A 59-year-old woman presents with a longstanding painful swelling on the dorsal side of the right wrist. No symptoms in other joints. No history of trauma, infection, or tumor.
Examination findings
A rough, non-displaceable resistance at the dorsal carpal region is palpable. Extension is severely limited, making a fist is only partially possible, all laboratory values are within the normal range.
The x-ray shows several ossicles on the dorsal side of the wrist, some of which are synostosed with the carpals on CT. In addition, cystic inclusions with marginal sclerosis are seen in the carpals and in the ulnar head.
What would you suspect, and what further examination would you recommend?
Contrast-enhanced MRI shows cartilaginous tissue originating from the carpals and surrounding the ossifications. The signal intensity of the extraosseous tumor part is identical to that of the cystic, intraosseous inclusions.
Diagnosis: hemimelic epiphyseal dysplasia (Trevor's disease, Fairbank's disease)
The finding is confirmed in the pathohistology; a radical removal of tissue is not performed.
Background information
Trevor's disease is a very rare skeletal dysplasia characterized by localized proliferation of osteochondral tissue. It usually first manifests during childhood or adolescence. Osteochondral tissue originates in one or more epiphyses. Accessory osseous and cap-like cartilage tissue are connected to the epiphyses of neighboring bones.
Approximately 300 cases of Trevor disease have been described in literature. Unilateral manifestation in one half of the body is characteristic – hence the term “hemimelic”. Most commonly, the dysplasia is localized at the ankle or talus and at the knee. Three degrees of severity are distinguished: localized, voluminous and generalized. Presentations of Trevor's disease in the hand have only been described in 10 patients, with one report coming from our own research group (Gölles et al., Eur J Radiol 2011;77:245).
Learning points
The combination of bony accessoria and cystic, marginally sclerosed inclusions in several neighboring bone should prompt consideration of osteochondral proliferative tissue. Cartilage tissue can be detected on MRI based on the signal intensity in T2*-weighted gradient echo sequences and on peripheral contrast enhancement.
