RESUMO
Aggregatibacter actinomycetemcomitans (Aa), a Gram-negative coccobacillus commonly associated with endocarditis, poses a rare diagnostic challenge in pediatric cases. The presentation of two pediatric cases-myositis and chest mass-highlights novel aspects, including unusual symptom presentations in children which can be mistaken for malignancy. The limited sensitivity of standard blood tests complicates diagnosis, leading to delayed diagnosis and treatment. Representative samples must be taken, especially if blood cultures are negative. Despite advances in detection methods, diagnosing Aa infection remains difficult due to its rarity in children and variable clinical presentation. In conclusion, a comprehensive understanding of Aa infection in children is essential for early and effective diagnostic and therapeutic management.