Kanji Komaki

Elucidating risk factors for oral leukoplakia affecting gingivae in Japanese subjects

Background: Clinicopathological studies have revealed some distinct anatomical variations in the clinical presentation of oral leukoplakia (OL). Screening studies have shown that gingival leukoplakia (GL) to be more common among the Japanese. Objective: A hospital-based case-control study was undertaken among patients diagnosed with OL to compare clinico-pathological data between GL and OL affecting other sites (n-GL). Methods: One hundred fifty-one subjects attending four city hospitals in Japan diagnosed with OL were recruited to this study. OL was diagnosed by World Health Organization criteria. They were interviewed for risk factors, clinical presentations were charted and investigated by patch testing for allergy to dental materials and by biopsy for dysplasia. Results: Eighty-eight with GL and 63 with n-GL were included in the study. GL lesions were predominantly white (93%) though n-GL leukoplakia had red (speckled) foci in 26%. Eighty percent of GL were seen in association with prosthesis or restorations. There were no significant differences by age or in tobacco and alcohol use in the two groups. Metal allergy test was positive in 58% of the GL but was not significantly higher compared to the n-GL (41%). Histopathological features showed that inflammatory cell infiltrate was predominant in n-GL group (p = 0.021). Higher dysplasia grades were also found in n-GL (p = 0.018). During follow-up, nine oral cancers (14%) were detected in n-GL group and among GL cases four developed oral carcinomas (5%) (p = 0.043). Cox hazard regression analysis revealed that after adjusting for age and sex, GL group was found to have a lower malignant risk, with a hazard ratio of 0.89 (95% CI: 0.51–1.04) when compared to n-GL. Conclusions: GL was more benign compared to n-GL in Japanese subjects, though risk factors appear similar. Further study is warranted to ascertain whether trauma may play an important role for hyperkeratinization of gingival tissues and possible evolution of GL to proliferative verrucous leukoplakia in later years.

Ectopic oral tonsillar tissue: a case series with bilateral and solitary presentations and a review of the literature.

An ectopic tonsil is defined as tonsillar tissue that develops in areas outside of the four major tonsil groups: the palatine, lingual, pharyngeal, and tubal tonsils. The occurrence of tonsillar tissue in the oral cavity in ectopic locations, its prevalence, and its developmental mechanisms that belong to its formation remain unclear. In this report, we describe a rare case of bilateral symmetric ectopic oral tonsillar tissue located at the ventral surface of the tongue along with two solitary cases arising from the floor of the mouth. The role of immune system and its aberrant response leading to ectopic deposits desires further studies. As an ectopic tonsil may simulate a benign soft tissue tumor, this case series highlights the importance of this entity in our clinical differential diagnosis of oral soft tissue masses.