infantiles Fibrosarkom
Infantile fibrosarcomas are locally aggressive rarely metastasizing fibroblastic tumors found in the pediatric population.
Terminology
Other acceptable terms include congenital fibrosarcoma, infantile fibrosarcoma-like tumor, cellular congenital mesoblastic nephroma .
Epidemiology
Infantile fibrosarcomas are most commonly found in the first two years of life with more than 75% of the cases found during the first year and at birth and further 15% in the second year of life . A bit less than 15% are already detected at prenatal ultrasound .
Associations
There is a relation to congenital mesoblastic nephroma .
Clinical presentation
The typical manifestation is a rapidly growing painless mass or nodule, they may look like a vascular tumor and ulcerate .
Pathology
Infantile fibrosarcomas are locally aggressive tumors characterized by spindle cells or primitive ovoid cells often growing in a fascicular or herringbone architecture with a staghorn vascular pattern, mixed inflammatory changes and .
Location
Infantile fibrosarcomas are usually found in the superficial and deep soft tissues of the following locations :
- extremities
- trunk
- head and neck region
Less commonly it is found in the abdomen or retroperitoneum and rarely it involves the bones and viscera such as the lung and the bowel .
Macroscopic appearance
Macroscopically infantile fibrosarcomas usually appear as poorly circumscribed lobulated tumors with infiltrative boundaries, some feature a pseudocapsule. They can be quite large when discovered. .
Microscopic appearance
The microscopic spectrum of infantile fibrosarcoma is broad and includes the following :
- monomorphic spindle cells to ovoid/round cells
- fascicular growth in a ‘herringbone’ architecture
- collagenous or myxoid background
- hemangiopericytoma-like vascular pattern
- mixed chronic inflammatory infiltrates
- variable mitotic activity
- frequently zonal necrosis and/or hemorrhages
Immunohistochemistry
Immunohistochemistry stains are non-specific and can display expressions of SMA, CD34, S100 or desmin .
Genetics
Infantile fibrosarcoma often displays an ETV6-NTRK3 gene fusion or rearrangement .
Radiographic features
Imaging findings usually reveal a nonspecific heterogeneous mass with signs of intralesional hemorrhage .
Ultrasound
Ultrasound usually reveals a heterogeneous isoechoic, hypervascular mass with dilated vessels sometimes looking a bit like hemangioma .
MRI
On MRI infantile fibrosarcomas are heterogeneous soft tissue masses and can show well-defined or infiltrative tumor margins. They might show low signal intensity fibrous streaks . They might show with intralesional signal voids due to vasculature and hemorrhagic components, being hyperintense in both T1 weighted and T2 weighted images .
Signal characteristics are usually as follows:
- T1: generally hypo- to isointense to muscle
- T2: generally hyperintense signal intensity
- T1 C+ (Gd): heterogeneous predominantly peripheral enhancement
Radiology report
The radiological report should include a description of the following:
- form, location and size
- tumor margins
- relation to the muscular fascia
- relationship to local nerves and vessels
- relations to other organs
Treatment and prognosis
Treatment options include combinations of surgery and chemotherapy. Local recurrence occurs in up to 40% and is especially associated with incomplete resection. Metastases occur rarely and most often affect the lungs. The 10-year survival is about 90% with standard therapy .
Differential diagnosis
Conditions which can mimic the presentation and/or the appearance of infantile fibrosarcoma include :
- adult fibrosarcoma
- infantile fibromatosis
- myofibromatosis
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Assoziationen und Differentialdiagnosen zu infantiles Fibrosarkom:
