New concepts in understanding evolution of desmoid tumors: MR imaging of 30 lesions

Abstract

The objective of this study was to evaluate the appearance and the natural evolution of desmoid tumors on MR imaging, given histologic correlation. The MR images of 30 desmoids (20 primary and 10 recurrent) in 26 patients were scored for a multiplicity of morphological parameters, signal intensity (SI) on different pulse sequences, and behavior after contrast administration. Natural evolution was evaluated in 2 primary and 3 recurrent lesions, and correlated with evolution on histologic specimens. Desmoid tumors are mostly found in muscles of shoulder and hip girdle and are often fusiform with partially ill-defined margins. Rare subcutaneous desmoids have a more stellar morphology. Variable amounts of low-SI areas are present on all sequences. On T1-weighted images (T1-WI), most lesions are near homogeneous and isointense to muscle, whereas on T2-WI they are more heterogeneous with an overall SI equal to or slightly lower than fat. Histologic correlation reveals that SI on T2-WI cannot be explained solely by cellularity. After initial growth, spontaneous evolution of desmoids is characterized by shrinking and an increase in low-SI areas on T2-WI. While distal lesions shrink, the more recent lesions in asynchronous multicentric desmoids have a tendency to develop proximally in the same limb, and should not be confused with recurrences. Fast growth, extracompartmental spread, and bone involvement are often seen in recurrences. Follow-up MR imaging of desmoids indicates natural regression of desmoids and more aggressive behavior of recurrences, which may justify a more conservative therapeutic approach.

Management of desmoid-type fibromatosis involving peripheral nerves

“…On CT scans, the lesion appears hyperattenuated with significant enhancement after contrast injection 11 . In MRI, the lesion appears hypointense to isointense relative to muscle on T1-weighted imaging, and with a signal intensity similar to fat on T2-weighted images 12 .…”

Extraabdominal desmoid tumors

“…Desmoid tumors of the deep structures are described as having a fusiform appearance, with subcutaneous tumors being more stellate in nature. 23 On computed tomography scans, the lesion appears hyperattenuated with significant enhancement after the application of contrast material. 1 Magnetic resonance imaging characteristics include a lesion that is hypointense to isointense relative to muscle on T1-weighted imaging, and with a signal intensity similar to fat on T2-weighted images 23 ( Fig.…”

The Imaging Features of Desmoid Tumors: the Usefulness of Diffusion Weighted Imaging to Differentiate between Desmoid and Malignant Soft Tissue Tumors

“…However, the imaging findings of desmoid tumors reported thus far are very diverse and often similar to those of malignant tumors in signal intensity (SI), tumor margination, and in the tendency to encase adjacent organs (12)(13)(14). Therefore, the diagnosis of desmoid tumors is a challenge for both radiologists and clinicians.…”