Painful Benign Bone Tumors of the Hip: A Pictorial Review

Purpose or Learning Objective: To understand the role of imaging in the diagnostics and treatment of painful benign bone tumors occurring in the proximity of the hip joint.

Methods or Background: The bones forming the hip joint, especially the proximal femur, are a common location of benign bone tumors. Approximately 20% of osteoid osteomas and 11% of osteoblastomas occur in the proximal femur. Other benign lesions occurring near the hip joint are solitary bone cyst, aneurysmal bone cyst (ABC), fibrous dysplasia, and cartilaginous tumors (e.g., exostosis, enchondroma, or chondroblastoma). Symptoms of these tumors are initially often nonspecific, which may cause a diagnostic delay. Pain is typically a presenting symptom in osteoid osteomas, osteoblastomas, ABCs, and some chondroblastomas. Pain associated with solitary bone cyst and fibrous dysplasia raises suspicion of a pathologic fracture. In exostosis, pain is usually due to a conflict with nearby structures; however, the lesion should always be assessed for a possible malignant transformation.

Results or Findings: Plain films are an initial imaging test in the case of a painful hip, sometimes coupled with ultrasonography. Small lesions, especially osteoid osteomas, may not be visible on radiography. Secondary radiographic signs include periarticular osteopenia and widening of the joint space due to effusion and may mimic infection/inflammation.

Computed tomography (CT) is the best method to evaluate bone structure and an optimal test for the depiction of the nidus in patients suspected of osteoid osteoma. CT is also superior to plain films in demonstrating pathologic fracture lines in osteolytic lesions. Magnetic resonance imaging (MRI) is especially useful in characterizing the tumor matrix, depicting the cartilage cap in osteochondromas, and showing the features of soft tissue impingement.

In recent years, CT- and MRI-guided minimally invasive percutaneous procedures have been increasingly used in treating benign bone tumors as an alternative to open surgery. Benefits of minimally invasive techniques include precise destruction of tumor tissue, a shorter hospital stay as compared with resective surgery, and a low rate of complications.

Conclusion: Benign bone tumors should be considered in the differential diagnosis of persistent hip pain. A well-designed imaging algorithm allows for a proper and timely diagnosis. In selected tumors, minimally invasive therapeutic procedures can be used successfully instead of open surgery.

Publication History

Article published online:
22 May 2024