tailieunhanh - Pediatric Chest Imaging - part 10

Hình 15. Một cậu bé 8 tuổi có u lympho Hodgkin. Tĩnh mạch tương phản hình ảnh tăng cường trục CT ngực cho thấy một khối lượng lớn trung thất trước và trung bình (mũi tên dày) với phần mở rộng vào thành ngực anteromedial trái (mũi tên mỏng). | IMAGING CHEST WALL DISORDERS IN CHILDREN 367 Fig. 15. An 8-year-old boy who has Hodgkin s lymphoma. Intravenous contrast-enhanced axial CT image of the chest shows a large anterior and middle mediastinal mass thick arrow with extension into the anteromedial left chest wall thin arrows . sectional imaging has become instrumental in the management of lymphoma. Demonstration of chest wall involvement may alter the radiation portals and administration of chemotherapy 64 . On CT lymphomatous extension of a large mediastinal mass often occurs in the parasternal region and appears as a fairly homogeneous soft tissue mass displacing normal structures of the chest wall and obliterating normal fat planes Fig. 15 . There may be lytic destruction of adjacent osseous structures such as ribs or sternum. Isolated chest wall involvement appears as homogeneous soft tissue masses deep to or within the pectoralis major and minor muscles 62 . Although CT has been the imaging modality most commonly used in the evaluation and staging of lymphoma MR imaging has also been shown to be sensitive to chest wall involvement. MR imaging demonstrates abnormal increased signal intensity on T2-weighted sequences in the region of the chest wall abnormality 65 66 . Other malignant soft tissue masses Other less common malignant soft tissue masses involving the chest wall in children include congenital fibrosarcoma malignant peripheral nerve sheath tumors mesenchymal chondrosarcoma neuroblastoma and osteosarcoma. Neuroblastoma can invade the chest wall by direct extension usually from the posterior mediastinum 67 . MR imaging is the best imaging modality to assess tumor extent and involvement of the neural foramina. These tumors demonstrate abnormal high signal intensity on T2-weighted sequences and show heterogeneous enhancement after administration of gadolinium 44 . Congenital fibrosarcoma also referred to as fibrosarcoma of infancy is a rare neoplasm that typically occurs in the axilla and thigh .