Immunohistochemical staining patterns of cytokeratins 13, 14, and 17 in oral epithelial dysplasia including orthokeratotic dysplasia.

Diagnosis of the exact grade of oral epithelial dysplasia is difficult, and interobserver variations in grading are common. The aim of this study was to investigate the expression patterns of cytokeratins (CKs) in dysplastic oral epithelia, to identify useful double immunostaining diagnostic markers. Immunoexpression of CK13, CK14, CK17, and Ki-67 were investigated in 21 normal epithelial specimens and 146 epithelial dysplasia specimens. In epithelial dysplasia specimens, orthokeratotic dysplasia (OKD) was identified using CK10 immunostaining. Most mild dysplasia specimens were CK13+ and CK17-. In moderate dysplasia, CK13 expression tended to be lower and CK17 expression tended to be higher than in mild dysplasia. All carcinoma in situ (CIS) specimens were CK17+. In differentiated type CIS specimens, CK13 expression was weakly positive. Most epithelial dysplasia specimens were CK14+. There were no significant differences in the expression patterns of CKs between OKD and non-OKD specimens in any of the grades of dysplasia. These results indicate that CK14 expression can be used to detect early epithelial dysplasia, and that CK13 and CK17 expression are useful for detecting neoplastic changes.

Diagnostic usefulness of ¹8F-FAMT PET and L-type amino acid transporter 1 (LAT1) expression in oral squamous cell carcinoma.

PURPOSE: L-[3-(18)F]-α-Methyltyrosine ((18)F-FAMT) was developed as an amino acid tracer for PET imaging to provide better specificity than 2-[(18)F]fluoro-2-deoxy-D-glucose ((18)F-FDG) PET for cancer diagnosis. We investigated the diagnostic usefulness of (18)F-FAMT in oral squamous cell carcinoma (OSCC). The correlation between tumour uptake of (18)F-FAMT and L-type amino acid transporter 1 (LAT1) expression was determined. METHODS: The study group comprised 68 OSCC patients who underwent both (18)F-FAMT and (18)F-FDG PET. Resected tumour sections were stained by immunohistochemistry for LAT1, CD98 and Ki-67, and microvessel density was determined in terms of CD34 and p53 expression. RESULTS: The sensitivity of primary tumour detection by (18)F-FAMT and (18)F-FDG PET was 98 % and 100 %, respectively. The sensitivity, specificity and accuracy of (18)F-FAMT PET for detecting malignant lymph nodes were 68 %, 99 % and 97 %, respectively, and equivalent values for (18)F-FDG PET were 84 %, 94 % and 94 %, respectively. The specificity and accuracy of (18)F-FAMT were significantly higher than those of (18)F-FDG. The uptake of (18)F-FAMT was significantly correlated with LAT1 expression, cell proliferation and advanced stage. The expression of LAT1 in OSCC cells was closely correlated with CD98 levels, cell proliferation and angiogenesis. CONCLUSION: (18)F-FAMT PET showed higher specificity for detecting malignant lesions than (18)F-FDG PET. The uptake of (18)F-FAMT by OSCC cells can be determined by the presence of LAT1 expression and tumour cell proliferation.

Treatment strategy of a huge ameloblastic carcinoma.

Ameloblastic carcinoma is a very rare malignant odontogenic tumor. We report a case of secondary-type ameloblastic carcinoma that extended transversally over almost half of the side of the face. Malignant transformation and identification of the malignant region in the large tumor were achieved using L-3-[F]fluoro-α-methyltyrosine (FAMT)-positron emission tomography (PET); FAMT is transported into cancer cells by L-type amino acid transporter 1 and shows high specificity for malignant tumors. The malignant region determined by microscopic evaluation of resected samples was similar to the region showing high FAMT uptake in PET. Using preoperative FAMT-PET and magnetic resonance imaging, we were able to achieve total resection of the very large tumor, while avoiding excessive resection that could cause severe functional loss or a poor aesthetic facial appearance. We used a modified Weber-Fergusson incision along the nasolabial fold to the labiajugal fold and reconstruction with a pectoralis major muscle flap, and this gave a good aesthetic outcome. Safe surgical resection was possible because preoperative three-dimensional computed tomography angiography was used to identify the position of the main trunk of the external carotid artery, which was closely aligned with the tumor in a posterior direction in the infratemporal fossa region.

Ameloblastic carcinoma developing in preexisting ameloblastoma with a mutation of the p53 gene: a case report.

OBJECTIVE: Ameloblastic carcinoma is a rare malignant odontogenic tumor. Here we present a case of a large ameloblastic carcinoma, which developed in a preexisting ameloblastoma in the right submandibular region. STUDY DESIGN: The patient was an 84-year-old woman who had received several surgical procedures for ameloblastoma, including a segmental mandibulectomy. The dimensions of the tumor were 12 × 8 × 5 cm, and both benign ameloblastoma and ameloblastic carcinoma were observed histologically. Based on histologic diagnosis, immunohistochemical staining and sequence analysis for p53 were performed. RESULTS: Overexpression of p53 was observed only in the ameloblastic carcinoma. Additionally, a mutation of the p53 gene (TP53) in exon 5 was found by sequence analysis in the ameloblastic carcinoma. CONCLUSIONS: This is the first case of ameloblastic carcinoma with a mutation of the p53 gene that has been associated with carcinomatous transformation.

Bizarre parosteal osteochondromatous proliferation of the maxilla: a case report.

Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare benign lesion of bone, known as Nora's lesion. The lesion often behaves like a malignant tumor, clinically and microscopically. BPOP usually occurs in the small tubular bones of the hands and feet, and a lesion arising in the oral and maxillofacial region is extremely rare. In this report, we present a case of BPOP arising in the maxilla of an adult woman, in the absence of trauma. After the initial lesion was excised, the patient began orthodontic treatment. The lesion recurred twice, both times appearing in almost the same location. Finally, the lesion was excised via marginal resection of the maxilla. In this case, it is suspected that the orthodontic treatment may have affected the recurrence of BPOP, because there was no history of trauma.