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.

MRI of children with OCD consistently showed secondary physis disruption, overlying chondroepiphysial widening, and subchondral bone edema. We suggest that disruption of normal endochondral ossification may be associated with juvenile OCD.

On knee MRI, a FOPE zone can be seen in adolescents and likely relates to the early stages of physiologic physeal closure. It may be associated with pain particularly when no other MRI abnormalities are present. When the characteristic appearance of a FOPE zone is observed on MRI, we suggest that it not be mistaken for an abnormality, requires no invasive diagnostic procedure, and does not need imaging follow-up.

Rotator cuff tears can be identified during MRI examination of symptomatic child and adolescent shoulders and often consist of tear patterns associated with repetitive microtrauma in overhead athletic activities or with single traumatic events. Rotator cuff tears are seen throughout the range of skeletal maturity, often coexist with labral tears and typically are found in athletes.