[Report on clinico-pathological examinations in Meikai University (formerly Josai Dental University) Hospital (4)].

This clinico-pathological study was conducted to examine biopsies and surgical specimens for histopathological diagnosis from April 1983 to March 1988 in Meikai University (formerly Josai Dental University) Hospital. The following statistical results were obtained: 1) The total number of the specimens examined was 2705, 2026 from the dental clinic and 679 from the medical clinic. 2) Concerning age distribution, most specimens from the dental clinic were from patients in the 40's age bracket, whereas most from the medical clinic were from those under 10 years of age. With regard to sex distribution, the difference between males and females was not so much in the dental clinic specimens, but the number from the medical clinic was greater for males than for females. 3) Concerning classification of the tumors from the dental clinic, 181 cases were benign; and of them 41 were odontogenic and 140 were non-odontogenic tumors. Among the odontogenic tumors, ameloblastoma, cementoma, and odontoma were the most numerous. Among non-odontogenic tumors, fibroma was the most common, followed by pleomorphic adenoma. Malignant tumors comprised 77 cases. Of them squamous cell carcinoma was the most commonly found, with the grade-2 type being most numerous. Of the medical clinic tumors, nevus was the most common benign tumor observed; and adenocarcinoma, the most common malignant one. 4) Concerning the distribution of main lesions in the dental clinic specimens, most specimens were cysts or cystic lesions, followed by inflammatory lesions and tumors. Among medical clinic specimens, inflammatory lesions were the most common. 5) Regarding the dental clinic specimens, the most frequently observed case was the radicular cyst (301 samples) among the odontogenic cysts (514 samples); and among non-odontogenic cysts (290 samples), the most common was the mucous cyst (159 samples). 5) In terms of the distribution by location, tissue or organ, most tumors from the dental clinic were from the jaws, followed in descending frequency by those from gingiva and alveolar mucosa, maxillary sinus, lip, buccal mucosa, and tongue. Among the medical clinic tumors, the paranasal cavity and tonsils were the most frequent locations.