87 Pathologic Fracture

Pathologic Fracture

Hema N. Choudur, Anthony G. Ryan, and Peter L. Munk

Clinical Presentation

A woman with a known case of thyroid malignancy presented with acute right humeral pain with no history of trauma. She had tenderness and swelling along the proximal aspect of the arm with an inability to move her arm.

Figure 87A

Figure 87B

Figure 87C

Radiologic Findings

Inversion recovery MRI (Fig. 87A) shows gross cortical dusruption through an oval high signal intensity lesion involving the neck and proximal shaft of the right humerus with secondary joint effusion. There is moderate medial displacement of the distal tibial fragment. Fluoroscopy (Fig. 87B) at the time of biopsy demonstrated a fracture of the surgical neck with a lucent lesion in the adjoining bone. The angiogram (Fig. 87C) revealed a dense hypervascular “blush” at the site of the fracture.

Diagnosis

Pathologic fracture, secondary to metastasis.

Differential Diagnosis

Traumatic fracture
Stress fracture

Discussion

Etiology

Bone that is weakened by a preexisting condition, either primarily in the bone or secondary to a metastasis or primary tumor, can result in a fracture with trivial trauma. Usually the diagnosis is straightforward, given a history of malignancy or metabolic disease, but in other cases it may be the first indication of a malignancy. The histology and a directed search often lead to the primary malignancy.

Pathophysiology

There are numerous conditions that weaken the bone, making it susceptible to fracture. These conditions can be classified as generalized disorders causing osteopenia and focal bony lesions.

Generalized disorders (e.g., osteogenesis imperfecta and rickets in children)
Multiple myeloma, osteoporosis, carcinomatosis, and Paget’s disease in the elderly
Benign lesions that weaken bone (e.g., cysts and enchondromas)
Osteomalacia, osteosclerosis, and hyperparathyroidism in adults