Fine-needle aspiration cytomorphology of sebaceous lymphadenoma of the salivary gland

Sebaceous lymphadenoma (SLA) is a histologic variant of lymphadenoma or sebaceous adenoma of the salivary gland. The fine-needle aspiration (FNA) cytology of SLA has not been well-described. In this report, we reported a case that involved an 81-year-old male with a long-standing left parotid mass and was diagnosed on FNA cytology. The FNA smears showed clusters of three types of epithelial cells in a background of abundant lymphoid cells, macrophages and abundant proteinaceous materials. The predominant epithelial cells were large polygonal cells with abundant cytoplasm filled with multiple, uniform, small, and clear vacuoles, ill-defined cytoplasmic borders, and small centrally located round nuclei with finely granular chromatin, conspicuous nucleoli and indented nuclear membranes apparently imprinted by cytoplasmic vacuoles. These cells were surrounded by polygonal or flat cells with less or more dense cytoplasm, indistinct cell borders and round or oval small nuclei with smooth nuclear membranes, which correspond to germinative or basaloid cells. Some cells had granular cytoplasm. Large three dimensional clusters of nonkeratinized squamous cells have oval nuclei containing evenly distributed chromatin, and scant to moderate dense cytoplasm that were arranged in a "stream of fish" pattern. Rare granulomas and cystic contents (degenerated cells, inflammatory cells, macrophages, and abundant granular debris/proteinaceous material) were also seen. The diagnosis of SLA was confirmed by the surgical resection.