Kazunari Karakida

Ameloblastic carcinoma, secondary type: a case report

Malignant variants of ameloblastoma include metastasizing ameloblastoma, which microscopically appears benign but has metastasized and ameloblastic carcinoma that exhibits malignant histopathologic features. Ameloblastic carcinoma is classified into 2 types: a primary odontogenic malignancy and a secondary type resulting from malignant transformation of ameloblastoma. Most secondary ameloblastic carcinomas result from malignant transformation of a primary lesion after repeated postsurgical recurrences. Therefore it is rare to find an untreated secondary type presenting with histologic features of malignant transformation from an earlier benign lesion. We experienced a rare case of ameloblastic carcinoma, secondary type which might arise in an untreated ameloblastoma. The mechanism by which a preexisting benign ameloblastoma goes through a malignant transformation is also described.

Determination of deep surgical margin based on anatomical architecture for local control of squamous cell carcinoma of the buccal mucosa

Of all oral squamous cell carcinomas, squamous cell carcinomas of the buccal mucosa (BSCC) are most associated with poorest prognosis. In particular, patients treated with surgery alone are reported to experience frequent local failures. This is considered to result from the surgeons determination of the deep surgical margin for resection based on palpation alone when performing BSCC surgery. Therefore, an objective system for classifying the depth of invasion of a tumor appears to be necessary in order to improve the results of BSCC treatment. While current general practice is to treat based on tumor thickness, we would like to emphasize the importance of how far down the cheek wall layer the tumor has invaded. We performed surgery by classifying the depths of tumor invasion in relation to the buccinator. Depth of tumor invasion was assessed mainly using ultrasonography (US). The tumor was defined as D1 when it extended to the mucosal (m) and submucosal layers (sm). In these cases, the tumor was resected, while the buccinator was spared. The tumor was defined as D2 when it extended to the buccinator, but, based on US, muscle continuity was preserved, and the tumor was resected to include the buccinator and its overlying fascia. When the tumor had spread to the buccinator or invaded subcutaneous or cutaneous tissue it was classified as D3 and resection included the skin. The disease-specific survival rate of BSCC when treated based on our classification was 73.7% and the local control rate was 89.5%. These results are superior to those based on surgery alone and this therapeutic modality was considered to be useful.

Association of hepatocyte growth factor expression with salivary gland tumor differentiation.

To clarify the significance of hepatocyte growth factor (HGF) expression in salivary gland tumors, HGF distribution in tissue sections and HGF concentrations in saliva and serum were examined. Sixty salivary gland adenomas, 61 salivary gland carcinomas and three autopsy fetuses were studied. Hepatocyte growth factor expression was observed in the duct‐type luminal cells by immunohistochemical staining and in situ hybridization. However, HGF failed to be expressed in acinar cells and myoepithelium of normal salivary gland tissue. Hepatocyte growth factor tended to be expressed more intensely in benign salivary gland tumors than in malignant salivary gland tumors (P < 0.0001). In highly malignant tumors, the expression was limited in some cases. Salivary and serological HGF concentrations of 18 patients, comprised of 12 benign cases and six malignant cases, were analyzed before and after operation by an ELISA system. The concentrations were distinctly elevated after operation, in both saliva and serum, compared to before operation (P < 0.0005). However, there were no significant relationships between HGF concentration and histology, age, gender, size or location. Our findings suggest that HGF may play an important role in the development of salivary ducts of normal salivary tissues and differentiation of ductal structures of their neoplasms, while HGF kinetics in saliva and serum would be less likely to reflect the neoplastic character, benign or malignant.

Postoperative follow-up strategy in patients with oral squamous cell carcinoma.

PURPOSE The duration of follow-up after treatment of oral squamous cell carcinoma and the frequency of routine visits are based on common usage rather than evidence-based practice. The purpose of this study was to determine the appropriate postoperative routine follow-up program in patients with oral squamous cell carcinoma. PATIENTS AND METHODS Three hundred four cases treated curatively mainly by surgery at Tokai University Hospital from 1994 to 2004 were analyzed. A secondary event was defined as a local recurrence, a regional recurrence, a distant metastasis, or a second primary cancer. To evaluate the follow-up program, data on the first tumor recurrence or first second primary tumor in the head and neck region or elsewhere in the body were used. Overall survival rate, disease-specific survival rate, relapse-free rate, and cumulative risk of developing a second primary cancer were estimated by the Kaplan-Meier product limit method. RESULT All relapse cases were detected within 3 years postoperatively, of which 86.3% were detected within 1 year. Most relapses were in the neck, and regional recurrences had a dismal salvage rate. Second primary cancers were constantly detected 1 to 10 years postoperatively. CONCLUSION Follow-up should be performed more frequently in the first year, with 2 weekly follow-ups with monthly ultrasound examinations, and should be continued after 3 years to exclude the development of second primary cancers.

A case of brain abscess extended from deep fascial space infection

A case of brain abscess in the temporal lobe caused by direct intracranial extension of deep neck abscess is described. The abscess also spread to the orbital cavity through infraorbital fissure. The possible etiology of this case might be dental surgery. The diagnostic imaging clearly showed the routes of intracranial and -orbital extension of parapharyngeal and masticator space abscesses. From the abscess specimens, oral streptococci, anaerobic streptococci, and anaerobic gram-negative bacilli were isolated. Antimicrobial susceptibility testing of isolates showed that some Prevotella and Fusobacterium strains had decreased susceptibility to penicillin, and these bacteria produced beta-lactamase. The bacteria from the deep neck abscess were consistent with those detected from the brain abscess. Proper diagnosis, aggressive surgical intervention, and antibiotics chemotherapy saved the patient from this life-threatening condition.

Development of follicular lymphoma of the cervical lymph nodes in a postoperative patient with tongue cancer.

Patients with head and neck squamous cell carcinoma are at an increased risk of developing second malignancies. Most commonly, these second primary malignancies are squamous cell carcinoma of the head and neck region, but also noted are esophageal cancer or lung cancer. Hematologic malignancies are uncommon second malignancies. Diagnosis can be challenging, particularly when a patient suffers metastases of squamous cell carcinoma to the cervical lymph nodes in addition to synchronous or metachronous malignant lymphoma that originates in the cervical lymph nodes. This article describes a case of primary follicular lymphoma in the cervical region that was discovered during a postoperative follow-up after partial glossectomy and neck dissection for tongue cancer.

Necrotizing fasciitis of the neck due to an odontogenic infection: A case report

Deep fascial space infections of the neck are most frequently odontogenic in origin. We describe a case of odontogenic infection of the mandible which extended to the lateral pharyngeal space and resulted in a severe life-threatening necrotizing fasciitis of the neck. A 69-year-old nondiabetic male complained of dysphagia and a severe toothache of the lower left molar and was transported to the emergency ward. A CT scan revealed swelling of the peritonsillar, lateral pharyngeal and masticator space with narrowing of the airway of the middle pharynx. The patient underwent a tracheotomy with surgical drainage. The strap muscles, including the fascia, of the neck were necrotic. He was treated with a combination of ampicillin and clindamycin-2-P. On the second postoperative day, the patients platelet count fell to 20,000/mm3. The patient was transfused with platelet concentrate, and given gamma globulin and gabexate mesilate, and his predisseminated intravascular coagulation (DIC) status improved. However, on the eight post operative day, progressive tissue necrosis of the face and neck was observed. Panipenem betamipron was started and continued for 20 days. A second extensive surgical debridement of the neck and face was carried out, and the patient ultimately recovered.Prevotella buccae, Streptococcus intermedius, Lactobacillus fermentum, L. casei, L. catenaforme, L. acidophilus, andBifidobacterium sp. were isolated from either the peritonsillar, submandibular, lateral pharyngeal or carotid space abscesses. We emphasize the importance of proper diagnosis, early surgical intervention and systemic antimicrobial chemotherapy to control this aggressive infectious disease.

Identification of oral bacteria by 16S rRNA gene analysis in elderly persons requiring nursing care

After incubation of saliva from 58 semi-bedridden elderly persons, the cultures were identified based on the 16S rRNA gene base sequence to compare the identification by the conventional culture method. As a result, the 16S rRNA gene base sequence of 198 strains identified by the culture method showed 98.5% or more homology in some of the Human Oral Microbiome database, and the identification of bacterial species and genus was possible. When an organism identified by the 16S rRNA gene sequencing method was compared with that by the culture method, the concordance rates were 54.5% at the genus level and 35.9% at the species level. Streptococcus mitis strains most frequently isolated from saliva that were identified by the culture method were identified as the same species by the 16S rRNA gene sequencing method (32/35), and all the 11 Streptococcus salivarius strains identified by the culture method were identified as the same species by the 16S rRNA gene sequencing method. All the strains identified as Streptococcus anginosus group by the culture method and 8 of the 9 strains identified as Prevotella species by the culture method were identified as the same group and genus by the 16S rRNA gene sequencing method. When an oral microbial flora test with saliva samples from elderly persons is performed, the 16S rRNA gene sequence identification enables us to identify major indigenous bacteria and pathogenic bacteria and is considered useful as a means of supplementing the conventional culture method.

Fatal Bleeding in Conjunction with Mandibular Medication-related Osteonecrosis of the Jaw (MRONJ)

Here, we report a case of fatal bleeding in conjunction with mandibular medicationrelated osteonecrosis of the jaw (MRONJ). A 75-year-old Japanese man was referred to our department with osteonecrosis of the jaw due to bisphosphonate (BP) for multiple bone metastases from prostate cancer. Aggressive surgical intervention was ruled out due to a poor prognosis in terms of life expectancy. Death occurred due to hemorrhagic shock resulting from massive oral bleeding caused by necrosis of the mandible. Numerous reports have suggested that jaw necrosis is induced not only by BP, but also RANKL antibody, steroids, and molecularly-targeted agents. This suggests that the number of cases of MRONJ is likely to increase among elderly patients in whom general health is already poor. The American Association of Oral and Maxillofacial Surgery recommends aggressive treatment only in cases of stage 3 disease. Therefore, such a therapeutic strategy may only be available for cases of jaw necrosis in which the general health status of the patient is otherwise good. To prevent a life-threatening outcome in cases of MRONJ, physicians, who are responsible for determining the drug strategy, should cooperate with oral surgeons in determining the best therapeutic strategy.