function, but it usually has more favorable biology than adult fibrosarcomas.

Usual treatment

Management aims to preserve function: most cases carry the ETV6-NTRK3 fusion and, when an NTRK fusion is confirmed, TRK inhibitors (larotrectinib, entrectinib) achieve marked responses that allow the tumor to be shrunk and avoid amputations, very extensive resections or intensive chemotherapy; conservative surgery and chemotherapy are used depending on the case.

Outcomes and prognosis

Survival in localized disease is very good, and targeted therapies against the NTRK fusion have improved control; pediatric follow-up monitors function and recurrence.

Warning signs

These signs do not necessarily mean cancer, but they warrant evaluation before operating on or needling a mass.

  • A soft-tissue mass that grows, is larger than 5 cm, or is deep.
  • Persistent, night-time or progressive bone pain, especially if it limits activity.
  • A fracture from minimal trauma, or an aggressive bone lesion on an X-ray.
  • A lump that comes back after previous surgery.
  • Neurological symptoms, rapid swelling, or pain associated with a mass.

This information is general and does not replace a medical evaluation. A musculoskeletal tumor must be interpreted together with imaging, physical examination, biopsy when appropriate and each patient's context.

Specialist evaluation

If you have a mass, a bone lesion or a report suggesting a tumor, book an evaluation.

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