Clinical and imaging features of desmoid tumors of the extremities

Abstract

BACKGROUND Desmoid fibroma is a rare soft tissue tumor originating from the aponeurosis, fascia, and muscle, and it is also known as aponeurotic fibroma, invasive fibroma, or ligamentous fibroma. AIM To investigate the clinical and imaging features of desmoid tumors of the extremities. METHODS Thirteen patients with desmoid fibroma of the extremities admitted to our hospital from October 2016 to March 2021 were included. All patients underwent computed tomography (CT), magnetic resonance imaging (MRI), and pathological examination of the lesion. Data on the diameter and distribution of the lesion, the relationship between the lesion morphology and surrounding structures, MRI and CT findings, and pathological features were statistically analyzed. RESULTS The lesion diameter ranged from 1.7 to 8.9 cm, with an average of 5.35 ± 2.39 cm. All lesions were located in the deep muscular space, with the left and right forearm each accounting for 23.08% of cases. Among the 13 patients with desmoid fibroma of the extremities, the lesions were "patchy" in 1 case, irregular in 10, and quasi-round in 2. The boundary between the lesion and surrounding soft tissue was blurred in 10 cases, and the focus infiltrated along the tissue space and invaded the adjacent structures. Furthermore, the edge of the lesion showed "beard-like" infiltration in 2 cases; bone resorption and damage were found in 8, and bending of the bone was present in 2; the boundary of the focus was clear in 1. According to the MRI examination, the lesions were larger than 5 cm (61.54%), round or fusiform in shape (84.62%), had an unclear boundary (76.92%), showed uniform signal (69.23%), inhomogeneous enhancement (84.62%), and "root" or "claw" infiltration (69.23%). Neurovascular tract invasion was present in 30.77% of cases. CT examination showed that the desmoid tumors had slightly a lower density (69.23%), higher enhancement (61.54%), and unclear boundary (84.62%); a CT value < 50 Hu was present in 53.85% of lesions, and the enhancement was uneven in 53.85% of cases. Microscopically, fibroblasts and myofibroblasts were arranged in strands and bundles, without obvious atypia but with occasional karyotyping; cells were surrounded by collagen tissue. There were disparities in the proportion of collagen tissue in different regions, with abundant collagen tissue and few tumor cells in some areas, similar to the structure of aponeuroses or ligaments, and tumor cells invading the surrounding tissues. CONCLUSION Desmoid tumors of the extremities have certain imaging features on CT and MRI. The two imaging techniques can be combined to improve the diagnostic accuracy, achieve a comprehensive diagnosis of the disease in the clinical practice, and reduce the risk of missed diagnosis or misdiagnosis. In addition, their use can ensure timely diagnosis and treatment.

Multimodality Imaging Assessment of Desmoid Tumors: The Great Mime in the Era of Multidisciplinary Teams

“…Shi et al evaluated the imaging features in 13 patients with desmoid fibroma of the extremities, finding that the tumors showed a lower density (69.23%), a higher degree of enhancement (61.54%) and unclear boundaries (84.62%) ( Figure 3 ); a CT value < 50 Hu was encountered in 53.85% of lesions, and the enhancement was uneven in 53.85% of cases [ 137 ].…”

“…CT and MRI allow us to characterize the lesion and to determine the relationship between lesions and surrounding organs for proper treatment planning. During CT study, the lesion density is uniform with uniform enhancement during the contrast study [ 80 , 137 ]. These features are not typically for gastrointestinal stromal tumors, lymphoma, neuroendocrine tumors and/or carcinoma, which show inhomogeneous density due to necrosis or for hormonal mesenteric reaction [ 80 , 137 ].…”

“…During CT study, the lesion density is uniform with uniform enhancement during the contrast study [ 80 , 137 ]. These features are not typically for gastrointestinal stromal tumors, lymphoma, neuroendocrine tumors and/or carcinoma, which show inhomogeneous density due to necrosis or for hormonal mesenteric reaction [ 80 , 137 ]. In addition, DTs have several typical features on MRI evaluation, such as a star shape and extension into the fascial planes and fat tissue in a sunburst-like form, with homogeneous signal isointense in T1-W and hyperintense in T2-W [ 80 ].…”

“…), occurring in extremities, head and neck and trunk, may mimic these entities. During CT studies, DTs of the extremities show a low density, mild enhancement and unclear boundary [ 137 ]. In MRI studies, typical features are a round or fusiform shape, unclear boundaries, uniform signals, uneven enhancement, “tree root” or “claw” infiltration and invasion of the neurovascular bundles [ 137 ].…”

“…During CT studies, DTs of the extremities show a low density, mild enhancement and unclear boundary [ 137 ]. In MRI studies, typical features are a round or fusiform shape, unclear boundaries, uniform signals, uneven enhancement, “tree root” or “claw” infiltration and invasion of the neurovascular bundles [ 137 ]. Conversely to them, malignant soft tissue tumors show inhomogeneous T1-W and T2-W signals, and the T2 signal intensity is higher than fat signal, with calcifications or cystic necrosis [ 183 , 184 ].…”