Hemophilic pseudotumor of the knee joint: Emphasizing prevention and early diagnosis in a rare disease

Abstract

Key clinical message: Hemophilic pseudotumors are rare complications occurring in individuals with severe hemophilia, characterized by progressive cystic swellings in muscles and/or bones due to recurrent bleeding. Timely initiation of factor VIII replacement is crucial.

Abstract: Hemophilic pseudotumors are rare complications occurring in individuals with severe hemophilia, characterized by progressive cystic swellings in muscles and/or bones due to recurrent bleeding. Although their incidence has decreased with the advent of factor VIII replacement therapy, they still create challenges, particularly in regions with limited access to medical care. Here, we present a case report of a hemophilic pseudotumor of the knee joint in a 15-year-old male with hemophilia A. The patient presented with severe left knee pain, swelling, and restricted range of motion, prompting further investigation. Imaging studies revealed lytic lesions, and MRI bone signal changes consistent with hemophilic pseudotumors. Prompt initiation of factor VIII replacement therapy and supportive management led to a significant improvement in symptoms and joint functionality. Follow-up after 2 months showed that the swelling had significantly reduced in size, with marked improvement in the functionality of the knee joint. This case confirms what is already known in the hemophilia literature: how important it is to prevent, diagnose, and treat pseudotumors early in hemophilia. However, longer clinical and imaging follow-up of this case is necessary to determine whether the complaints associated with pseudotumors resolve with hematologic treatment or will require surgical treatment.

Keywords: hemophilia; hemophilic pseudotumor; knee joint; lytic bone lesion; multimodality imaging.

FIGURE 1

Clinical image of the patient showing diffuse swelling of the left knee joint (white circle) and normal right knee joint.

FIGURE 2

Knee radiograph showing lytic area in intercondylar eminence and along lateral tibial plateau (dotted black circle). Distension in supapatellar region with fat pad separation suggesting suprapatellar bursal fluid (white arrows).

FIGURE 3

Coronal reconstructed (A, B) and axial (C) non contrast CT images of knee joint showing lytic lesions in tibial plateau (dotted circles) and widened intercondylar notch (block arrows).

FIGURE 4

T1W (A, B) and PD (C, D) sagittal MRI images showing suprapatellar T1/PD hyperintense effusion (block white arrows) in patellofemoral compartment extending to suprapatellar recess suggesting hemorrhagic effusion. T1 and PD heterogeneously hyperintense lesions (dotted white arrows) in tibial plateau and medial femoral epicondyle suggesting hemorrhagic contents‐hemophilic pseudotumor.

FIGURE 5

Axial [T1W] (A), [PD] (B) and Coronal [T1W] (C), [PD] (D) images showing widened intercondylar notch (bent white arrows) with heterogeneously hyperintense lesions in tibial plateau (dotted white circle) and hypointense synovial thickening (straight white arrows).