Angiofibroma of soft tissue
Angiofibromas of soft tissue are benign fibroblastic soft tissue neoplasms permeated by a vascular network that might be found in the periarticular and articular areas of the lower extremities that have been included as a separate entity into the WHO classification of soft tissue tumors in 2020.
Angiofibromas of soft tissue tumors are mostly found in the middle-aged population with a peak incidence in the sixth decade and a slight female predominance. They can generally affect patients of all ages 1.
The typical clinical presentation is a slow-growing soft tissue mass 1.
Angiofibromas of soft tissue are characterized by uniform and spindle cells in a fibromyxoid matrix permeated innumerable small thin-walled blood vessels 1.
The etiology of angiofibroma of soft tissue is unknown 1.
Soft tissue angiofibromas are usually found in the extremities in particular the lower extremity with a periarticular articular involvement, a subcutaneous or less often intramuscular or deep location. Unusual sites of origin are the back, abdominal wall the pelvis and breast 1-4.
Macroscopically angiofibromas of soft tissue are usually solid nodular or multinodular well-delineated tumors with a shimmering cut surface and a white to yellowish color 1,4.
Histologically angiofibromas of soft tissue include the following microscopic features 1-4:
- uniform bland spindle cells with regional variations in cellularity
- variable myxoid to collagenous extracellular matrix
- prominent vascular network
- variable inflammatory infiltrates
- no cytological atypia or nuclear hyperchromasia
Angiofibromas of soft tissue are associated with NCOA2 gene rearrangements 1-4.
Dedicated descriptions of imaging appearances of angiofibroma of soft tissue are still scarce in the literature. A few reports have described it as a well-circumscribed mass. Signal characteristics and enhancement are presumed to be variable subject to the cellular, myxoid, collageneous and vascular content of the lesion 3,4.
- T1: roughly isointense to skeletal muscle
- T2: heterogeneous high signal intensity
- T1C+(Gd): variable from homogeneous to a peripheral enhancement
The radiological report should include a description of the following:
- form, location and size
- tumor margins and transition zone
- relation to adjacent joints
- relation to adjacent neurovascular structures
Treatment and prognosis
Angiofibromas of soft tissue are benign lesions with a benign clinical course. They have rare local recurrences after excision and there is no known risk for metastases 1,3.
History and etymology
Angiofibroma of soft tissue is a fairly newly described tumor entity by Adrián Mariño-Enríquez and Christopher DM Fletcher in 2012 3-5.
Tumors or conditions which can mimic the presentation and/or appearance of angiofibroma of soft tissue include 3,4:
- 1. W.H.O. Classification WHO Classification of Tumours Editorial Board, Who Classification of Tumours Editorial. Soft Tissue and Bone Tumours. (2020) ISBN: 9789283245025
- 2. Kallen ME, Hornick JL. The 2020 WHO Classification: What's New in Soft Tissue Tumor Pathology?. (2021) The American journal of surgical pathology. 45 (1): e1-e23. doi:10.1097/PAS.0000000000001552 - Pubmed
- 3. Hashino Y, Nishio J, Maeyama A, Aoki M, Nabeshima K, Yamamoto T. Intra-articular angiofibroma of soft tissue of the knee: A case report. (2017) Molecular and clinical oncology. 7 (2): 229-232. doi:10.3892/mco.2017.1298 - Pubmed
- 4. Zhao M, Sun K, Li C, Zheng J, Yu J, Jin J, Xia W. Angiofibroma of soft tissue: clinicopathologic study of 2 cases of a recently characterized benign soft tissue tumor. (2013) International journal of clinical and experimental pathology. 6 (10): 2208-15. Pubmed
- 5. Mariño-Enríquez A, Fletcher CD. Angiofibroma of soft tissue: clinicopathologic characterization of a distinctive benign fibrovascular neoplasm in a series of 37 cases. (2012) The American journal of surgical pathology. 36 (4): 500-8. doi:10.1097/PAS.0b013e31823defbe - Pubmed