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Age / Sex : 23 / F
Age / Sex : 23/F
Chief complaint : Right knee pain (D:16 years)
1) What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of
this case.
* Send Application Answers to In Sook Lee, MD ([email protected])
Courtesy : Ji Young Hwang, Ewha Womans University School of Medicine Mokdong
Hospital)
Diagnosis: (Synovial) hemangioma
Discussion
Findings:
X-ray (Knee
AP and lateral view)
increased
radiopacity of infrapatellar fat with circular soft tissue calcification
(phlebolith)at posterolateral aspect of knee
MRI
Mass is
poorly marginated and isointense relative to skeletal muscle on T1-weighted MR
image.The mass contains coarse strands or bands of fat (high signal intensity
on T1-weighted image). On T2-weighted MR image, heterogeneously hyperintense
signal intensity with foci of intermediate to low signal intensity
(hemosiderin) and low signal intensity (phlebolith) is evident.
The mass is
located in infrapatellar fat pad and deep extramuscular space between
iliotibial band and lateral femoral epicondyle of knee joint.
Differential Diagnosis: Synovial hemangioma
R/O Pigmented
villonodular synovitis (PVNS)
R/O giant cell tumor
Diagnosis:
synovial hemangioma of knee
Discussion:
Hemangioma is the most frequent soft
tissue tumor of childhood. The classification of hemangioma is based on the
type of vascular channel that dominates histologic appearance.
Capillary hemangioma appears early
in life in the skin and subcutaneous tissue and composed solely of capillaries.
If histologic appearance shows widely dilated capillaries, the tumor is called
a cavernous hemangioma. Cavernous hemangioma commonly calcify (phleboliths) and
is located in deep tissue without spontaneous involution. Venous hemangioma
contains thicker wall and smooth muscle cell, and located in deep muscle,
extramuscle of extremity and retroperitoneum.
Hemangioma may involve muscle,
extramuscular soft tissue, synovium, and bone. Synovial hemangioma is commonly
encountered in the knee joint.
Radiologic findings of hemangioma
are soft tissue mass containing nonvascular tissue such as fat, fibrous tissue,
myxoid stroma, smooth muscle, hemosiderin, thrombus, phlebolith and any
vascular tissue. Phleboliths in the joint and soft tissue are useful radiologic
finding in diagnosis of hemangioma. Hemosiderin deposition in the synovial
membrane simulates that seen in pigmented villonodular synovitis and
hemophilia.
Hemangioma is poorly marginated and
isointense relative to skeletal muscle and contains coarse strands or bands of
fat (high signal intensity) on T1-weighted MR image. On T2-weighted MR image,
heterogeneously hyperintense signal intensity with foci of low signal intensity
(phlebolith) is evident.
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