Desmoid tumors are classified as extra-abdominal, intra-abdominal, or located within the abdominal wall. Abdominal wall desmoid tumors arise most commonly from the aponeurosis of the rectus abdominus muscle with out without intraabdominal extension.. Extra-abdominal tumors typically occur in the shoulder, chest wall, thigh, inguinal region, and back. Clinical symptoms are masked by the slow growth of the tumor and depend on the site to tumor involvement.
Desmoid tumors have a similar attenuation to muscle on contrast-enhanced CT images. However, CT cannot distinguish a desmoid tumor from similar soft tissue tumors, making histological diagnosis necessary. MRI enables better tissue characterization of desmoid tumors by demonstrating intratumoral areas of low signal intensity on all pulse sequences. The low signal intensity is due to the presence of abundant collagen within the lesion. Desmoid tumors appear as low-signal intensity masses in a background of high-signal intensity fat on T1-weighted MR images. These tumors have variable signal intensity on T2-weighted MR images. In mature desmoids, areas of abundant fibrosis results in low signal intensity on T2-weighted images. Longstanding tumors are low in signal intensity on T1 and T2-weighted MR images and enhance only minimally after intravenous gadolinium chelate. In the acute phase, tumors may have regions of high signal intensity on T2-weighted images that also show heterogeneous increased enhancement. Tumor recurrence is a frequent finding after surgery and is easily detected using MRI.
Desmoid tumors have a similar attenuation to muscle on contrast-enhanced CT images. However, CT cannot distinguish a desmoid tumor from similar soft tissue tumors, making histological diagnosis necessary. MRI enables better tissue characterization of desmoid tumors by demonstrating intratumoral areas of low signal intensity on all pulse sequences. The low signal intensity is due to the presence of abundant collagen within the lesion. Desmoid tumors appear as low-signal intensity masses in a background of high-signal intensity fat on T1-weighted MR images. These tumors have variable signal intensity on T2-weighted MR images. In mature desmoids, areas of abundant fibrosis results in low signal intensity on T2-weighted images. Longstanding tumors are low in signal intensity on T1 and T2-weighted MR images and enhance only minimally after intravenous gadolinium chelate. In the acute phase, tumors may have regions of high signal intensity on T2-weighted images that also show heterogeneous increased enhancement. Tumor recurrence is a frequent finding after surgery and is easily detected using MRI.
Second opinion by- Teleradiology Providers
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