Costal BCG osteomyelitis presenting as a tumor

We present the case of an 11-month-old male infant who had been BCG vaccinated as a neonate. At the age of nine months, he developed a localized tumor above his right mamilla. The tumor destroyed the fourth rib and infiltrated the surrounding soft tissue. X-ray and CT scan suggested a malignant neoplasm. Histology, however, showed the typical picture of tuberculosis and Mycobacterium bovis (BCG strain) was isolated from the lesion. Thus, the tumor was caused by an unusual presentation of a costal BCG osteomyelitis which was associated with negative findings in the bone scan.