Tuberculosis is considered an emerging disease worldwide; in the last 10 years, its incidence has increased to more than 9.6 million cases of active tuberculosis. In 2014, it resulted in 1.5 million patient deaths. However, oral presentation with bone involvement occurs in less than 3% of all reported cases and rarely arouses clinical suspicion on initial presentation. A 15-year-old Mexican girl who had a previous diagnosis of neurofibromatosis presented to our hospital with pain and swelling in the region of the left mandibular body since November 2011. A clinical examination revealed pain in the mandibular region, a mass of soft consistency that seemed to involve bone, and a fistula with discharge of intraoral purulent material. Additionally, tachycardia and hyperthermia were observed. The left submental and submandibular regions had a 12-cm-diameter swelling, which was well-delineated and nonerythematous. The final diagnosis was established by real-time polymerase chain reaction. The final diagnosis of rare cases of tuberculous osteomyelitis in the jaw can be established by deoxyribonucleic acid (DNA) identification of Mycobacterium tuberculosis in the lesion. Simple and fast complementary diagnosis by real-time polymerase chain reaction is a fundamental approach to establishing early and effective pharmacological and surgical treatment.