Yoshiyuki Uchiyama

Imaging mass spectrometry distinguished the cancer and stromal regions of oral squamous cell carcinoma by visualizing phosphatidylcholine (16:0/16:1) and phosphatidylcholine (18:1/20:4)

Most oral cancers are oral squamous cell carcinoma (OSCC). The anatomical features of OSCC have been histochemically evaluated with hematoxylin and eosin. However, the border between the cancer and stromal regions is unclear and large portions of the cancer and stromal regions are resected in surgery. To reduce the resected area and maintain oral function, a new method of diagnosis is needed. In this study, we tried to clearly distinguish the border on the basis of biomolecule distributions visualized by imaging mass spectrometry (IMS). In the IMS dataset, eleven signals were significantly different in intensity (p < 0.01) between the cancer and stromal regions. Two signals at m/z 770.5 and m/z 846.6 were distributed in each region, and a clear border was revealed. Tandem mass spectrometric (MS/MS) analysis identified these signals as phosphatidylcholine (PC) (16:0/16:1) at m/z 770.5 in the cancer region and PC (18:1/20:4) at m/z 846.6 in the stromal region. Moreover, the distribution of PC species containing arachidonic acid in the stromal region suggests that lymphocytes accumulated in response to the inflammation caused by cancer invasion. In conclusion, the cancer and stromal regions of OSCCs were clearly distinguished by use of these PC species and IMS analysis, and this molecular identification can provide important information to elucidate the mechanism of cancer invasion.

Improved technique for evaluating oral free flaps by pinprick testing assisted by indocyanine green near-infrared fluorescence angiography

In head and neck surgery, free-flap reconstruction using a microvascular anastomosis is an indispensable option after tumor ablation. Because the success of free-flap reconstruction is enhanced by rapid identification and salvage of failing flaps, postoperative monitoring of free flaps is essential. We describe a new technique using indocyanine green (ICG) near-infrared angiography and pinprick testing to monitor intraoral free flaps. A solution of ICG (Diagnogreen, 5 ml) was intravenously injected, and scanning was performed with a near-infrared video camera system. Thirty seconds after ICG injection, a pinprick test was performed by placing a 24-gage needle through the dermis to the subcutaneous fat of the flap. Pinprick testing during ICG fluorescence imaging was performed in 30 patients. Flap perfusion was confirmed in all patients, and all flaps survived postoperatively. ICG fluorescence imaging demonstrated that flap perfusion was maintained.

Treatment of a Large Mandibular Ameloblastoma by Marsupialisation and Marginal Resection Preserves the Mandibular Inferior Border

Abstract Ameloblastomas are benign locally invasive odontogenic tumours. Involvement of the inferior border of the mandible in ameloblastomas usually requires segmental mandibulectomy. This report is of a 72-year-old man with a large mandibular ameloblastoma composed of a large cystic part and a solid multicystic part. A 2-stage operation, consisting of marsupialisation and subsequent marginal resection, enabled the preservation of the inferior mandibular border. There was no evidence of recurrence 55 months after the resection.

Mesenchymal Chondrosarcoma of the Mandible

Abstract This report describes a 33-year-old man diagnosed with mesenchymal chondrosarcoma. The patient was referred with a painless, elastic hard mass in the retromolar region. Radiologically, the tumour presented as an expansion of the right mandibular ramus partly extending to the inferior masseter A segmental mandibulectomy was performed during the initial surgery. Histopathologically, the tumour showed well-differentiated hyaline cartilage tissue in the lobules with cartilaginous islands and small cells. Immunohistochemically, the tumour cells reacted positively to clusters of differentiation99 and S-100 protein. The tumour recurred in the right inferior temporal fossa 3 years after the initial surgery. Although radical right maxillectomy and dissection of the inferior temporal fossa were carried out immediately, the patient developed multiple pulmonary metastases after 10 months.

A case study of temporomandibular joint rheumatoid arthritis with perforation into the external auditory meatus

We report a case of temporomandibular joint rheumatoid arthritis with perforation into the external auditory meatus.The patient was 64-year-old man with progressive rheumatoid arthritis, associated with otopyorrhea and difficulty in mouth opening with pain. He had difficulty with the occlusion and was nearly edentulous jaw for a long time. He was also infected with MRSA in inflammatory granulation tissue in the meatus. He was treated with difficulty by an otorhinolaryngologist, who introduced him to our clinic.We first made and applied dentures. Intermaxillary traction was applied by rigidly fixing the denture with an occlusal pivot to the jaw by means of an osseous screw and circumferential wiring. Antibiotics active against MRSA in the granulation tissue were given. After intermaxillary fixation for 2 weeks and intermaxillary elastic traction for the next 2 weeks, the TMJ space was enlarged and the granulation tissue in the meatus disappeard. Epithelialization successfully occurred. We finally attempted occlusal adjustment by raising the bite of the upper and lower dentures.We fortunately treated the case successfully, but long-term observation is necessary.