Fatty masses: results of MRI and CT evaluations

Fatty masses: results of MRI and CT evaluations Poster No.: C-2324 Congress: ECR 2018 Type: Scientific Exhibit Authors: M. E. Scherer, J. Cardenas Marquez, E. Rossetto, A. 1 2 1 1 1 1 Calderwood, F. M. Olivera Plata, P. Schvartzman, C. R. 1 1 2 DERAGOPYAN ; CABA, C.A.B.A/AR, Buenos Aires/AR Keywords: Oncology, Musculoskeletal system, Musculoskeletal soft tissue, MR, CT-High Resolution, Comparative studies, Education, Perception image, Cancer, Education and training, Neoplasia DOI: 10.1594/ecr2018/C-2324 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. www.myesr.org Page 1 of 14

Aims and objectives To illustrate multiple lipomatous masses using MRI and CT imaging modalities, pointing out the meaning of the nonlipomatous components in order to differentiate between lipoma and adipocytic tumors. To determine the significant findings in patients with lipomatous tumors and help to clarify the best features to indicate prognosis in cases with adverse clinical behavior. Methods and materials The authors review the radiological spectrum of fat-containing tissue masses, with emphasis on computed tomography, magnetic resonance imaging with pathologic correlation and monitoring of clinical behavior. We retrospectively examined a database of CT and MRI examinations of performed studies in our institution over a period of 4 years. In these review, 78 patients with lipomatous masses where found. CT and MRI interpretations with their corresponding pathology reports were correlated. We use the World Health Organization (WHO) classification for the soft tissue tumors (2013), which divides lipomatous tumors into benign, intermediate (locally aggressive) and malignant (table 1). The MRI protocol included T1-weighted, T2-weighted, fat-suppressed/fluid-sensitive sequences and T1-weighted images after injection of contrast agent (Gadolinium) with and without fat suppression. The images were assessed for the number, site, size and margin of the lesions, as well as the signal intensity, the internal architecture, the effect on the surrounding tissue (edema, neurovascular involvement) and the enhancement pattern. When a fat-containing tissue mass does not satisfy the radiologic critera for lipoma, there is a wide range of differential diagnosis, including histological subtypes. Images for this section: Page 2 of 14

Table 1: World Health Organization (WHO) classification of soft tissue tumors. - CABA/AR Page 3 of 14

Results Conventional lipomas may contain a few thin septa. Nevertheless, they are homogeneously fatty masses (fig. 1). Bands of muscle fibers are also acceptable components of intramuscular lipomas. Thickened or nodular septa (generally > 3 mm), associated nonadipose masses, prominent foci of high T2 signal, and prominent areas of enhancement are all associated with increased risk of well-differentiated liposarcoma (fig. 2). A well-differentiated liposarcoma produces an image of a predominantly fatty mass with irregularly thickened linear or nodular septa, which decreases signal intensity on T1-WI and increases signal intensity on T2-WI. The myxoid, round and pleomorphic subtypes do not contain substantial amounts of fat. A dedifferentiated type is best defined as a bimorphic neoplasm in which a borderline or low-grade malignant neoplasm is juxtaposed with a highgrade sarcoma (fig. 3). The subtypes of liposarcomas with greater nonlipomatous components on imaging studies tend to show less differentiation and are usually more aggressive histologically and clinically. The features to correlate radiological and microscopic findings are the size (exceeding 30 mm), presence of thick or nodular septa, areas with high T2 and low T1 signal intensity, contrast enhancement, a partially ill-defined margin, neurovascular involvement, calcifications, hemorrhage and muscular fibers. The most statistically significant predictor of liposarcoma was thick irregular septa and nonfatty elements. Lipomas typically have a characteristic MR imaging appearance that is independent of location (image 5). Images for this section: Page 4 of 14

Fig. 1: A) and B) Axial and coronal T1-WI, C) and D) Coronal fat-saturated T1-WI and STIR-WI. Deep and voluminous mass on right leg showing homogeneous fat-containing components. The mass is inside the rectus femoris muscle. Note the presence of thin septa and capsule without nodularity or any nonadipose component. Page 5 of 14

Fig. 2: A) and C) Coronal and axial T1. B) and D) Axial T1 FS-WI with gadolinium. E) Sagital T1 FS-WI. Showing a mass in the right tigh hyperintense in T1, suppressed with Fat Sat pulses, with multiple bright septa after the administration of paramagnetic contrast. WELL-DIFFERENCIATED OR ATIPICAL LIPOSARCOMA Page 6 of 14

Fig. 3: A) and B) Coronal and axial T1. C) and D) Coronal and axial T1 FS-WI. Hyperintense mass lobed appearance,is displacing the vastus lateralis muscle in the distal region of the right tigh Continue on image 4. Page 7 of 14

Fig. 4: A) Sagital STIR, B) and C) Coronal T1 FS with gadolinium on the same patient of image 3. Hypointense signal with brighter septa after the administration of paramagnetic contrast. Well-Differenciated Liposarcoma. Page 8 of 14

Fig. 5: Coronal (a), Sagital (b) and axial (c) T2 and T2FS (d), demonstrating a mass in the left inguinal canal. A hernia sac with fatty content is observed, located in the left inguinal canal. Hyperintense in T2 and hypointense in FS sequences. INGUINAL CANAL LIPOMA Page 9 of 14

Fig. 6: CTAxial and Coronal reconstruction Chest X-Ray Front View. Small intrathoracic extrapulmonary Lipoma, on the periphery of the left lung. Page 10 of 14

Fig. 7: A), B) and D) Coronal, axial and Sagital T1. Small mass hyperintense, in the proximal region of the right arm C) and E) Sagital and axial T1 FS with gadolinium shows avid enhacement. DE-DIFFERENTIED LIPOSARCOMA on biopsy. Page 11 of 14

Fig. 8: Both Axial and Coronal of Abdominal TC and MRI showing well delimited mass, with macroscopic fat component, dependant of the inferior pole of the right kidney. Minimal extension to the renal sinus is demonstrated. Huge Renal Angiomyolipoma (AML) Page 12 of 14

Conclusion Regarding the differences in treatment, prognosis, and long term follow-up, it will be of major importance to distinguish conventional lipomas from well-differentiated liposarcomas. Imaging plays an important role in the diagnosis, surveillance, and response assessment of liposarcoma. It will also be significant to remember that if the malignancy of the lession can not be dismissed by imaging techniques, a biopsy should be performed. Personal information References 1. 2. 3. 4. 5. 6. 7. 8. de Salazar, A., Larrañaga, N., Espil, G., Oyarzún, A., & Kozima, S. (2016). Lesiones grasas de la cabeza a los pies. Revista Argentina de Radiología, 80(1), 45-54. https://doi.org/10.1016/j.rard.2015.10.008 Kransdorf, M. J., Moser, R. P., Meis, J. M., & Meyer, C. A. (1991). Fatcontaining soft-tissue masses of the extremities. Radiographics : A Review Publication of the Radiological Society of North America, Inc, 11(1), 81-106. https://doi.org/10.1148/radiographics.11.1.1996399 Gupta, P., Potti, T. A., Wuertzer, S. D., Lenchik, L., & Pacholke, D. A. (2016). Spectrum of Fat-containing Soft-Tissue Masses at MR Imaging: The Common, the Uncommon, the Characteristic, and the Sometimes Confusing. RadioGraphics, 36(3), 753-766. https://doi.org/10.1148/ rg.2016150133 Kodzo-Grey Venyo, A., & Deoleker, M. (2011). Paratesticular liposarcoma of the spermatic cord: a case report and a review of the literature. West African Journal of Medicine, 30(6), 447-452. Retrieved from http://www.rjme.ro/ RJME/resources/files/56031511531157.pdf Tobajas, E. (2017). Not the usual liposarcoma... could it be a fatty benign tumor? Jaovisidha, S., Suvikapakornkul, Y., Woratanarat, P., Subhadrabandhu, T., Nartthanarung, A., & Siriwongpairat, P. (2010). MR imaging of fat-containing tumours: The distinction between lipoma and liposarcoma. Singapore Medical Journal, 51(5), 418-423. Liposarcomas, W., Gaskin, C. M., & Helms, C. A. (2004). Lipomas, Lipoma Variants, and Well-Differentiated Liposarcomas (Atypical Lipomas):, (March), 733-739. Ramos-Pascua, L. L. R., Guerra-Álvarez, O. a., Sánchez-Herráez, S., Izquierdo-García, F. M., Maderuelo-Fernández, J. Á., Guerra-Alvarez, S., Page 13 of 14

Maderuelo-Fernández, J. Á. (2013). Lipomas intramusculares : bultos benignos grandes y profundos. Revisión de una serie de 51 casos. Revista Española de Cirugía Ortopédica Y Traumatología, 57(6), 391-397. https:// doi.org/10.1016/j.recot.2013.09.010 9. Exhibit, E., Tandon, A. A., Lim, M. C., & Chong, B. K. (2012). Soft tissue lipomas, lipoma variants and liposarcomas : MRI evaluation and review of literature. 10. Barile, A., Zugaro, L., Catalucci, A., Caulo, M., Di Cesare, E., Splendiani, A., Masciocchi, C. (2002). Soft tissue liposarcoma: Histological subtypes, MRI and CT findings. Radiologia Medica, 104(3). 11. O'Regan, K. N., Jagannathan, J., Krajewski, K., Zukotynski, K., Souza, F., Wagner, A. J., & Ramaiya, N. (2011). Imaging of liposarcoma: Classification, patterns of tumor recurrence, and response to treatment. American Journal of Roentgenology, 197(1), 37-43. https://doi.org/10.2214/ajr.10.5824 Page 14 of 14