Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Schwannoma
- Radiologic Findings
- Fig 1-2. Chest plain radiographs show mass in left lower lobe posterior portion.
Fig 3-6. On enhanced chest CT, about 4.8 x 3.5 cm sized, well-defined mass in left lower posterior hemithorax. The mass shows obtuse angle with the pleura and heterogeneous enhancement without accompanying rib destruction abutting with the mass.
- Brief Review
- Thoracic neurogenic tumors can originate from any nervous structure within the chest and are derived from cells of the autonomic ganglia, paraganglia or nerve sheath. The most common type of such nerve sheath tumors are Schwannomas, which originate from the spinal nerve root and extending along the intercostal nerve. Histologically, schwannomas consist of Schwann cells arranged in either a highly cellular distribution (Antoni A) or in a loose myxoid component (Antoni B), but both types may also be present in a single schwannoma.
Chest radiography of Schwannomas generally shows a smoothly marginated, oval paraspinal mass. In particular, contrast-enhanced CT shows a well-marginated paraspinal soft tissue mass with a possible “split fat” sign (fat attenuation around the soft-tissue mass). This is caused by displaced but intact surrounding fat covering the neuromuscular bundle, indicative of a non-filtrating underlying neurogenic mass. Schwannomas may also contain areas of low attenuation corresponding to fat or cystic degeneration. Calcification is seen in about 10% of Schwannoma cases, which may primarily be in a peripheral pattern, particularly in long-standing lesions with advanced degeneration. Osseous pressure erosion may also be present.
Meanwhile, MRI of Schwannomas cases shows low to intermediate signal intensity on T1-weighted images, high signal intensity on T2-weighted images, and intense enhancement of solid components on gadolinium-enhanced imaging.
- Please refer to
Case 120, Case 415, Case 1129, -
- References
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3. Geniets C, Vanhoenacker FM, Simoens W, Gielen J, De Schepper AM, Parizel PM. Imaging features of peripheral neurogenic tumors. JBR-BTR 2006; 89:216–219.
4. Subhawong TK, Fishman EK, Swart JE, Carrino JA, Attar S, Fayad LM. Soft-tissue masses and masslike conditions: what does CT add to diagnosis and management? AJR 2010; 194:1559–1567.
5. Lin J, Martel W. Cross-sectional imaging of peripheral nerve sheath tumors: characteristic signs on CT, MR imaging, and sonography. AJR 2001;176:75–82.
6. Sakai F, Sone S, Kiyono K, et al. Intrathoracic neurogenic tumors: MR-pathologic correlation. AJR 1992; 159:279–283.
- Keywords
- pleura, intercostal neurogenic tumor, schwannoma ,