Odontogenic Myxoma: A 23-Year Retrospective Series of 38 Cases

Odontogenic myxoma (OM) is an uncommon benign odontogenic tumor arising in the jaw. Though it has slight histologic overlap with other entities, definitive diagnosis is imperative considering the tumor's aggressive nature, high recurrence rate, and necessity of radical surgical intervention in large-sized lesions. With IRB approval, a retrospective search of the University of Florida College of Dentistry Oral Pathology Biopsy Service archives from 1994 to 2017 for diagnosis of OM of the jaw was performed. Biopsy reports and original slides for each case were assessed and reviewed along with any accompanying radiographs to confirm the diagnosis. Immunohistochemical staining was utilized to exclude entities with histologic overlaps, such as intraosseous myxoid neurofibroma. A total of 38 cases were included. The patients' age ranged from 6 to 84 years, with a mean age of 37.47 years. Females comprised two-thirds of the cases (n = 25) versus males (n = 13). The mandible was the most affected at 60.5% (n = 23), followed by maxilla 39.4% (n = 15). Posterior jaw involvement was higher than anterior in both the mandible (n = 20 versus n = 3) and the maxilla (n = 11 versus n = 4). Most lesions presented clinically as expansile masses with variable radiographic appearance. The clinical impression from submitting providers included "gelatinous masses", abscesses, odontogenic lesions, fibro-osseous lesions, soft tissue or bone neoplasms, and reactive gingival lesions. A consensus of odontogenic myxoma as a diagnosis was rendered for 30 cases (79%), while in 8 cases (21%) that exhibited a more fibrous stroma was identified as fibromyxoma. OM may exhibit a varied demographic and clinical profile with a wide spectrum of histologic presentations. Pathologists should be sentient of this variability in order to arrive at an accurate diagnosis and correctly manage these patients.