A previously healthy 77-year-old man presented with a painful mass in the calf for two months. He had a history of blunt trauma 5 years ago and the injury had been treated conservatively. Physical examination showed a local tenderness and a fusiform, fluctuating mass measuring 15×6×6 cm in the anterolateral aspect of the right calf. The ankle showed a full range of motion with sensory and motor functions preserved. The results of laboratory tests, including glucose, alkaline phosphatase, calcium, phosphate and erythrocyte sedimentation rate were all normal. Plain X-ray and MRI of the calf were abnormal (Figures 1, 2).
Figure 1.
Anteroposterior (A) and lateral (B) radiographs of the cruris.
Figure 2a.
Frontal spin-echo T1-weighted MRI of the calf.
What are the abnormalities seen in the plain radiographs and MRI?
What’s your differential diagnosis?
What’s the diagnosis?
Answer on page 55.
Figure 2b.
Axial T1- and T2-weighted MRI scan (proximal section) (left).
Figure 2c.
Axial T1- and T2-weighted MRI scans (distal section) (right).