MRI characterization of the peripheral neurogenic tumours

Transcription

1 MRI characterization of the peripheral neurogenic tumours Poster No.: C-3375 Congress: ECR 2010 Type: Scientific Exhibit Topic: Neuro Authors: M. Bertomeu, C. Montull, J. Peri, A. Roma, A. Moreno, C Julià ; Barcelona/ES, Badalona/ES Keywords: Neurofibroma, Schwannoma, MRI DOI: /ecr2010/C-3375 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 35

2 Purpose MR provides a well established method in the diagnosis of the peripheral neurogenic tumours. Distinction between schwannomas and neurofibromas in MR is possible by evaluating their morphology and signal characteristics. Peripheral nerves are derived embriologycally from neural crest tissue and migrating axons from the primitive neural tube. Each peripheral nerve is surrounded by a thick connective tissue sheath called the epineurium. Within the nerve, groups of axons are surrounded and divided by a fibrous stroma called the perineurium. Vascular suply to the peripheral nerves is relatively profuse, arises from adjacent vessels, and forms longitudinally oriented channels along the nerve(fig. 1) The hiystological difference between two principals tumours : Schwannomas, originates within a Schwann cell cylinder that surrounds an axon, the tumor grows eccentrally compressing the normal adjacent axons (FIG.2) Neurofibromas, the endoneurium increases in volume. The tumoral matrix is a complex of Schwann cells, axons, and fibrous material, surrounded by a thickened perineurium (FIG. 3) In 1920, Nils Ragnar Augène Antoni ( ), a swedish neurologist and researcher described 2 distinct patterns of cellular architecture in the peripheral nerve sheath tumors, wich would become known as Schwannomas. These patterns: Antoni A and Antoni B fibers ( FIG. 4-5). Advances in molecular and cellular biology have generated significant evidence indicating that Schwann cells are the cell origin for both schwannomas and neurofibromas. Page 2 of 35

3 Images for this section: Fig. 1: Diagram of a Schwannoma. The tumor (T) grows eccentrically compressing the normal adjacent axons. Fig. 2: Diagram of a neurofibroma The endoneurium increases in volume. The tumoral matrix is a complex of Schwann cells, axons, and fibrous material and surrounded by a thichkened perineurium. Page 3 of 35

4 Fig. 3: AP findings Antoni A and Antoni B fibers Schwannoma 18 years old. Submandibular painless mass. Page 4 of 35

5 Fig. 4: Macroscopic piece Size: 4 cm. 18-years-old man with painless submandibular mass. Schwannoma Page 5 of 35

6 Methods and Materials A retrospective multi-centric study was performed. 50 patients with peripheral neurogenic tumours diagnostic by MRI and posterior hystological confirmation (45%). The MR studies were performed in three different equipment 1,5 T (GE excite, GE and SIEMENS). All MR examinations were performed with FSE T2 sequences in three plane, SE T1, STIR sequences, and SE T1 fat-sat after gadolinium administration. A previous US study has been done in 60% of the cases. We have considered the enhancement pattern by echo-doppler, in two types: matrix tumoral enhancement (FIG. 1) and tail enhancement (FIG. 2). We have analyzed the shape (fusiform, dumbbell or ovoid), the deep (superficial or deeper), the size (< or > 5cm), the signal patterns by MRI( T2W images : target sign, fascicular appearance, thin hyperintense rim, chystic areas) (FIG. 3), and the enhancement pattern by MRI (central, diffuse and peripheral) and echo-doppler ( matrix tumoral enhancement and tail enhancement) of the peripheral neurogenic tumors. The target sign and the split-fat sign are commun in both types of tumor. Pain and neurologic symptoms (dysesthesias, paresthesias) are unusual except in large tumors (> 5cm) (FIG. 4-5). Images for this section: Page 6 of 35

7 Fig. 1: 34-years-old-man with a pain mass tibial posterior nerve. Matrix tumoral enhancement by echo-doppler. Size: 4,5cm. Superficial, subcutaneous. Chystic area inside the tumour. Page 7 of 35

8 Fig. 2: 34-years-old-man with a pain mass tibial posterior nerve. Tail enhancement by echo-doppler. Size: 3cm superficial, subcutaneous. Page 8 of 35

9 Fig. 3: 34-years-old-man with a pain mass tibial posterior nerve. Axial plane T2W image. Size: 4,5cm Superficial, subcutaneous. Axial plane MRI Chystics areas, hyperintenses areas in T2W images. Suggest Neurofibroma. Page 9 of 35

10 Fig. 4: 53-years-old-man with a pain large mass (>5cm) in the left gluteus zone (left sciatic nerve). Neurofibroma. Sagittal plane T1 FS Gd+. Dishomogeneous enhancement. Page 10 of 35

11 Fig. 5: 53-years-old-man with a pain large mass (>5cm) in the left gluteus zone (left sciatic nerve). Neurofibroma. US: Dishomogeneous. Page 11 of 35

12 Results The morphology, signal characteristics, enhancement pattern of the lesion can contribute to distinguish between two principals groups of peripheral neurogenic tumours (Schwannoma and Neurofibroma). This differentiation is important to determine and to plan the treatment. For Schwannomas, marginal excision can usually spare the nerve because the tumour is generally separable from the underlying nerve, and the function to be preserved.(fig. 1) For Neurofibromas, a resection of the nerve with the tumor is necessary because is not possible to separate the nerve fibers of the tumor. This conditione the nerve function loss. Differentiation of both can help the surgeon determine the preoperative plan. The hiystological difference between two principals tumours : Schwannomas, originates within a Schwann cell cylinder that surrounds an axon, the tumor grows eccentrally compressing the normal adjacent axons In our review and monitoring, we found only post-surgical confirmation in 45% of cases because it involved only tumours with syntoms (pain, abnormal sensitivity...) and a majority are silent. Antoni A and Antoni B fibers (is a pattern of recognition in the histologic identification of Schwannomas. (FIG. 1 to 9) Neurofibromas contains all the cellular elements of a peripheral nerve, including Schwann cells, fibroblasts, perineurial cells and axons. The tumor cells grow duffusely within and along nerves, and expand radially while entrapping neural elements within the tumor. (FIG. 10 to 18) Images for this section: Page 12 of 35

13 Fig. 1: Tm in the radial nerve right arm. Coronal section WT1 fat-sat Gd+. Dishomogeneous enhancement pattern. Painless mass. AP. Schwnnoma. Page 13 of 35

14 Fig. 2: Coronal plane T2W Radial nerve tumour Central hypointense area Tail identified Page 14 of 35

15 Fig. 3: 35-years-old man with a painless mass in the tibial anterior nerve. Sagittal plane in T1W image. Well defined lession intermediate signal with a hypointense nodule inside. Page 15 of 35

16 Fig. 4: 35-years-old man with a painless mass in the tibial anterior nerve. Sagittal plane MRI STIR. Heterogeneous hyperintensity. Schwannoma Page 16 of 35

17 Fig. 5: 35-years-old man with a painless mass in the tibial anterior nerve. Sagittal plane T1 Fat sat Hypointense nodule inside the tumor. Page 17 of 35

18 Fig. 6: 35-years-old man with a painless mass in the tibial anterior nerve. Sagittal plane T1 fat-sat Gd+ Enhancement by the nodule inside the tumor. Page 18 of 35

19 Fig. 7: 35-years-old man with a painless mass in the tibial anterior nerve. Dishomogeneous mass. Page 19 of 35

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21 Fig. 8: 35-years-old man with a painless mass in the tibial anterior nerve. Sagittal plane MRI. Hypointense nodule inside the tumor, in T1W image. Fig. 9: 35-years-old man with a painless mass in the tibial anterior nerve. Tail enhancement by echo-doppler. Page 21 of 35

22 Fig. 10: 43-years-old-man with a pain mass in the right palmar hand. Coronal plane Intermediate signal in T1W image Page 22 of 35

23 Fig. 11: 43-years-old-man with a pain mass in the right palmar hand. Coronal plane T1W fat-sat intermediate signal lession in the right palmar hand. Page 23 of 35

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25 Fig. 12: 43-years-old-man with a pain mass in the right palmar hand. Sagittal plane T1W fat-sat Gd+ Heterogeneous enhancement. Page 25 of 35

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27 Fig. 13: 43-years-old-man with a pain mass in the right palmar hand. Sagittal plane T1W fat-sat Gd+ Heterogeneous enhancement Fig. 14: 63-years-old-man with a pain mass in the tibial posterior nerve. Sagittal plane MRI T1w fat-sat Heterogeneous lession with hypointense tracts Page 27 of 35

28 Fig. 15: 63-years-old-man with a pain mass in the tibial posterior nerve. Sagittal plane MRI T1w fat-sat Gd+ Enhancement except the tracts and the chystic areas. Page 28 of 35

29 Fig. 16: 63-years-old-man with a pain mass in the tibial posterior nerve. Hypoechogenic lession except the tracts (hyperecogenic) Page 29 of 35

30 Fig. 17: 30-years-old-man with a pain mass in the thenar eminencen (Median nerve). Coronal plane in T1W fat-sat Gd+ heterogeneous enhancement. Page 30 of 35

31 Fig. 18: 30-years-old-man with a pain mass in the thenar eminence (Median nerve). Coronal plane in T1W fat-sat Gd+ Heterogeneous enhancement. Page 31 of 35

32 Conclusion MRI finding can help differentiate the peripheral nerve sheath tumours: 1- The enhancement pattern by echo-doppler: tumoral matrix enhancement suggest neurofibroma and tail enhancement suggest Schwannoma. 2- Heterogeneous appearance and cystic cavitation are much more common in Neurofibromas. 3- The central low intensity focus ("dot") is common in both tumors. 4- Split fat-sign, target sign and the fusiform shape can be seen in the either lession (Neurofibromas and Schwannomas) 5- A painless mass suggest Schwannoma. Pain and growing are degeneration signs. The majority are silent. 6- Neurological deficits (dysesthesia and others) suggest neurofibroma. 7- The superficial lesions are <5cm and the deeper lesions are >5cm. The larger lesions have neurological deficits. Limitations of our study include that the reviewer of the MR images knew that all patients had a pathologically confirmed neurofibroma or Schwannoma. MRI is the technique of choice in the diagnosis of peripheral neurogenic tumours, since it facilitates their characterization and allows for better surgical treatment planning. Images for this section: Page 32 of 35

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34 Fig. 1: 34-years-old-woman with a pain mass in the rigth leg, and recent fast grow. Coronal plane T1W fat-sat Gd+ heterogeneous enhancement Neurofibroma plexiforme with sarcomatose degeneration Fig. 2: 34-years-old-woman with a pain mass in the right leg, and recent fast grow. Axial plane MRI T2W heterogeneous hyperintensity lession in the rigth leg. Page 34 of 35

35 References Imaging of musculoskeletal neurogenic tumors: Radiologic-Pathologic correlation. Mark D. Murphey, W. Sean Smith, Stacy E. Smith, Mark J. Kransdorf, H. Thomas Temple. Archives of AFIP, RSNA ; Neuropathology for the neuroradiologist: Antoni A and Antoni B tissue patterns. F. J. Wippold II, M. Lubner, R. J. Perrin, M. Lämmle, A. Perry. AJNR oct : Extraaxial Neurofibromas Versus Neurilemmomas: Discrimination with MRI.AJR Won-Hee-Jee, Soon-Nam Oh, Thomas McCauley et al. MR imaging of extracranial nerve sheath tumors. JCAT 1992.Varma DG et al. Cross-sectional imaging of peripheral nerve sheath tumors characteristic signs on CT, MR imaging and sonography. AJR 2001; 176: MR f benign peripheral nerve sheath tumors. JCAT 1991; 15: Cerofolini E,Landi A, DeSantis G, Maiorana A, et al. Pictorial review inaging of peripheral nerve tumors Clin Radiol 1997; 52:8-17. Beggs I. Spinal and paraspinal neurofibromatosis: surface coil MR imaging at 1,5 T. Radiology 1987; 162: Peripheral Schwannoma lacking enhancement on MRI. Jonathon A. lee and Carol a. Boles. AJR ; Differentiation between Schwannomas and Neurofibromas in the Extremities and superficial body. Wan Chen Tsai, MD, Hong-Jen Chiou MD, Yi-Hong Chou MD, HoinKai Wang, MD, See-Ying Chion MD, and Cheng-Yen Chang MD. Journal of Ultrasound in Medicine ; Personal Information Page 35 of 35