RETURN TO ABSTRACT LISTING


Background
Fibroblastic and myofibroblastic tumors (FMTs) represent a group of related soft tissue neoplasms derived from mesenchymal stem cells that subsequently differentiate into fibroblasts, and/or myoblasts/myocytes that differentiate into muscle cells. The World Health Organization (2020) classifies tumors as being FMTs based on their imaging appearance, histology, and newly discovered abnormalities in the gene expression.

Educational Goals / Teaching Points
The learning objectives are to recognize the common FMTs and identify the typical imaging features of this related group of soft tissue neoplasms.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
FMTs are classified in four tumor categories based on their varying levels of aggressiveness, benign, intermediate (locally aggressive), intermediate (rarely metastasizing), and malignant. The largest category is benign FMTs and includes such entities as nodular fasciitis, proliferative myositis, myositis ossificans, elastofibroma, fibroma of tendon sheath, cellular angiofibroma, and mammary-type myofibroblastoma. Intermediate category FMTs are divided into locally aggressive and rarely metastasizing groups. The locally aggressive FMTs include desmoid tumors and palmar/plantar fibromatosis. The rarely metastasizing FMTs include dermatofibrosarcoma protuberans and solitary fibrous tumor. The malignant MFTs include fibrosarcoma, myxofibrosarcoma, low grade fibromyxoid sarcoma, and malignant solitary fibrous tumor.

Conclusion
FMTs are a group of related soft tissue neoplasms that are classified based on their imaging appearance, histology, and newly discovered abnormalities in the gene expression. This exhibit will explore the various forms of FMT and delineate the differing but related imaging and histopathologic appearances of these intriguing soft tissue lesions.