Masayuki Kabeya

Prevalence of human papillomavirus in mobile tongue cancer with particular reference to young patients

The carcinogenetic role of human papillomavirus (HPV) in mobile tongue cancer remains unclear because of conflicting results reported in the literature. This disparity is likely to be due to variations in the samples and methods used. Furthermore, despite a tendency for increased prevalence of mobile tongue cancer in young adults, only a few reports specifically in young patients have been published. In the present study on 32 patients, including six in their 20s, we genotyped the prevalence of HPV using a highly sensitive detection tool in fresh‐frozen samples from surgical specimens and a novel detection device with electrochemical DNA chip and loop‐mediated isothermal amplification. In addition, we confirmed HPV prevalence by in situ hybridization and immunohistochemistry for the p16INK4a protein, regarded as a biomarker of HPV‐associated cancers. The frequency of 13 genotypes of high‐risk HPV was 0/32 (0%), which was further confirmed by in situ hybridization. Overexpression of p16INK4a protein was observed in six of the 32 patients (19%), with four (67%) also overexpressing p53. Because there is usually a lack of p53 overexpression in HPV‐associated cancer, it is unlikely that p16INK4a protein overexpression is correlated with HPV infection. Consequently, it is unlikely that HPV infection plays an important role in mobile tongue carcinogenesis, in particular in young adults. In addition, our data suggest that the overexpression of p16INK4a protein is not an appropriate biomarker for HPV association in mobile tongue carcinogenesis. (Cancer Sci 2012; 103: 161–168)

A Case of Ossifying Fibroma of the Maxillary Bone

We report a rare case of ossifying fibroma of the maxillary bone. This patient was a 48-year-old female with pain and swelling on the left root of the nose. CT scan demonstrated a broken appearance of the anterior wall of the maxillary sinus and a ground-glass appearance of the maxillary bone. We performed Caldwell-Luc procedure under general anesthesia to rule out malignant neoplasm. The pathological diagnosis was ossifying fibroma of the maxillary bone. Ossifying fibroma is a benign neoplasm, but classification of this tumor is under discussion. We describe the diagnosis and classification of this tumor with reference to the literature.

A Case of Large Preauricular Epidermoid Cyst Expanded into the Skull Base

The patient was a 73-year-old male, complaining of progressive right otalgia and right facial palsy. A radical mastoidectomy on the right ear was performed, and the histopathological diagnosis was only granulous tissue. A small subcutaneous mass at the right preauricle appeared just after the operation, and an open biopsy was performed. The histopathological diagnosis was epidermoid cyst.MRI showed a high intensity area from the right preauricle to around the medial pterygoid muscle. The symptoms were not improved by the administration of antibiotics and drainage. CT and MRI after about two months revealed that the epidermoid cyst and its infection had expanded from the infratemporal fossa to the pterygopalatine fossa, but they were not detected as an apparent invading lesion of the skull base, so surgical treatment was selected. Although skull base surgery was performed, the cyst and its infection could not be extirpated completely, because they had expanded deeply into the skull base beyond the clivus, against preoperative assessment. Disturbances of the central nervous system appeared and gradually increased. Finally, the patient died of respiratory failure.We treated a rare case of preauricular epidermoid cyst invading the skull base. It was considered that the lesion was possibly more enlarged than was detected in the CT and MRI findings, due to the skull base infection.