Bone grafting has been clinically used to repair jaw bone defects. Autologous bone grafting is frequently performed and has produced good clinical results as compared with other types of bone grafting. However, the use of this procedure is limited by anatomical reasons such as the site and amount of collected autologous bone. We have experimentally established methods for producing secondary vascularized bone grafts with minimal sacrifice of autologous bone, but with ossification of reliable size and structure. To investigate the possibility of clinically using the produced ectopic bone, a long-term quantitative evaluation was performed with the use of peripheral quantitative computed tomography (pQCT). As control, autologous vessel bundles were produced by abrading the femoral artery and vein of 8 -week-old male Wistar rats and were wrapped in an artificial vessel (e-PTFE membrane). In one experimental group, autologous cancellous bone chips were added to the same treatment as in the control group. In the other experimental group, autologous cortical bone chips were added to the same treatment as in the control group. The animals were killed 6, 9, 12, 18, and 24 weeks after the surgical procedure, and the status of osteogenesis was observed by means of soft X-ray film, histological examination and quantitative evaluation using pQCT. Serial long-term increases in bone density of the produced ectopic bones were present for 24 weeks after the surgical procedure (both experimental groups), with no marked differences from the normal femur. Our results suggest that the produced ectopic bone can be used clinically as a new source of vascularized bone grafts.
The use of distraction techniques to correct the craniofacial skeleton has expanded treatment options for patients with maxillofacial abnormalities and defects. During distraction osteogenesis of tubular bones, newly deposited bone is formed by both in tramembranous and endochondral ossification. The mandible differs from tubular bones in its origin, structure, and function. It is well known that bone formation generally involves intramembranous ossification in the mandible. However, several reports suggest that cartilage is observed not only in tubular bone lengthening but also in mandibular distraction models. It is unclear, however, whether cartilage in the distraction gap is transformed into new bone. This experimental work investigated the morphological features of cartilage during distraction osteogenesis in a rabbit model. Corticotomy was performed just anterior to first premolar, and custom-made devices were applied. The devices were lengthened 0.25mm immediately after surgery, and then repeatedly every 12 hours for 10 days. Four rabbits were sacrificed immediately after lengthening, and 4 more were sacrificed 5 and 10 days after the completion of lengthening. Histological staining, immunohistochemistry, and terminal deoxynucleotidyltransferase dUTP-biotin nick end labeling (TUNEL) were performed. Immediately after lengthening, a substantial amount of cartilage had developed from the central fibrous tissue. The cartilage decreased gradually between 5 and 10 days. Five days after distraction was completed, chondrocytes appeared to be hypertrophic and showed a TUNEL-positive reaction indicating apoptosis. Blood capillaries developed around the cartilage with hypertrophic chondrocytes and increased gradually. Immunoreactivity for type II collagen was not noted around hypertrophic chondrocytes near new bone trabeculae, but type I collagen protein was observed in these cells. Ten days after distraction was completed, TRAP-positive cells were observed around hypertrophic chondrocytes. Five days after distraction was completed, chondroid bone, a tissue intermediate between bone and cartilage, was formed directly by chondrocyte-like cells between the cartilage and new bone trabeculae. These cells showed positive staining for type I collagen. Furthermore, there was no TUNEL expression in chondroid bone. These results indicate that cartilage in the distraction gap was transformed into new bone. Transition of cartilage into bone was classified into two types: endochondral ossification and trans-chondroid bone formation.
Oral leukoplakia is the most common precancerous lesion of the oral cavity and shows a variety of histopathological features, including epithelial dysplasia. It is crucial to analyze the histologic characteristics of dysplastic leukoplakia to determine how the lesion should be treated. We clinicopathogically examined 108 patients given a diagnosis of oral leukoplakia during the past 10 years at the Department of Oral and Maxillofacial Surgery, Kumamoto University Hospital. Their ages ranged from 18 to 85 years (mean age, 60.1), and 52 were male and 56 were female. Common sites of leukoplakia were the tongue (51 cases), gingiva (43 cases), and buccal mucosa (15 cases), and the multiple lesions were seen in 22 cases. Among the 108 cases, squamous cell carcinoma developed in 9 (8%) during follow-up. According to the WHO criteria for epithelial dysplasia, significant differences were observed between non-cancerous leukoplakia and cancerous leukoplakia in the degrees of dysplasia, such as loss of polarity of the basal cells, an increased nuclear-cytoplasmic ratio, drop-shaped rete processes, irregular epithelial stratification, cellular pleomorphism, and nuclear hyperchromatism. The present study suggests that some histologic features of dysplastic leukoplakia predict whether the lesions will progress to cancer or not. Adequate surgical margins and strict follow-up are recommended for oral leukoplakia to detect oral cancer at an early stage.
Polymorphous low-grade adenocarcinoma (PLGA) is a neoplasm arising most commonly in the palatal minor salivary glands. Not established as a distinct entity until 1983, PLGA was often misdiagnosed as adenoid cystic carcinoma or pleomorphic adenoma. This tumor was first reported by Evans and Batsakis (1984) and was adopted as a new entity in the subclassification of adenocarcinoma in the histological classification of salivary gland tumors of the World Health Organization (1991). In this report, we describe a case of PLGA of the palate in a 74-year-old woman. She became aware of palatal swelling, 3 months previously and came to our hospital. A soft, elastic, well-demarcated tumor arising in the left side of the palate, measuring 1.4×1.3cm, and a mucosal ulcer (0.6cm in diameter) were recognized. She underwent partial maxillectomy. There has been no recurrence or metastasis of the tumor as of 1 year after operation.
Pleomorphic adenoma of the retromolar region is rare in childhood. We report a pleomorphic adenoma originating in the left retromolar area of a 10-year-old boy. The patient was conscious of a painless mass in the left retromolar area. The tumor was encapsulated and was easily removed intraorally under general anesthesia. The excised tumor measured 15×10×10mm. Histologic examination showed a capsulated mass with well-differentiated ductal structures and myoepithelial components in a connective-mixoid stroma. Pleomorphic adenoma was diagnosed. Squamous metaplasia and plasmacytoid were also observed. Mature adipose tissue was seen in the stroma. In retrospective studies done at our department, most patients were between the ages of 20 and 60 years. The teens was the smallest age group, (7.3%), and the present 10-year-old patient was the youngest.
A case of spindle cell lipoma extending from the cheek to submandibular region is presented. The patient was a 64-year-old man. Physical examination revealed a tender, smooth, painless mass, measuring 20cm. Computed tomography and magnetic resonance imaging showed a well circumscribed, internally heterogenous mass. This mass was removed surgically. The excised tumor weighed 580g and consisted of two tumors. One measured 18×16×10cm, and the other 4×5×4cm. The histopathological diagnosis was spindle cell lipoma. The postoperative course was uneventful. There have been no signs of recurrence. Spindle cell lipoma is extremely rare in the cheek. Giant spindle cell lipoma such as this case is particularly uncommon. This rare case is presented with some bibliographical comments.
Adenomatoid odontogenic tumor (AOT) is an uncommon odontogenic lesion characterized histologically by ductal structures of epithelial cells and foci of calcification. Typically, these lesions arise in the lateral incisor/canine region in alveolar bone of the maxilla. Rarely, the lesion exhibits aggressive behavior, such as becoming large or extending into the paranasal sinuses. This article describes a case of AOT that extended widely in the maxillary sinus. A 18-year-old woman was referred to our clinic for evaluation of a mixed radiolucent-radiopaque lesion with a well defined border in the right maxillary sinus. A computerized tomographic evaluation demonstrated a defined large lesion that had extended widely in the right maxillary sinus, with thinning the cortical bone of the maxilla. The lesion was associated with an unerupted tooth on the corresponding region of the nasal cavity. An incisional biopsy was performed under local anesthesia. The pathological diagnosis was AOT. Surgery was performed with the patient under general anesthesia. The tumor was enucleated completely via an intraoral approach. There has been no recurrence as of 5 months after surgery.
Hyperplasia of minor salivary glands is an uncommon clinicopathological entity first described by Giansanti et al. in 1971. We encountered a 47-year-old man who had a mass of the lower lip. The patient's medical history included alcoholic hepatitis, gastric ulcer, and HBs antigen positive. He received therapy irregularly at Tagawa Municipal Hospital, without the use of drugs. He recognized a mass of the left lower lip 1 week ago. The mass was covered with normal mucosa, multiple, and measured 2×1cm in longest diameter. Blood examination results were within normal limits without a positive reaction for HBs antigen. He had smoked cigarettes and drunk beer daily for more than 20 years. CT showed a low density mass and MR T 2 imaging showed a high intensity mass in the lower lip. The clinical diagnosis was a benign tumor of the lower lip. Excision was performed by a Nd: YAG laser with the patient under general anesthesia. The pathological diagnosis was salivary gland hyperplasia.
A 54-year-old man was referred to our hospital because of severe trismus. The amount of mouth opening was only 2mm. The patient had sustained blows to the face, and both masseter muscle regions had been strongly grasped. He was unable to open his mouth after the violence. Twenty days after the first injury, he was struck on both sides of the face again. After that, severe trismus occurred. The clinical diagnosis was trismus due to scars of the masseter muscle regions. Incision of the masseteric fascia and abradement of the temporal fascia were carried out, and an interincisal opening of 47mm was achieved at the time of operation. Part of the masseter muscle was resected and examined microscopically. Most of the muscle fibrils had disappeared and been replaced by cicatricial fibrous tissue with hyalinization. Rehabilitation of mouth opening was done with infrared therapy and drug therapy, including muscular relaxants and cicatricial suppressors, postoperatively. A favorable clinical response was achieved, and mouth opening was 40mm 3 months after surgery.
The surgical treatment of a patient with hereditary angioneurotic edema (BANE) is described in the present report. HANE is an autosomal dominant hereditary disease that causes acute and local submucocutaneous edema. It is a very rare disease in Japan and has been reported in only 20 femilies. The subject was a 24-year-old woman with right upper pericoronitis who had been given a diagnosis of HANE at the age of 13 years. Patients with HANE often have fatal laryngeal edema during dental treatment such as extraction of teeth. Therefore, our patient received ginigivectomy after being hospitalized. Postoperatively, she had mild respiratory distress, but it was controlled by intravenous drip infusion of C 1 esterase inhibitor. When treating patients with HANE, we should take sufficient measures to avoid the development of edema, even when treatment is minimally invasive. Furthermore, sufficient preparation for urgent tracheotomy is necessary owing to the risk of laryngeal edema.