# A Rare Cause of Recurrent Left Knee Pain in an Adolescent Male: A Case Report of Distal Femoral Brodie's Abscess

## TL;DR

This case report describes a rare instance of a Brodie's abscess in a healthy teenager's knee, highlighting the challenges in diagnosis and the importance of timely treatment.

## Contribution

The paper presents a rare clinical case of distal femoral Brodie's abscess in a previously healthy adolescent.

## Key findings

- The patient's chronic knee pain was caused by a Brodie's abscess, initially misdiagnosed due to nonspecific symptoms.
- MRI findings, including the 'penumbra sign,' were key to confirming the diagnosis.
- Early recognition and treatment prevented complications and led to a favorable outcome.

## Abstract

Brodie's abscess, a subacute form of osteomyelitis, is characterized by localized symptoms and can be challenging to diagnose due to its nonspecific clinical presentation. We report a rare case of distal femoral Brodie's abscess in a healthy child, emphasizing the diagnostic intricacies and management. A 15‐year‐old previously healthy patient presented with chronic left knee pain of insidious onset and progressive nature. Conservative measures were initially employed, leading to transient symptom resolution. Clinical examination revealed limited flexion, and imaging demonstrated a well‐corticated osteolytic lesion with a sclerotic rim on the distal femur, along with the characteristic “penumbra sign” on magnetic resonance imaging (MRI). Brodie's abscess can mimic benign conditions, leading to delayed diagnosis. Clinicians should maintain vigilance when evaluating patients with unexplained joint pain, especially in the absence of systemic symptoms. Early recognition and appropriate management, as exemplified in this case, are crucial for preventing complications and ensuring a favorable outcome. This report contributes to the understanding of this rare condition and highlights the significance of timely intervention in Brodie's abscess cases.