Assistant Professor VCU School of Dentistry Department of Oral & Maxillofacial Pathology Richmond, Virginia
Abstract: An odontogenic keratocyst (OKC) is a benign developmental cyst that originates in the jawbones. These cysts appear radiolucent in the jaw and have a recurrence rate of 19.8%1. Enucleation alone is associated with the highest recurrence rate ranging from 17-56%2. Oral and maxillofacial surgeons can perform either excisional or incisional biopsies to evaluate the lesions. Diagnosis is made based on histopathologic features by an oral and maxillofacial pathologist or less commonly a general pathologist. These lesions classically include uniform parakeratin epithelial cyst lining, but sometimes other features are present. Cysts can be secondarily inflamed, which changes the microscopic appearance. Cysts can also show basal budding and daughter cysts. The aim of this study is to describe the frequency of the other unique histopathology features.
Microscopic slides with an odontogenic keratocyst diagnosis from January 2018- February 2023 from VCU Oral Biopsy Service were identified. No patient health information was collected. Each case was reviewed by a board-certified oral and maxillofacial pathologist for the following findings, inflammation with hyperplastic epithelium, epithelial detachment, focal orthokeratin, daughter cysts, basal budding, cartilaginous metaplasia, dysplasia, Rushton bodies, and cholesterol clefts.
A total of 446 cases were examined. Inflammation with hyperplastic epithelium was the most common feature seen in 281 samples (63.00%). The following features are seen in order of decreasing frequency: epithelial detachment - 235 (52.69%), daughter cysts - 59 ( 13.23%), Rushton bodies - 52 (11.66%), basal budding - 47 (10.54%), cholesterol clefts - 33 (7.39%), focal orthokeratin - 27 (6.05%), cartilaginous metaplasia - 9 (2.02%) and dysplasia - 4 (0.89%).
Inflammation disrupting the epithelial lining and epithelial detachment are the most common in comparison to other features. Rushton bodies and cholesterol clefts are commonly seen with inflammation. Rushton bodies were shown with inflammation disrupting the lining in 50/52 (96.15%) cases. Cholesterol clefts were shown with inflammation disrupting the lining in 29/33 (87.87%) cases. Inflammation causes changes in the epithelial lining including loss of uniform thickness and loss of parakeratin. This can make the diagnosis challenging for a pathologist if the majority of the epithelium is changed by inflammation. Importantly for oral surgeons, the choice of an incisional biopsy in an area of inflammation may disrupt the results. As for the unique and less frequent histopathologic features such as daughter cysts, basal budding, and cartilaginous metaplasia, general pathologists may not be as familiar features due to the field's limited reviews of oral cases. The presence of these unique features may make the diagnosis challenging. Future studies looking at these histopathologic features and clinical behavior would be beneficial, particularly whether the presence of daughter cysts increases the recurrence rate.
1. de Castro MS, Caixeta CA, de Carli ML, Ribeiro JĂșnior NV, Miyazawa M, Pereira AAC, Sperandio FF, Hanemann JAC. Conservative surgical treatments for nonsyndromic odontogenic keratocysts: a systematic review and meta-analysis. Clin Oral Investig. 2018 Jun;22(5):2089-2101. doi: 10.1007/s00784-017-2315-8. Epub 2017 Dec 20. PMID: 29264656.
2. August M, Faquin WC, Troulis MJ, Kaban LB. Dedifferentiation of odontogenic keratocyst epithelium after cyst decompression. J Oral Maxillofac Surg. 2003 Jun;61(6):678-83; discussion 683-4. doi: 10.1053/joms.2003.50137. PMID: 12796876.