A 29-year-old male patient presented with progressive deformity of his left elbow since childhood. He was constantly treated with factor VIII for severe hemophilia A. He stated that he had no other diseases and had been submitted to any surgeries. At physical examination, he presented with restricted elbow extension (Figure 1A) and had a similar deformity of the right elbow.

Figure 1.

(A) Physical examination of the elbow demonstrating limited joint extension and deformity. (B) Radiography with notable bone deformity, in particular the distal humerus. (C) Ultrasonography demonstrating heterogeneous, ill defined, oval deformity with adjacent bone irregularity without vascularization according to a Doppler study. (D) Contrast T1 FAT SAT MRI with subtraction shows morphostructural deformity of elbow joint, with extensive deposition of low signal material in the synovium (hemosiderin) and extra-osseous hemophiliac pseudotumor measuring 4.9×3.5×3.6cm (gray arrow).

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The patient is negative for anti-factor VIII inhibitor. A radiograph demonstrated clear deformity of the distal humerus with lytic lesions and edema of the surrounding soft tissues (Figure 1B). Ultrasonography identified a heterogeneous, ill-defined, oval image with an adjacent bone irregularity without vascularization by Doppler ultrasonography (Figure 1C). Magnetic resonance imaging (MRI) demonstrated morphostructural deformity of elbow joint, with extensive deposition of low signal material in the synovium and extra-osseous hemophiliac pseudotumor (Figure 1D).

A hemophilic pseudotumor is the result of repeated episodes of bleeding at a bone fracture site or as a result of sub-periosteal hemorrhage or bleeding into soft tissue due to absence or lack of effective replacement treatment.1–3