Role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in predicting pathological response to preoperative super-selective intra-arterial chemoradiotherapy for advanced squamous cell carcinoma of the mandible.

INTRODUCTION: Although chemoradiotherapy (CRT) for oral squamous cell carcinoma (SCC) has been shown to preserve organ function and improve cosmetic results, site-specific data, especially mandible, are limited. The aim of this study was to evaluate the predictability of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) on response to super-selective intra-arterial CRT for advanced SCC of the mandible. METHODS: Fifteen patients with advanced SCC of the mandible underwent super-selective intra-arterial CRT followed by radical resection. Maximum standardized uptake value (SUVmax) of the mandibular lesion was evaluated with FDG-PET/CT before and after CRT. The SUVmax before and after CRT was defined as pre-SUVmax and post-SUVmax, respectively. The difference between pre- and post-SUVmax was calculated as SUVmax reduction rate to evaluate treatment response of the mandibular lesion. Each SUVmax reduction rate and surgical specimen of the corresponding lesion was analyzed to evaluate an accuracy of the modality for predicting pathological response. RESULTS: The median of pre-SUVmax was significantly lower than that of post-SUVmax (p = 0.001). Of the 15 patients, 6 had a pathological complete response (pCR) and 9 had a non-pCR. Neither pCR patients nor non-pCR patients showed significant difference of the median of SUVmax between pre- and post-CRT (pre-CRT p = 0.099 post-CRT p =0.074). The SUVmax reduction rate in patients with pCR was significantly higher than that with non-pCR (p = 0.002). Receiver operating characteristic analysis revealed that the optimal cut-off point of the reduction rate was 64.7%, with 83% sensitivity and 100% specificity. CONCLUSIONS: These results concluded that SUVmax reduction rate can predict pathological complete response of preoperative super-selective intra-arterial CRT for advanced SCC of the mandible.

Mandibular Ewing sarcoma with chromosomal translocation t(21;22)(q22;q12).

Ewing sarcoma (ES) is a primary bone malignant neoplasm and is the second most common primary malignancy of the bone found in childhood and adolescence after osteosarcoma. ES has an annual frequency in the population younger than 20 years of approximately 2.9 per million. ES occurs most frequently in the long bones of the extremities and pelvis and very rarely in the jaw. Recently, it was revealed that chromosomal translocation t(11;22)(q24;q12), which fuses the EWS gene on chromosome 22 and the FLI-1 gene on chromosome 11, occurs in most cases of ES. We report here a rare case of mandibular ES in a 10-year-old child with chromosomal translocation t(21;22)(q22;q12) in which the EWS gene is fused with the ERG gene on chromosome 21.

Actinomyces-associated calcifications in a dentigerous cyst of the mandible.

Actinomyces-associated lesions in the jaw, such as radicular cyst and osteomyelitis, have been reported by many authors. The lesions are caused by infection from peripheral sites and can be seen to contain Actinomyces druses on pathologic examination. To our knowledge, no previous reports have described Actinomyces-associated calcification in the jaw, although the lesions in the jaw often include druses. We report here a rare case of Actinomyces-associated calcifications in a dentigerous cyst of the mandible.

Cartilaginous choristoma of the lower lip.

Choristoma is a tumor-like mass consisting of normal cells in an abnormal location. Cartilaginous choristoma, which is composed of ectopic cartilaginous tissue, very rarely presents in the oral cavity and most commonly in the tongue. Here we report an extremely rare case of cartilaginous choristoma of the lower lip.

Thyrolinguofacial trunk arising from the carotid bifurcation determined by three-dimensional computed tomography angiography.

It is recognized that the branches of the external carotid artery (ECA) can show variation, but the presence of a thyrolinguofacial trunk is extremely rare and always originates from the ECA. We report a case of the thyrolinguofacial trunk arising from the carotid bifurcation (CB) on the left side in a 76-year-old man with advanced tongue cancer, as revealed by three-dimensional computed tomography angiography for vascular mapping of the carotid vessels prior to superselective intra-arterial catheterization. The thyrolinguofacial trunk arose 1.6 mm below the CB from the anterior surface of the left CB. The inner diameter of the thyrolinguofacial trunk at origin was 4.4 mm and the angle between the thyrolinguofacial trunk and CB was 128°. After a 1.7-mm course, the trunk divided into the superior thyroid artery and a linguofacial trunk, the inner diameters of which were 1.5 and 3.4 mm, respectively, at origin. The angle between the two arteries was 88°. After a 9.8-mm course from the bifurcation, the linguofacial trunk divided into the lingual artery and facial artery, the inner diameters of which were 1.8 and 1.9 mm, respectively, at origin. The angle between the two arteries was 61°. It is important to recognize such an anatomic variation of the branches of the ECA prior to superselective intra-arterial catheterization or microsurgical reconstruction for head and neck cancer.

18F-fluorodeoxyglucose-positive Warthin tumor in a contralateral cervical lymph node mimicking metastasis in tongue cancer staging with PET/CT.

We report 18F-fluorodeoxyglucose-positive Warthin tumor in a contralateral cervical lymph node mimicking metastasis in tongue cancer staging with positron emission tomography/computed tomography.