Desmoid-type fibromatosis in the head and neck: CT and MR imaging characteristics

In the head and neck region, desmoid-type fibromatosis is an uncommon tumor, and the imaging features have not been well described. The purpose of this study was to describe imaging features with their pathologic correlation of desmoid-type fibromatosis in this region.

Computed tomographic (CT) and magnetic resonance (MR) images of nine consecutive patients (five women and four men; age range, 2-72 years; mean age, 28 years) with desmoid-type fibromatosis in the head and neck were retrospectively evaluated, focusing on lesion location, size, shape, presence of a rim of surrounding fat, CT attenuation, signal intensity, and enhancement characteristics on MR with pathologic correlation.

Desmoid-type fibromatosis involved perivertebral space (n = 5) and carotid space (n = 1) in six adult patients. In three pediatric patients, the fibromatosis primarily involved submandibular space (n = 2) and masticator space (n = 1) with frequent invasion to the adjacent spaces (3/3). A mean greatest dimension of 5.8 cm, elongated shape (7/9), and rim of surrounding fat (8/9) were the common features of the desmoid-type fibromatosis. Tumors often showed iso (3/7) or high attenuation (3/7) on postcontrast CT, high signal intensity (6/9) on T2-weighted image, iso signal intensity (8/9) on T1-weighted image, and strong MR enhancement (8/9). Characteristic nonenhancing low signal intensity bands (8/9) on all MR sequences were well correlated with dense collagenous stroma.

Desmoid-type fibromatosis in the head and neck of adults frequently involves perivertebral space. Along with various common imaging features, desmoid-type fibromatosis shows characteristic nonenhancing low signal intensity bands on MR images.