Clinical study of keratocystic odontogenic tumors

The odontogenic keratocyst (OKC) was originally classified as a developmental cyst, and OKCs were histologically divided into orthokeratotic (O-OKCs) and parakeratotic (P-OKCs) types. Clinical features differ between O-OKCs and P-OKCs with P-OKCs having a tendency to recur after surgical treatment. According to the revised histopathological classification of odontogenic tumors by the World Health Organization (2005) , the term keratocystic odontogenic tumor (KCOT) has been adopted to describe P-OKCs. In this retrospective study, we examined 186 KCOTs treated at the Maxillofacial Surgery Department of the Tokyo Medical and Dental University Hospital from 1981 through 2005. The patients ranged in age from 7 to 85 years (mean, 32.7) and consisted of 93 males and 93 females. The most frequently treated areas were the mandibular molar region and ramus. The majority of KCOTs in the maxillary region were treated by enucleation and primary closure. The majority of KCOTs in the mandibular region were enucleated, and the wound was left open. Marginal resection was performed in the 4 patients with large lesions arising in the mandible. In patients who were followed for more than a year, recurrences were observed in 19 of 120 lesions (15.8%) . The recurrences were found at the margins of the primary lesion in contact with the roots of the teeth or at the upper margins of the mandibular ramus. Clinicians should consider aggressive treatment for KCOTs because the recurrence rate of P-OKCs is higher than that of other cyst types such as O-OKCs, dentigerous cysts, primordial cysts that were non-keratinized, and slightly keratinized stratified squamous epithelium. Although more aggressive treatment is needed for KCOTs as compared to other cystic lesions, it is difficult to make a precise diagnosis preoperatively on the basis of clinical features and X-ray imaging. Therefore, preoperative biopsy is necessary for selecting the appropriate treatment for patients with cystic lesions.

Complications and Outcome of Free Flap Transfers for Oral and Maxillofacial Reconstruction / Oral Science International

Microvascular free flap transfers have become a preferred reconstructive technique; however, rare complications may still prove devastating. This study reviewed 213 consecutive free-tissue transfers in order to assess the incidence and causes of complications in patients undergoing microvascular free flap reconstruction in the oral and maxillofacial region. In most cases, reconstruction was undertaken after resection of a malignant tumor. The flap donor sites were the radial forearm (n=111), rectus abdominis (n=88), scapula (n=13), and latissimus dorsi (n=1). The superior thyroid artery and the external jugular vein were commonly used as recipient vessels for anastomosis. The overall flap success rate was 99%. There were 7 cases of postoperative vascular thrombosis (6 venous and 1 arterial), constituting 3.3% of the entire series. Five flaps were salvaged, representing a 71.4% successful salvage rate in cases of vascular complications. Most of the successful salvage attempts were made within 24 hours of the end of the initial operation, and the successful salvage rate for re-exploration was 100%. Finally, the total flap loss rate was 0.9% and the partial flap loss rate was 2.3%. We conclude that early re-exploration should be the first choice for management of vascular compromised flaps. Complications at the donor site occurred in 17 cases (8.0%), the most common complication of which was partial skin graft loss after harvesting a radial forearm flap (n=10; 9.0%). Recipient and donor site morbidity was limited and considered acceptable.

Simultaneous Assessment of Cyclin D1 and Epidermal Growth Factor Receptor Gene Copy Number for Prognostic Factor in Oral Squamous Cell Carcinomas / Oral Science International

Cyclin D1 gene (<i>CCND1</i>) numerical aberrations are independent prognostic indicators of head and neck squamous cell carcinomas (HNSCCs). High epidermal growth factor receptor gene (<i>EGFR</i>) copy number is associated with poor prognosis in lung cancer, but such findings are controversial in oral SCCs (OSCCs). We analyzed copy number status in <i>CCND1</i> and <i>EGFR</i> in OSCC patients and its association with clinical outcome.<i>EGFR</i> and <i>CCND1</i> statuses were analyzed in 85 OSCC patients by fluorescence <i>in situ</i> hybridization (FISH) of specimens obtained by fine-needle aspiration biopsy.<i>CCND1</i> numerical aberration was found in 35 of 85 tumors (41%), and aberrant <i>EGFR</i> copy number was observed in 36 (42%). Gene amplification (GA) was dominant among <i>CCND1</i> copy number changes (14/35:40%). Balanced trisomy (BT) was the most frequently observed <i>EGFR</i> aberration (17/36:47%). In a multivariate Cox's proportional hazards analysis, <i>CCND1</i> GA was correlated with disease-free survival (<i>P</i><0.001), whereas <i>EGFR</i> BT was significantly correlated with overall survival (<i>P</i>=0.001). Patients with a combination of <i>CCND1</i> GA and/or <i>EGFR</i> BT had significantly poorer clinical outcome.<i>CCND1</i> and <i>EGFR</i> copy number changes were frequent in OSCC and had differing aberration patterns. <i>CCND1</i> GA and <i>EGFR</i> BT statuses by dual-color FISH were the predominant predictors of clinical outcome. Further investigation is needed to determine the implications for EGFR inhibitor therapy in OSCC.