ABSTRACT
Salivary gland neoplasms are uncommon, and their epidemiology in Japan has not been well described. We conducted a retrospective review of salivary gland tumors registered in the Hiroshima Tumor Tissue Registry over a period of 39 years. The subjects were 5015 cases ranging in age from 6 to 97 (mean, 54.3) years old. The incidence of both benign tumors and malignant tumors increased with age until 60-69 years and then declined. Among the 5015 salivary gland neoplasms, 3998 (80%) were benign and 1017 (20%) were malignant. Pleomorphic adenoma (PA) was the most frequent benign tumor (68%), followed by Warthin tumor (26%). Adenoid cystic carcinoma (ACC) (27%) and mucoepidermoid carcinoma (MEC) (26%) were the two most frequent malignant tumors. Characteristically, there was a very low incidence of polymorphous adenocarcinoma in Japan. The average annual age-adjusted incidence rate per 100,000 population was 3.3 for benign tumors and 0.8 for malignant tumors. This is the large-scale multi-institutional analysis to describe the characteristics of salivary gland neoplasms, based on the pathological tissue registry data. We hope that the present data can contribute to early diagnosis and effective treatment of salivary gland tumors and to cancer prevention.
ABSTRACT
BACKGROUND: Reported information on the characteristics of benign bone tumors is disjointed, and the long-term trends in the occurrence of malignant bone tumors by histological type have not been reported in Japan. Our aim was to describe the characteristics of both benign and malignant bone tumors as described in cases registered in the Hiroshima Tumor Tissue Registry from 1973 to 2012. METHODS: Cases were identified with the International Classification of Diseases for Oncology (ICD-O-3) topography code C40-C41 (bones, joints, and articular cartilage), and histological types were classified according to the World Health Organization 2013 system. We described the distribution of the cases by behavior, sex, skeletal site of tumor occurrence, histological type, period at diagnosis (in 10-year groups), and age at diagnosis (in 10-year groups). RESULTS: We observed 2,542 benign bone tumors, 272 intermediate bone tumors, and 506 malignant bone tumors. We confirmed that 81.6% of benign bone tumors were chondrogenic, consisting primarily of osteochondromas and enchondromas. Giant cell tumor of bone was the most dominant type of intermediate tumor, whereas osteogenic tumors and chondrogenic tumors were the most dominant types of malignant tumors. Among malignant bone tumors, 41.7% of tumors occurred in the long bones of the lower limb, and there were different peaks of age at the time of diagnosis for osteogenic tumors and chondrogenic tumors. A similar distribution of histological types was seen throughout the 40-year observation period. CONCLUSIONS: Osteochondroma and enchondroma differed in terms of the age of the patient at the time of diagnosis and the skeletal sites where the tumors most frequently occurred. Giant cell tumor had a large impact on occurrence as a common type of intermediate bone tumor. CLINICAL RELEVANCE: The results of the present study, based on pathological tissue registry data, provide knowledge about the epidemiological and pathological features of bone tumors in Japan.
