Signet-ring cell (mucin-producing) adenocarcinomas of minor salivary glands.

We report seven cases of minor salivary gland carcinomas characterized by the marked presence of mucin-containing signet-ring cells. These tumors were distinctive in their microscopic appearance and displayed features not seen in any other type of salivary gland malignancy. They typically exhibited invasive growth by narrow parallel strands, randomly scattered small nests, or individually infiltrating cells. Solid, cribriform, or targetoid areas were absent, as well as papillary components. Ductal differentiation was minimal, and seen in only four cases. Degrees of cellularity varied from one area to another. The tumors were cytologically bland. We think that these tumors represent a unique subset of intraoral minor salivary gland carcinomas.