Brodie's Abscess of the Ankle Presenting as a Tumor: A Summary of Five Cases

Abstract

Introduction: A Brodie's abscess is a form of subacute osteomyelitis that is often considered in the differential diagnosis of other benign and malignant bone lesions. The authors summarize the findings of five cases of Brodie's abscesses in the distal tibia initially thought to be tumors by the referring physicians.

Case report: All five cases were presented to the referring physicians with a chief complaint of ankle pain. All patients complained of chronic ankle pain and swelling that was aggravated by activity without constitutional symptoms. On physical examination, all patients presented with point tenderness over the distal tibia/malleolar regions. Three out of the five cases had a full range of ankle motion; the other two had limited dorsiflexion secondary to pain. All inflammatory laboratory values were within normal limits or only slightly elevated. All initial radiographs of the cases described demonstrated a well-defined radiolucent lesion within the distal tibia. In all cases, patients were treated with curetting, with or without bone graft. Bacterial and fungal cultures were negative in all five patients and no long-term post-operative antibiotics were administered.

Conclusion: In this report, we discuss the clinical, radiographic, and pathologic features of this relatively rare condition in the distal tibia. The distinct clinicopathologic features of the disease process are presented to distinguish Brodie's abscess from a bone tumor.

Keywords: Brodie’s abscess; Staphylococcus infections; Subacute osteomyelitis; abscess; bone diseases; osteomyelitis; tibia.

Figure 1

Key imaging findings of Case 1. Lateral radiograph of the right ankle (a) demonstrating a small geographic subchondral radiolucency on the posteromedial aspect of the distal tibial epiphysis with well-defined margins. Technetium-99 pyrophosphate bone scan (b) demonstrated increased radiotracer uptake around the posteromedial aspect of the distal tibia. Lateral T1-weighted magnetic resonance imaging of the right ankle (c) showing a well-defined lesion with a central area of homogenous, hypointensity (black arrow).

Figure 2

Key imaging findings of Case 2. AP (a) and lateral (b) radiographs of the right ankle demonstrate a serpiginous, radiolucent abnormality in the distal tibial metadiaphysis with well-defined, sclerotic margins. Coronal magnetic resonance imaging (MRI) with contrast (c) demonstrates a characteristic fluid signal within the lesion (arrow). T1-weighted coronal MRI with contrast (d) shows rim enhancement of the lesion (arrow). Axial MRI with contrast (e) further demonstrates the extent of the lesion within the distal tibia.

Figure 3

Key imaging findings of Case 3. AP radiograph of the left ankle (a) demonstrates a radiolucent lesion in the distal tibial epiphysis with well-defined sclerotic margins. Axial computed tomography CT of the left ankle (b) shows a low attenuation abnormality that better delineates the serpiginous borders of the lesion and confirms the absence of bone production, periosteal reaction, or soft-tissue masses.

Figure 4

Histopathology slides of Brodie abscess in case 3. (a) ×40 magnification, (b) ×100 magnification, and (c) ×200 magnification demonstrating inflammatory cell infiltration of the lesion site that is similar to histopathology seen in osteomyelitis.