Desmoid fibromatosis (DF) may be sporadic or familial in nature. Patients with familial adenomatous polyposis and Gardner syndrome are at an increased risk of developing desmoid tumors.

DF may be sporadic or familial in nature. Familial cases usually develop intra-abdominal or abdominal wall tumors, contrasted to the sporadic cases, which usually tend to develop aggressive extra-abdominal desmoids. 

The etiology is not well understood, believed to be related to various genetic or hormonal factors, as well as previous trauma and surgery.

Aggressive fibromatosis usually originates from muscular connective tissues, aponeurosis or fascia, such as in this case. 

They are benign locally aggressive tumors with no metastatic affinity. Given their infiltrative aggressive nature, incomplete surgical resection is a common problem, resulting in high local recurrence rates. 

FDG PET/CT does not particularly aid in differentiating malignant from benign soft tissue tumors. Desmoid tumors may show variable degrees of uptake.