A rare case of sebaceous lymphadenoma: Cytohistological correlation of preoperative cytomorphologic findings.

We are presenting a case of a 74-year-old female with a parotid gland mass. Fine-needle aspiration (FNA) of the mass demonstrated cohesive groups of epithelial cells with overall bland-appearing nuclei and abundant vacuolated cytoplasm, consistent with sebaceous cells, in a background of polymorphous lymphocytes, scattered histiocytes, and adipose tissue. Immunostains showed that the epithelial cells stain positive for p63, but negative for CD117 and DOG-1. CD3 and CD20 showed a mixture of T- and B-cells. On the PAP-stained slides, there were numerous sac-like structures, consistent with myospherules. These findings were suggestive of neoplasm with sebaceous differentiation. The main differential diagnosis included sebaceous adenoma, sebaceous lymphadenoma, and other benign lesions with sebaceous differentiation. The parotid mass was resected. Histology sections demonstrated a well-circumscribed neoplasm with multicystic epithelial component and surrounding lymphoid infiltrate, consistent with sebaceous lymphadenoma. Sebaceous lymphadenoma (SLA) is a rare benign salivary gland neoplasm that is most commonly seen in the parotid gland. Preoperative FNA diagnosis of sebaceous neoplasms is challenging. To the best of our knowledge, this is the third case of sebaceous lymphadenoma diagnosed preoperatively. In this manuscript, we detail the epidemiological characteristics and histogenesis of sebaceous salivary gland neoplasms, and the cytomorphologic differential diagnosis of SLA with key diagnostic features of each entity.