Post-traumatic osteoid osteoma in an 18-year-old adolescent

Abstract

Osteoid osteoma (OO) is a painful, benign bone-forming lesion, which often poses a diagnostic challenge. The aetiology of OO is still poorly understood. Although not generally accepted, an association with previous trauma or infection has occasionally been suggested. We present a case of an OO 12 years following an ulnar fracture. Radiologists should consider OO as a potential delayed "complication" of a previous fracture. Persistent pain at a previous fracture site should alert the clinician to request cross-sectional imaging. CT scanning plays a pivotal role in the correct diagnosis of OO.

Figure 1.

(a) Initial radiograph (posteroanterior film) 12 years previously shows an oblique fracture at the mid-diaphysis of both radius and ulna. (b) Postoperative anteroposterior film depicting intramedullary pinning and beginning signs of callus formation. The radius demonstrates nearly complete bony bridging. The ulna shows partial but incomplete bony bridging.

Figure 2.

Anteroposterior (a) and lateral (b) plain radiographs at current admission reveal a focal intracortical lucency (white arrow) adjacent to the previous fracture site with surrounding sclerosis and cortical thickening (white arrowheads).

Figure 3.

(a) Coronal T₁ weighted image. (b) Coronal T₂ weighted image. (c) Axial T₂ weighted image. (d) Axial fat-suppressed T₁ weighted image after administration of gadolinium contrast. (e) Axial subtraction of the images before and after gadolinium contrast administration. MRI shows a focal intracortical lesion in the ulna with low central signal intensity and mineralization on both T₁ and T₂ weighted images (white arrows). After administration of gadolinium contrast, there is marked peripheral enhancement of the lesion with perilesional bone marrow and soft-tissue oedema (white arrowheads).

Figure 4.

(a) Axial CT image. (b) Coronal reformatted CT image. CT visualization of a cortical nidus in the ulna, suggestive of an osteoid osteoma.