Low-grade papillary adenocarcinoma of palatal salivary gland origin

The clinicopathologic features of five low-grade papillary adenocarcinomas of palatal salivary gland origin are presented and seven well-documented cases from the literature are reviewed. Patients in our series ranged in age from 30 to 77 years (median 48). Symptoms were nonspecific and related to a mass present for a long duration. Histologically, these were complex cystic, papillary, focally solid tumors that were partially encapsulated. Cytologically, they were composed of bland, predominantly cuboidal cells with eosinophilic or clear cytoplasm. Four tumors were initially considered to be benign mixed tumors, but long-term follow-up indicates that these are slowly growing, malignant neoplasms. Three patients developed solitary cervical lymph node metastases from 2 to 21 years after initial presentation. One tumor underwent an anaplastic transformation to solid adenocarcinoma, and this was from the only patient in our series who died with tumor. Low-grade papillary adenocarcinoma is a clinicopathologically distinctive salivary gland neoplasm, with histologic features unlike those of other papillary salivary gland tumors.