Synovial Hemangioma of the Knee

44 y/o Female with intermittent knee pain and swelling for several years • Xray of the Week

Figure 1.a. T1 weighted sagittal image demonstrating a low signal intensity lobulated intra-articular mass.

Figure 1.b. FSE PD weighted sagittal image with fat saturation demonstrating the markedly hyper-intense mass with characteristic low-signal-intensity linear structures, due to fibrous septa.

Figure 2. Axial FSE PD weighted image with fat saturation demonstrating the markedly hyper-intense mass with characteristic low-signal-intensity linear structures, due to fibrous septa.

Discussion:

Synovial haemangiomas are rare benign vascular malformations that occur in synovial joints. They may be a form of soft tissue hemangioma and occasionally synovial haemangiomas may present with a hemarthrosis. However, symptoms are usually non-specific, consisting of pain, swelling and limited range of motion of the affected joint. Most synovial haemangiomas are seen in the knee.

Phleboliths seen on plain radiographs may be diagnostic if present.

As in this case, MRI typically shows a lobulated intra-articular mass which is usually low or intermediate signal intensity on T1 weighted images and markedly hyper-intense on T2 weighted images. In addition, the T2 weighted images characteristically demonstrate low-signal-intensity linear structures in the mass, due to fibrous septa or vascular channels.

Since MRI demonstrates the precise location and extent of the tumor, it is essential for preoperative planning. Pedunculated and well-circumscribed lesions usually are resected arthroscopically. Diffuse hemangiomas require open wide excision and recurrence is common in cases of diffuse lesions.

References:

1. Arslan H, Islamoglu N, Akdemir Z, et al. Synovial Hemangioma in the Knee: MRI Findings. J Clin Imaging Sci. 2015; 5: 23. Published online 2015 Apr 30.

2. Barakat MJ, Hirehal K, Hopkins JR et-al. Synovial hemangioma of the knee. J Knee Surg. 2007;20 (4): 296-8.

3. Sheldon PJ, Forrester DM, Learch TJ. Imaging of intraarticular masses. Radiographics. 25 (1): 105-19

4. Watanabe S, Takahashi T, Fujibuchi T et-al. Synovial hemangioma of the knee joint in a 3-year-old girl. 2010. Journal of Pediatric Orthopaedics B. 19(6):515-520, NOV 2010.

5. Rajni, Khanna G, Gupta A, Gupta V. Synovial hemangioma: A rare benign synovial lesion. Indian J Pathol Microbiol [serial online] 2008 [cited 2018 Feb 11];51:257-8. Available from: http://www.ijpmonline.org/text.asp?2008/51/2/257/41676

Phillip Tirman, MD is the Medical Director of Musculoskeletal Imaging at the Renaissance Imaging Center in Westlake Village, California. A nationally recognized expert in the applications of MRI for evaluating MSK and spine disorders, Dr. Tirman is the co-author of three textbooks, including MRI of the Shoulder and Diagnostic Imaging: Orthopedics. He is also the author or co-author on over sixty original scientific articles published in the radiology and orthopedic literature.

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Kevin Rice, MD is the president of Global Radiology CME

Dr. Rice serves as the Chair of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field.

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