RESUMO
BACKGROUND: Actinomycosis is a rare infection, frequently misdiagnosed as a neoplasia. This chronic and granulomatous disease is caused by Actinomyces israelii species. Cervicofacial actinomycosis occurs in 60% of cases and the diagnosis is commonly made by histopathology study. CASE DESCRIPTION: We report a case of fronto-orbital osteomyelitis initially misdiagnosed as a cranial bone meningioma, but later proved to be a case of actinomycosis. 99mTechnetium (99mTc) three-phase bone single-photon emission computed tomography/computed tomography (SPECT/CT) and 99mTc-ubiquicidin (UBI) 29-41 bone SPECT/CT scans were performed to corroborate the control of the infection. CONCLUSION: Craniofacial actinomycosis is the most common presentation of actinomycosis. However, it continues to be a rare and difficult disease to diagnose and is often confused with a neoplastic process. The 99mTc-UBI 29-41 bone SPECT/CT scan could be an auxiliary noninvasive diagnostic alternative and a follow-up method for these patients.