From the archives of the AFIP: musculoskeletal fibromatoses: radiologic-pathologic correlation.

Musculoskeletal fibromatoses represent a wide spectrum of fibroblastic and myofibroblastic neoplasms with similar pathologic appearances and variable clinical behavior. These lesions can be categorized by location (superficial or deep) or by the age group predominantly affected. Superficial fibromatoses in adults (palmar and plantar) and children (calcifying aponeurotic fibroma, lipofibromatosis, and inclusion body fibromatosis) are often small slow-growing lesions; their diagnosis is suggested by location. Deep fibromatoses in adults (desmoid type and abdominal wall) and children (fibromatosis colli and myofibroma and myofibromatosis) are frequently large and more rapidly enlarging; location of these lesions may be nonspecific. Radiographic findings typically are nonspecific. Cross-sectional imaging (ultrasonography, computed tomography, or magnetic resonance [MR] imaging) reveals lesion location, extent, and involvement of adjacent structures for staging and evaluation of local recurrence. MR imaging findings of predominantly low to intermediate signal intensity, nonenhancing bands of low signal intensity on long repetition time MR images that represent collagenized regions, and extension along fascial planes ("fascial tail" sign) add specificity for diagnosis. Additional features that aid in diagnostic specificity include an abdominal wall location related to pregnancy (abdominal wall fibromatosis), a lower neck location in a young child (fibromatosis colli), an adipose component (lipofibromatosis), or multiple lesions in young children (myofibromatosis). Treatment may be conservative or surgical resection, depending on the specific diagnosis. Local recurrence is common after surgical resection owing to the infiltrative growth of these lesions. Recognition that the appearances of the various types of musculoskeletal fibromatoses reflect their pathologic characteristics improves radiologic assessment and helps optimize patient management.