Primary non-Hodgkin's lymphoma (NHL) is a rare entity. When it does occur, mandibular NHL typically manifests similar to an odontogenic pathology. This results in delayed diagnosis and treatment. We present a 50-year-old female who was erroneously treated for a pyogenic granuloma several months before the correct diagnosis of extranodal primary NHL of the oral cavity was made. Fortunately, the solitary bony lymphoma had not disseminated and management by chemo-radiation allowed for disease eradication and new post-treatment bone formation. The purpose of this report is to describe a rare case of primary NHL of the mandible, explore the diagnosis and work-up and discuss treatment strategies. This case illustrates the need for co-operative diagnostic referrals between physicians and dentists.