Presentation symptoms of PBL include localized bone pain and sometimes the presence of a palpable mass. In the mandible, the main symptoms of PBL are pain, swelling, numbness, tooth mobility and cervical lymphadenopathy. In this case, the patient had what appeared to be dental caries, which were previously evaluated by a dentist. Initial diagnosis is often wrong; Limb et al. suggested that the mean time to achieve a correct diagnosis of PBL is 8 months .
The role of FDG-PET in the management of patients with lymphoma is clear. It has the potential to influence both the initial choice of chemotherapy and alterations to the management of the disease based on the response to therapy . In our case, the 18FDG PET/CT provided staging information of the lymphoma and revealed the presence of a hypermetabolic lesion on the thyroid that was finally diagnosed as papillary carcinoma.
Thyroid incidentalomas are defined as newly identified thyroid lesions encountered during imaging studies. As 18FDG PET/CT is becoming a more common imaging modality, the incidence of thyroid incidentalomas is also increasing. A few retrospective studies have shown the prevalence of this finding to be approximately 2.3% . Kang et al. studied the possibility of differentiating a malignant from a benign lesion with SUV. While a SUV > 9 suggested a higher likelihood of cancer, the authors concluded that a pathological confirmation is required.
The value of FDG-PET in patients with differentiated thyroid cancer is under review. FDG-PET has a clear role in I131-negative thyroid cancer and follow-up, but it should not be performed in patients with a stimulated Tg < 10 μgr/L because of its low sensitivity [10, 11].
The treatment and optimal management of patients with PBL are unclear because of the low incidence of this pathology. Few retrospective studies have examined the clinical characteristics, treatment and outcome of these patients. The published studies span many years, during which time staging techniques and treatment modalities have changed. Despite the heterogeneity of the treatment in the literature, it seems clear that a combined modality therapy of chemotherapy with radiotherapy leads to better results than a single modality of treatment [2, 12]. Someya et al. reviewed the literature regarding the treatment of PBL of the mandible and concluded that radiotherapy alone was not enough for tumor control for stage I + II disease and that combination chemotherapy might be needed . This conclusion is consistent with the results of studies on patients with early-stage non-Hodgkin lymphoma [14, 15].
Rituximab added to six cycles of CHOP is an effective treatment for young patients with good-prognosis DLBCL  and is currently the gold standard treatment for these patients. This regimen results in improvement of both event-free survival and survival. The excellent results achieved in patients with stage I without bulky disease suggest that the addition of rituximab may lead to a reduction in chemotherapy cycles and may therefore be an option for the future treatment of these patients.