QUIZ: No. 23, 09/08/2025

NCCT

MRI

ANS – Desmoid fibromatosis

Desmoid fibromatosis of the tensor fascia lata typically presents as a well-defined, lobulated soft tissue mass arising from or straddling the fascia lata, located both superficial and deep to the tensor fascia lata. On MRI, it appears iso- to hypointense on T1-weighted images and shows homogeneous or slightly heterogeneous avid enhancement on post-contrast sequences. The lesion commonly demonstrates low to intermediate signal on T2, often with internal low-signal fibrous bands. A key imaging clue is its fascial-based growth pattern, infiltrating or tracking along the aponeurotic plane without overt necrosis or hemorrhage, helping distinguish it from soft tissue sarcomas or myxoid tumors.

Take home points

1.     Fascial-based, dual-compartment (superficial and deep) location and lack of aggressive bony destruction—favour a diagnosis of desmoid fibromatosis.

2.     Internal T2 low-signal fibrous bands are a characteristic of desmoid fibromatosis