Malignant tumors of the minor salivary glands in northern Pakistan: A clinicopathological study

Abstract

Malignant tumors of the minor salivary glands comprise a small but significant proportion of oral cancers. We analyzed this group of tumors in our population. The records of all cases of malignant minor salivary gland tumors diagnosed at the Armed Forces Institute of Pathology (AFIP), Rawalpindi, Pakistan, during a period of 10 years (1994-2003) are described. The institute receives biopsy material from armed forces and public and private sector hospitals in northern Pakistan as well as referrals for second opinion. A total of 21168 tumors were recorded at the AFIP Tumor Registry during the study period. These included 70 malignant minor salivary gland tumors. Twenty-three of these (32.8%) arose in the palate while the remaining tumors originated at other sites in the oral cavity. The commonest histological type was adenoid cystic carcinoma, constituting 30 cases (42.8%). The next most common type was mucoepidermoid carcinoma comprising 26 (37.1%) cases. The mean age of cases was 43.4 years and the male-to-female ratio was 1:1.4. There were 2 cases each of polymorphous low-grade adenocarcinoma and clear cell adenocarcinoma. The remaining cases included undifferentiated carcinomas, adenocarcinomas (not otherwise specified) and a few other rare tumors. Adenoid cystic carcinoma was the commonest malignant neoplasm of the minor salivary glands followed by mucoepidermoid carcinoma. The palate was the commonest location of these tumors.