Citation, DOI & article data
Adult fibrosarcomas are rare, malignant and highly aggressive fibroblastic soft tissue tumors. They constitute a diagnosis of exclusion.
Adult fibrosarcomas by more recent definition are rare and make up around 1% of soft tissue sarcomas. They are mostly seen in middle-aged people within the 4th and 7th decade of life and with a minor male predilection 1-3.
Adult fibrosarcomas have been associated with radiation therapy and foreign implants 1,2.
The diagnosis of adult fibrosarcomas is established histologically. It is a diagnosis of exclusion 1,2,4.
Diagnostic criteria of adult fibrosarcoma according to the WHO classification of tumors: soft tissue and bone (5th edition) 1:
- monomorphic spindle cell with not more than moderate nuclear polymorphism
- herringbone or fascicular growth pattern with variable amounts of collagen
- immunohistochemical and molecular exclusion of other diagnoses
The typical complaint is a soft tissue mass, which can present with or without pain 1,2.
Adult fibrosarcomas have become a diagnosis of exclusion. They are characterized by relatively monomorphic spindle cells growing in a fascicular pattern with variable collagen production also referred to as herringbone architecture 1.
The etiology is unclear some adult fibrosarcomas have been found in the field of previous radiation therapy.
Locations, where adult fibrosarcomas are mostly found, include the deep soft tissues underneath the deep fascia of the extremities, the trunk and the head and neck region 1-3.
Macroscopically adult fibrosarcoma usually appears as a circumscribed tumor of tannish white color and firm consistency sometimes featuring areas of necrosis and/or hemorrhage 1,2.
Microscopic features of adult fibrosarcoma include the following 1:
- relatively monomorphic spindle cells (no high degree of pleomorphism)
- fascicular growth in a ‘herringbone’ architecture
- variable collagen production
- variable mitotic activity
- areas of necroses
Imaging features of adult fibrosarcomas have been described as lobulated, well-defined lesions with fibrous bands and slightly irregular margins as well as relations to the deep fasciae with nodular lumps around the fascia edge 2,3. They displace the surrounding tissues 2.
The CT appearance of adult fibrosarcomas has been described as a soft tissue density mass usually isodense to muscle 2.
On MRI adult fibrosarcomas have been described to look like a heterogeneous soft tissue mass with low signal intensity band-like fibrous streaks in all sequences. Changes in the deep fascia and associated muscle edema have been described in a higher number of cases 3.
Signal characteristics are usually as follows 2,3,5:
- T1: hypo- to isointense to muscle
- T2: mixed heterogeneous hyperintense signal intensity
- DWI: diffusion restriction
- T1 C+ (Gd): variable, heterogeneous peripheral or spoke wheel enhancement
The radiological report should include a description of the following 3:
- form, location and size
- tumor margins
- relation to and alterations of the muscular fascia
- relationship to local nerves and vessels
- subcutaneous tissue or bony involvement
Treatment and prognosis
Treatment options include surgery complemented by adjuvant radiotherapy and neoadjuvant chemotherapy. Local recurrence depends on tumor residues upon surgical removal. Distant metastases occur in the lung liver and bones, in particular, the axial skeleton. Lymph node metastases are rare. The 5-year survival is around 50% 1-3.
History and etymology
Adult fibrosarcoma was once regarded as the most common soft tissue sarcomas in adults 1. Due to advances in testing methods and changes in diagnostic criteria they have become rare entities and a diagnosis of exclusion 1,2. Many descriptions of ‘fibrosarcomas’ have been made in the 1930s and 1940s of which lesions a high percentage would not fulfill diagnostic requirements according to current standards 6-8.
Conditions that can mimic the presentation and/or the appearance of adult fibrosarcoma include the following 1-4:
- 1. Yoshida A, Folpe AL. Adult fibrosarcoma. In: WHO Classification of Tumours Editorial Board. Soft tissue and bone tumours. Lyon (France): International Agency for Research on Cancer; 2020. (WHO classification of tumours series, 5th ed.; vol. 3). https://publications.iarc.fr
- 2. Augsburger D, Nelson P, Kalinski T et al. Current Diagnostics and Treatment of Fibrosarcoma -Perspectives for Future Therapeutic Targets and Strategies. Oncotarget. 2017;8(61):104638-53. doi:10.18632/oncotarget.20136 - Pubmed
- 3. Wang H, Nie P, Dong C et al. CT and MRI Findings of Soft Tissue Adult Fibrosarcoma in Extremities. BioMed Research International. 2018;2018:1-7. doi:10.1155/2018/6075705 - Pubmed
- 4. Bahrami A & Folpe A. Adult-Type Fibrosarcoma: A Reevaluation of 163 Putative Cases Diagnosed at a Single Institution over a 48-Year Period. Am J Surg Pathol. 2010;34(10):1504-13. doi:10.1097/PAS.0b013e3181ef70b6 - Pubmed
- 5. Sedaghat S, Schmitz F, Krieger A, Sedaghat M, Reichardt B. Appearance of Recurrent Adult Fibrosarcoma of the Soft Tissue and Loco-Regional Post-Treatment Changes on MRI Follow-Up. Eur J Plast Surg. 2020;44(1):97-102. doi:10.1007/s00238-020-01669-1
- 6. Stout A. Fibrosarcoma the Malignant Tumor of Fibroblasts. Cancer. 1948;1(1):30-63. doi:10.1002/1097-0142(194805)1:1<30::aid-cncr2820010104>3.0.co;2-d - Pubmed
- 7. French R. End-Results in a Series of Sixteen Cases of Fibrosarcoma. N Engl J Med. 1932;206(8):393-5. doi:10.1056/nejm193202252060804
- 8. Meyerding HW, Broders AC, Hargrave RL (1936) Clinical aspects of fibrosarcoma of the soft tissues of the extremities. Surg Gynecol Obstet 62:1010–1019