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<v ->Now, there are in fact, three other lesions

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that have signal intensity characteristics

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similar to pigmented villonodular synovitis

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or localized nodular synovitis. These are all rare.

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I'm gonna show you one example of you each.

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The first of these, given to me by a radiologist,

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a previous fellow who was at the Navy hospital

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in San Diego is a collagenous fibroma, also known as

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desmoplastic fibroblastoma. It is considered benign.

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It's a lesion related to proliferation of fibrous tissue.

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Seen in middle aged people, more often in man than a woman,

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and more characteristically localizing, not within a joint

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but within subcutaneous tissue, within muscle, within fascia

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but occasionally occurring within a joint or within a bursa.

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The signal intensity generally dominated by low signal

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and typically not hemosiderin deposition.

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Here's an example that appeared to localize mainly

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within the subacromial or the subdeltoid bursa

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about the glenohumeral joint.

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I cannot remember if there was intra-articular

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extension of this lesion, but clearly you might think

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of a villonodular bursitis in a case like this.

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The second lesion, that can look a bit like PVNS,

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is nodular fasciitis.

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It, too, is a benign fibrous proliferative lesion,

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occurring in a slightly younger age group,

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typically 20 to 40 years of age.

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Once again, more often seen

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within subcutaneous tissue muscle fascia,

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rarely within synovial tissue.

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We happened to come across a case that we published

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with Phillip Kindynis a number of years ago,

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in which this was nodular fasciitis involving

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the glenohumeral joint with focal masses mainly

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of low signal intensity

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without definite hemosiderin deposition.

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The third of the three lesions is an angiofibroma.

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This is a type of lesion that is often

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associated with tuberous sclerosis,

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although it may occur without tuberous sclerosis.

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It's benign, it's a soft tissue of tumor,

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this one more common in women.

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Seen especially in the lower extremity particularly

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about the knee but also in the thigh near joints, okay,

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but rarely within joints.

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Here's an example of one with a lot of low signal intensity

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sent to me by one of our prior clinical fellows.

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You can see this low signal.

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It looks like a lot of hemosiderin deposition

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but this related to an angio fibroma.