Catry, F

Vanhoenacker, Filip

Vansevenant, Milan

English

M Vansevenant

F M Vanhoenacker

F Catry

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Vansevenant, M et al 2015 Tophaceous Gout of the Extensor Mechanism of 
the Knee. Journal of the Belgian Society of Radiology, 99(1), pp. 93–94, DOI: 
http://dx.doi.org/10.5334/jbr-btr.861
A 51-year-old male presented at our department with a 
slightly painful soft tissue lump at the superior pole of 
the patella and limited range of joint motion. MRI of the 
left knee confirmed a soft tissue mass within the distal 
quadriceps extending into the superior aspect of the 
patella. The mass was hypointense on T1-weighted images 
(WI) (Fig. A, arrows) and slightly heterogeneous hyperin-
tense on fat saturated intermediate-WI (Fig. B, arrows). A 
bone infarct was seen in the distal femur (Fig. A and B, 
arrowhead). After administration of gadolinium contrast 
heterogeneous enhancement was seen. Gradient-echo 
sequences did not reveal blooming artifact. Addition-
ally Cone Beam CT showed the soft tissue mass as being 
slightly hyperdense to the surrounding soft tissue (Fig. C, 
arrow). Partially sclerotic delineated osteolysis  was seen at 
the patella (Fig. C, arrowhead).
Based on the clinical presentation and imaging findings, 
tophaceous gout was suspected. After repeated anamne-
sis, the patient admitted alcohol overconsumption for 
many years and having previous gout attacks at the feet. 
Because of the aggressive nature of the process, a biopsy 
was performed in order to exclude a malignant tumor. The 
biopsy specimen showed the presence of monosodium 
urate (MSU) crystals, in keeping with tophaceous gout. 
The patient was reassured, was provided with appropriate 
dietary advice and nonsteroidal anti-inflammatory drugs.
Comment
Gout is a metabolic disorder resulting in hyperuricemia. It 
is a very common condition with a peak incidence at the 
fifth decade of life. Men are more affected than women. 
Clinical manifestations of gout are asymmetric arthritis 
and/or soft tissue nodules. The most affected site is the 
first metatarsophalangeal joint, followed by the first inter-
phalangeal joint. The hand and wrist are also commonly 
affected. The patella is an unusual site of gout. Clinical 
presentation and laboratory values are usually sufficient 
IMAGES IN CLINICAL RADIOLOGY
Tophaceous Gout of the Extensor Mechanism 
of the Knee
M. Vansevenant*,†, F. M. Vanhoenacker*,†,‡ and F. Catry*
* Department of Radiology, AZ Sint Maarten, Mechelen-Duffel, 
Belgium
† Department of Radiology, Ghent University Hospital (UZ Gent), 
Belgium
‡ Department of Radiology, Antwerp University Hospital (UZA), 
Belgium
Corresponding author: M. Vansevenant Figures A–C:
Vansevenant et al: Tophaceous Gout of the Extensor Mechanism of the Knee94
for diagnosis. The gold standard remains the demonstra-
tion of MSU crystals in the joint fluid or in the tophi.
The first stage in gout is an asymptomatic hyperurice-
mia without imaging abnormalities. After several years of 
hyperuricemia, a first attack of gouty arthritis can occur. 
This is usually monoarticular and radiographic evaluation 
remains normal. Sometimes only soft tissue swelling and 
joint effusion can be seen. Tophi and erosions occur usu-
ally more than 10 years after the first attack. This time is 
needed to store the MSU crystals in soft tissues.
Radiographic manifestations of chronic gout are well-
defined punched-out erosions with overhanging edges, 
late preservation of the joint space, lack of periarticular 
bone demineralization, soft tissue nodules of high density, 
asymmetric involvement and intraosseous calcifications. 
Tophaceous gout is a term, designating the presence of 
MSU crystals within the soft tissues. Although relatively 
dense on plain films, soft tissue calcifications are very 
rare, unless there is decreased renal clearing of calcium 
in patients with renal insufficiency. Computed tomo-
graphy (CT) and Magnetic Resonance Imaging (MRI) are 
usually not needed to diagnose gout and are nonspecific. 
On CT, tophi are slightly hyperdense compared to soft 
tissue. CT is more sensitive than plain films to detect 
subtle soft tissue calcifications even in the absence of 
renal insufficiency. Some authors recommend dual source 
CT for characterization of gout tophi. On MRI, tophi are 
 hypointense on T1-WI and vary from hypointense to 
hyperintense on T2-WI. Heterogeneity on T2-WI may be 
seen, caused by urate crystals or calcium deposition. The 
pattern of enhancement is variable.
In most scenarios, gout is a straightforward diagnosis 
but can mimic infection (acute arthritis) or bone or soft 
tissue neoplasms if located at unusual sites, such as the 
quadriceps tendon and patella. The thought of it in the 
appropriate clinical setting enables the correct diagnosis. 
Additional clues are the knowledge of a history of gout 
at other joints, hyperuricemia, bone infarcts and alcohol 
abuse.
Competing Interests
The authors declare that they have no competing interests.
Reference
 1. Gentili, A. The advanced imaging of gouty tophi. 
Curr Rheumatol Rep. 2006; 8: 231–235. DOI: 
http://dx.doi.org/10.1007/s11926-996-0030-6. PMid: 
16901082.
How to cite this article: Vansevenant, M, Vanhoenacker, F M and Catry, F 2015 Tophaceous Gout of the Extensor Mechanism of 
the Knee. Journal of the Belgian Society of Radiology, 99(1), pp. 93–94, DOI: http://dx.doi.org/10.5334/jbr-btr.861
Published: 15 September 2015
Copyright: © 2015 The Author(s). This is an open-access article distributed under the terms of the Creative Commons 
Attribution 3.0 Unported License (CC-BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, 
provided the original author and source are credited. See http://creativecommons.org/licenses/by/3.0/.
 
                          OPEN ACCESS Journal of the Belgian Society of Radiology is a peer-reviewed open access journal published by Ubiquity Press.


Journal of the Belgian Society of Radiology

Tophaceous gout of the extensor mechanism of the knee

Ghent University Academic Bibliography

Vansevenant, M et al 2015 Tophaceous Gout of the Extensor Mechanism of the Knee. Journal of the Belgian Society of Radiology, 99(1), pp. 93–94, DOI: http://dx.doi.org/10.5334/jbr-btr.861A 51-year-old male presented at our department with a slightly painful soft tissue lump at the superior pole of the patella and limited range of joint motion. MRI of the left knee confirmed a soft tissue mass within the distal quadriceps extending into the superior aspect of the patella. The mass was hypointense on T1-weighted images (WI) (Fig. A, arrows) and slightly heterogeneous hyperin-tense on fat saturated intermediate-WI (Fig. B, arrows). A bone infarct was seen in the distal femur (Fig. A and B, arrowhead). After administration of gadolinium contrast heterogeneous enhancement was seen. Gradient-echo sequences did not reveal blooming artifact. Addition-ally Cone Beam CT showed the soft tissue mass as being slightly hyperdense to the surrounding soft tissue (Fig. C, arrow). Partially sclerotic delineated osteolysis  was seen at the patella (Fig. C, arrowhead).Based on the clinical presentation and imaging findings, tophaceous gout was suspected. After repeated anamne-sis, the patient admitted alcohol overconsumption for many years and having previous gout attacks at the feet. Because of the aggressive nature of the process, a biopsy was performed in order to exclude a malignant tumor. The biopsy specimen showed the presence of monosodium urate (MSU) crystals, in keeping with tophaceous gout. The patient was reassured, was provided with appropriate dietary advice and nonsteroidal anti-inflammatory drugs.CommentGout is a metabolic disorder resulting in hyperuricemia. It is a very common condition with a peak incidence at the fifth decade of life. Men are more affected than women. Clinical manifestations of gout are asymmetric arthritis and/or soft tissue nodules. The most affected site is the first metatarsophalangeal joint, followed by the first inter-phalangeal joint. The hand and wrist are also commonly affected. The patella is an unusual site of gout. Clinical presentation and laboratory values are usually sufficient IMAGES IN CLINICAL RADIOLOGYTophaceous Gout of the Extensor Mechanism of the KneeM. Vansevenant*,†, F. M. Vanhoenacker*,†,‡ and F. Catry** Department of Radiology, AZ Sint Maarten, Mechelen-Duffel, Belgium† Department of Radiology, Ghent University Hospital (UZ Gent), Belgium‡ Department of Radiology, Antwerp University Hospital (UZA), BelgiumCorresponding author: M. Vansevenant Figures A–C:Vansevenant et al: Tophaceous Gout of the Extensor Mechanism of the Knee94for diagnosis. The gold standard remains the demonstra-tion of MSU crystals in the joint fluid or in the tophi.The first stage in gout is an asymptomatic hyperurice-mia without imaging abnormalities. After several years of hyperuricemia, a first attack of gouty arthritis can occur. This is usually monoarticular and radiographic evaluation remains normal. Sometimes only soft tissue swelling and joint effusion can be seen. Tophi and erosions occur usu-ally more than 10 years after the first attack. This time is needed to store the MSU crystals in soft tissues.Radiographic manifestations of chronic gout are well-defined punched-out erosions with overhanging edges, late preservation of the joint space, lack of periarticular bone demineralization, soft tissue nodules of high density, asymmetric involvement and intraosseous calcifications. Tophaceous gout is a term, designating the presence of MSU crystals within the soft tissues. Although relatively dense on plain films, soft tissue calcifications are very rare, unless there is decreased renal clearing of calcium in patients with renal insufficiency. Computed tomo-graphy (CT) and Magnetic Resonance Imaging (MRI) are usually not needed to diagnose gout and are nonspecific. On CT, tophi are slightly hyperdense compared to soft tissue. CT is more sensitive than plain films to detect subtle soft tissue calcifications even in the absence of renal insufficiency. Some authors recommend dual source CT for characterization of gout tophi. On MRI, tophi are  hypointense on T1-WI and vary from hypointense to hyperintense on T2-WI. Heterogeneity on T2-WI may be seen, caused by urate crystals or calcium deposition. The pattern of enhancement is variable.In most scenarios, gout is a straightforward diagnosis but can mimic infection (acute arthritis) or bone or soft tissue neoplasms if located at unusual sites, such as the quadriceps tendon and patella. The thought of it in the appropriate clinical setting enables the correct diagnosis. Additional clues are the knowledge of a history of gout at other joints, hyperuricemia, bone infarcts and alcohol abuse.Competing InterestsThe authors declare that they have no competing interests.Reference 1. Gentili, A. The advanced imaging of gouty tophi. Curr Rheumatol Rep. 2006; 8: 231–235. DOI: http://dx.doi.org/10.1007/s11926-996-0030-6. PMid: 16901082.How to cite this article: Vansevenant, M, Vanhoenacker, F M and Catry, F 2015 Tophaceous Gout of the Extensor Mechanism of the Knee. Journal of the Belgian Society of Radiology, 99(1), pp. 93–94, DOI: http://dx.doi.org/10.5334/jbr-btr.861Published: 15 September 2015Copyright: © 2015 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 Unported License (CC-BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. See http://creativecommons.org/licenses/by/3.0/.                           OPEN ACCESS Journal of the Belgian Society of Radiology is a peer-reviewed open access journal published by Ubiquity Press.

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Tophaceous gout of the extensor mechanism of the knee

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