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Synovial Hemangioma of Infrapatellar (Hoffa) Fat Pad: Magnetic Resonance Imaging and Ultrasound Features
Synovial Hemangioma of Infrapatellar (Hoffa) Fat Pad: Magnetic Resonance Imaging and Ultrasound Features
T
he infrapatellar fat pad (IFP) also known as Hoffa fat pad, an intracapsular extrasynovial structure readily visualized on magnetic resonance imaging of the knee,1 can be affected by a variety of pathologic conditions (lipoma, hemangioma, synovial chondromatosis, focal villonodular synovitis, ganglion cyst, osteochondroma, and chondrosarcoma).2 Because synovial hemangioma is an extremely rare disease and often shows nonspecific symptoms (pain, swelling, limping, or limitation of motion), diagnosis could be delayed in many cases.3 Ultrasound is acknowledged to be of considerable value in assessing superficial masses around the knee joint.1 We present a 7-year-old female with intermittent right knee pain, previously classified as juvenile idiopathic arthritis monoarticular and treated with corticosteroids. On clinical examination, there was a swelling in correspondence of IFP with no ligament laxity. Knee alignment was normal. Magnetic resonance imaging with contrast revealed a well-defined mass with lobulated margin arising from IFP, which was heterogeneously hyperintense in T2-weighted images with fat suppression but isointense to muscle in T1-weighted images (Figure 1), suggestive of hemangioma or low-flow venous malformation. The mass shows no signs of restriction of diffusion in diffusion weighted whole body imaging with background signal suppression imaging and post-enhanced images show inhomogeneous contrast enhancement (Figure 2). Ultrasound examination also with dynamic maneuvers of compression demonstrated large liquid and vascular areas, findings attributable to synovial hemangioma (Figure 3, A). There is also focal interruption of the medial patellar ligament of about 4 3 mm with subcutaneous herniation of a small portion of swelling described (Figure 3, B). Sometimes synovial hemangiomas can be aggressive and can infiltrate the surrounding soft tissue or bone.4 Hence, early diagnosis and surgical treatment need to be done to avoid damage to articular cartilage. n Valeria Beltrame, MD Giovanna Romanucci, MD Department of Medicine University Hospital of Padua University Radiology
Figure 1. A, Sagittal T2-weighted image with fat suppression: a mass heterogeneously hyperintense with lobulated margin arising from IFP (arrow); B, same mass of A (arrow), but isointense to muscle in axial T1-weighted turbo spin echo image, suggestive of hemangioma or low-flow venous malformation.
J Pediatr 2016;-:---. 0022-3476/$ - see front matter. Copyright ª 2016 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jpeds.2016.01.052
1
THE JOURNAL OF PEDIATRICS
www.jpeds.com
Figure 2. Sagittal T1-weighted post-enhanced image shows inhomogeneous contrast enhancement of the mass described in Figure 1 (arrow).
Francesco Zulian, MD Department of Pediatrics University Hospital of Padua
Roberto Stramare, MD Department of Medicine University Hospital of Padua University Radiology Padova, Italy
References 1. Helpert C, Davies AM, Evans N, Grimer RJ. Differential diagnosis of tumors and tumor-like lesions of the infrapatellar (Hoffa) fat pad: pictorial review with an emphasis on MR imaging. Eur Radiol 2004;14:2337-46.
2
Volume -
Figure 3. A, B, Ultrasound demonstrated, also with dynamic maneuvers of compression B (arrow), large liquid and vascular areas A (arrow), findings attributable to synovial hemangioma. There is also focal interruption of the medial patellar ligament of about 4 3 mm with subcutaneous herniation of a small portion of swelling described.
2. Ghate SD, Deokar BN, Samant AV, Kale SP. Tumor like swellings arising from Hoffa fat pad: a report of three patients. Indian J Orthop 2012;46:364-8. 3. Kim WH, Kim MH, Kim CG, Kim DW. Synovial hemangioma of Hoffa fat pad demonstrated by RBC SPECT/CT. Clin Nucl Med 2014;39:806-7. 4. Tang G, Niitsu M, Ikeda K, Endo H, Itai Y. Fibrous scar in the infrapatellar fat pad after arthroscopy: MR imaging. Radiat Med 2000; 18:1-5.
Beltrame et al
T
he infrapatellar fat pad (IFP) also known as Hoffa fat pad, an intracapsular extrasynovial structure readily visualized on magnetic resonance imaging of the knee,1 can be affected by a variety of pathologic conditions (lipoma, hemangioma, synovial chondromatosis, focal villonodular synovitis, ganglion cyst, osteochondroma, and chondrosarcoma).2 Because synovial hemangioma is an extremely rare disease and often shows nonspecific symptoms (pain, swelling, limping, or limitation of motion), diagnosis could be delayed in many cases.3 Ultrasound is acknowledged to be of considerable value in assessing superficial masses around the knee joint.1 We present a 7-year-old female with intermittent right knee pain, previously classified as juvenile idiopathic arthritis monoarticular and treated with corticosteroids. On clinical examination, there was a swelling in correspondence of IFP with no ligament laxity. Knee alignment was normal. Magnetic resonance imaging with contrast revealed a well-defined mass with lobulated margin arising from IFP, which was heterogeneously hyperintense in T2-weighted images with fat suppression but isointense to muscle in T1-weighted images (Figure 1), suggestive of hemangioma or low-flow venous malformation. The mass shows no signs of restriction of diffusion in diffusion weighted whole body imaging with background signal suppression imaging and post-enhanced images show inhomogeneous contrast enhancement (Figure 2). Ultrasound examination also with dynamic maneuvers of compression demonstrated large liquid and vascular areas, findings attributable to synovial hemangioma (Figure 3, A). There is also focal interruption of the medial patellar ligament of about 4 3 mm with subcutaneous herniation of a small portion of swelling described (Figure 3, B). Sometimes synovial hemangiomas can be aggressive and can infiltrate the surrounding soft tissue or bone.4 Hence, early diagnosis and surgical treatment need to be done to avoid damage to articular cartilage. n Valeria Beltrame, MD Giovanna Romanucci, MD Department of Medicine University Hospital of Padua University Radiology
Figure 1. A, Sagittal T2-weighted image with fat suppression: a mass heterogeneously hyperintense with lobulated margin arising from IFP (arrow); B, same mass of A (arrow), but isointense to muscle in axial T1-weighted turbo spin echo image, suggestive of hemangioma or low-flow venous malformation.
J Pediatr 2016;-:---. 0022-3476/$ - see front matter. Copyright ª 2016 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jpeds.2016.01.052
1
THE JOURNAL OF PEDIATRICS
www.jpeds.com
Figure 2. Sagittal T1-weighted post-enhanced image shows inhomogeneous contrast enhancement of the mass described in Figure 1 (arrow).
Francesco Zulian, MD Department of Pediatrics University Hospital of Padua
Roberto Stramare, MD Department of Medicine University Hospital of Padua University Radiology Padova, Italy
References 1. Helpert C, Davies AM, Evans N, Grimer RJ. Differential diagnosis of tumors and tumor-like lesions of the infrapatellar (Hoffa) fat pad: pictorial review with an emphasis on MR imaging. Eur Radiol 2004;14:2337-46.
2
Volume -
Figure 3. A, B, Ultrasound demonstrated, also with dynamic maneuvers of compression B (arrow), large liquid and vascular areas A (arrow), findings attributable to synovial hemangioma. There is also focal interruption of the medial patellar ligament of about 4 3 mm with subcutaneous herniation of a small portion of swelling described.
2. Ghate SD, Deokar BN, Samant AV, Kale SP. Tumor like swellings arising from Hoffa fat pad: a report of three patients. Indian J Orthop 2012;46:364-8. 3. Kim WH, Kim MH, Kim CG, Kim DW. Synovial hemangioma of Hoffa fat pad demonstrated by RBC SPECT/CT. Clin Nucl Med 2014;39:806-7. 4. Tang G, Niitsu M, Ikeda K, Endo H, Itai Y. Fibrous scar in the infrapatellar fat pad after arthroscopy: MR imaging. Radiat Med 2000; 18:1-5.
Beltrame et al