Inflammation defined as the process by which the body responds to an injury or infection, and it is triggered by the innate immune system. Although the innate immune system has been recognized as the first line of defense against foreign pathogens, inflammatory responses also occur in the absence of infection and these are referred to as “sterile inflammation”. Increasing evidence indicates that several types of sterile inflammation in diseases are mediated through newly discovered innate immune pathways known as NLRP3 inflammasomes. NLRP3 inflammasomes are intracellular multi-protein complexes that serve as molecular platforms to induce caspase-1 activation and interleukin-1β secretion, leading to inflammatory responses. Recent investigations by our and other groups demonstrated that NLRP3 inflammasomes have been implicated in the pathogenesis of cardiovascular and lifestyle-related diseases, such as atherosclerosis, myocardial infarction, chronic kidney disease, gout, type 2 diabetes mellitus, and metabolic syndrome. Therefore, NLRP3 inflammasomes are considered to be a novel target for the treatment of these disorders.

We often observed that ¹⁸F-FDG accumulation in gingival cancer with bone resorption was higher than that in tongue cancer. In this study, we statistically compared accumulation of ¹⁸ F-FDG in gingival cancer with bone resorption with accumulation in tongue cancer. We also compared it with ¹⁸F-labeled choline (¹⁸F-choline) PET to clarify the characteristics of ¹⁸F-FDG accumulation in bone resorption.

The subjects were 57 patients with gingival cancer and 34 patients with tongue cancer. Histologically, all cases were squamous cell carcinoma. ¹⁸F-FDG and ¹⁸F-choline accumulations were evaluated using the maximum standardized uptake value (SUV).

Comparison of ¹⁸F-FDG SUV between tongue cancer and gingival cancer without bone resorption showed no significant difference; however, the comparison between tongue cancer and gingival cancer with bone resorption resulted in values of 6.6 and 10.4, respectively, showing a significantly higher ¹⁸F-FDG SUV in gingival cancer accompanied by bone resorption (p = 0.001). The SUV of ¹⁸F-choline in tongue cancer was similar to that of ¹⁸F-FDG, but unlike with ¹⁸F-FDG, the SUV was not significantly higher in gingival cancer with bone resorption.

The mean ¹⁸F-FDG PET SUV was higher in gingival cancer with bone resorption than in tongue cancer, although this finding was not observed with ¹⁸F-choline. It was assumed that the high ¹⁸F-FDG SUV was due to accumulation in osteoblasts and osteoclasts involved in bone metabolism in addition to cancer stromal cells.

Ossifying fibroma, occuring in the jawbone centrality, is a neoplastic growth composed of fibrous tissue with a similar calcification to that of the bone and cementum. Here, we report a case of ossifying fibroma involving the inferior border of the mandible in a 19-year-old female patient, which was reconstructed immediately via jawbone tumorectomy and iliac transplantation of particulate cancellous bone and marrow. Initially, the case was regarded as an adaptation of a segmentectomy based on the size of the tumor. However, it was possible to maintain the structure of the jaw and to avoid esthetic defects, by preservation of the lingual side of the jaw and an inferior border cortical bone. There was no evidence of a recurrence of the tumor during the 4-year follow-up.