Ryoichi Oya

Can flow cytometrically determined DNA ploidy and S-phase fraction predict regional metastasis in squamous cell carcinoma of the oral cavity?

The value of flow cytometric analysis of DNA ploidy and S‐phase fraction (SPF) as an indicator of regional metastasis in oral cancer is currently being debated. Intratumoral heterogeneity makes this problem complex.

Spontaneous regression of recurrent squamous cell carcinoma of the tongue

A 73-year-old man presented with well-differentiated squamous cell carcinoma of the tongue (T3N0N0). After the completion of external beam radiotherapy (32 Gy) and oral tegafur-uracil (UFT) administration, the tumor had clinically disappeared. Two years later, a recurrent lesion was confirmed histologically. Without any specific therapy, the tumor gradually and spontaneously regressed, from 4 months after the recurrence was diagnosed, and it had completely disappeared both clinically and by computed tomography imaging at 1 year and 4 months after recurrence. There was no evidence suggesting regrowth of the disease in the patient at 3 years and 7 months after the histological confirmation of tumor recurrence.

Treatment of Mandibular Fracture-Associated Infectious Pseudarthrosis Accompanied by Osteomyelitis in a Peritoneal Dialysis Patient

Peritoneal dialysis can be performed at home, and the transfer of solutes in the blood and other body fluids is slow compared to hemodialysis, reducing the load on the circulatory organs and lessening the frequency of hospital visits. We encountered a male patient in his 70s on peritoneal dialysis for end-stage renal failure who developed obsolete mandibular fracture-associated pseudarthrosis accompanied by osteomyelitis, which was treated with noninvasive reduction and fixation using circumferential wiring after the resolution of inflammation. The inflammation was resolved by an intravenous drip infusion of ampicillin and lavage of the local region through the fistulated region during hospitalization, and sequestrum was removed under local anesthesia. After the disappearance of drainage from the fistula, the mandibular fracture was fixed with circumferential wiring (noninvasive reduction and fixation) using a mandibular resin base (occlusion is possible). For noninvasive reduction and fixation of a midline fracture, a 6-week fixation period is usually necessary after surgery, but in this case it was fixed for 3 months after surgery because of the presence of infection and bone defect. In jaw bone infection in patients on long-term dialysis, high sensitivity to infection and incomplete cure occur due to a decline in cell-mediated immunity, renal osteodystrophy (ROD), and chronic kidney disease (CKD)-mineral and bone disorder. In the present patient, infection complicated the odontogenic source of infection and fracture, which may have protracted the condition. When jaw bone infection is noted in a patient on long-term dialysis, it is important to closely cooperate with the dialysis physician and select the administration method and dose corresponding to the route of administration and metabolism of antimicrobial agents in order to minimize the influence on the renal function. For the local region, infection control by oral hygiene management and cleaning is important, targeting treatment and management while avoiding the use of any antimicrobial agent.