Keratocystoma of the Parotid Gland: A Systematic Review of Clinicopathologic Characteristics

Keratocystoma is a rare benign neoplasm of the parotid gland, histologically characterized by multicystic keratinizing stratified squamous epithelium. Due to its resemblance to squamous malignancies, it represents a diagnostic challenge. This systematic review aims to summarize all published cases of parotid gland keratocystoma and to integrate one newly identified case in order to define its clinicopathologic features and clinical outcomes.

A systematic literature search of PubMed and Google Scholar was conducted without date restrictions in accordance with PRISMA 2020 guidelines. The protocol was registered in PROSPERO (CRD420251024191). Peer-reviewed case reports and case series of histopathologically confirmed keratocystoma limited to the parotid gland were included. Demographic, clinical, radiologic, histopathologic, immunohistochemical, therapeutic, and follow-up data were extracted and descriptively analyzed. Methodological quality was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklists. One additional institutional case treated at Hannover Medical School in March 2025 was included.

Fifteen patients (14 from the literature and one new case) were identified. The mean age was 36.9 years (range: 1-77 years) with a slight male predominance. All tumors presented as painless parotid swellings and were treated surgically, most commonly by partial or lateral parotidectomy. No recurrences were reported during a mean follow-up of 22.8 months. Histologically, all cases demonstrated consistent squamous epithelial features with immunohistochemical positivity for AE1/AE3, CK5/14, and p63. The newly reported case represents the oldest patient described to date.

Keratocystoma of the parotid gland exhibits reproducible benign clinical behavior and characteristic histopathologic features. Surgical excision appears curative, supporting its classification as a distinct benign salivary gland neoplasm that should be considered in the differential diagnosis of cystic parotid lesions.