A 60-year-old man presents with a slowly growing painless lesion confined to the parotid gland. Superficial parotidectomy reveals a 2.0 cm cystic mass. Histologically, this mass is a well-delineated nodule without necrosis or increased mitotic activity. The stroma is fibrotic with mild chronic inflammation but lacks a prominent lymphoid component.
1. True or False: This benign salivary gland tumor occurs exclusively in the parotid gland.
2. True or False: This salivary gland tumor is associated with germline mutations in mismatch repair genes.
Sebaceous Adenoma
This is sebaceous adenoma (SA) of the salivary gland. SA are rare benign tumors usually occurring in the skin but also occasionally reported in salivary gland sites. Salivary SA more commonly involves major salivary glands (particularly the parotid gland), as seen in this case, but can also arise in the oral cavity, either from minor glands or surface mucosa.
Histologically, SA is comprised of closely packed salivary ducts with marked sebaceous and squamous differentiation with nested and cystic growth. There is no evidence of peripheral tissue, perineural or angiolymphatic invasion. High-grade cytomorphologic features, including increased and/or atypical mitotic figures or necrosis, are not present. SA lacks the lymphoid stroma seen in sebaceous lymphadenoma. Salivary SA does not appear to be associated with cutaneous/adnexal SA and there is no known link to Muir-Torre syndrome.
SA of the salivary gland does not recur after complete excision.
Reference
- Skalova A, Hyrcza MD, Mehrotra R, et al. Sebaceous adenoma. In: WHO Classification of Tumours Editorial Board. Head and neck tumours [Internet; beta version ahead of print]. Lyon (France): International Agency for Research on Cancer; 2022 [cited 2024 Jan 1]. (WHO classification of tumours series, 5th ed.; vol. 9). Available from: https://tumourclassification.iarc.who.int/chapters/52/355
Quiz Answers
Q1 = False
Q2 = False
Melad N. Dababneh, MBBS
Head and Neck Pathology Fellow
Cleveland Clinic
Christpher C. Griffith, MD, PhD
Associate Professor of Pathology
Cleveland Clinic Lerner College of Medicine
