Usability of smear cytology prepared for luminal contents combined with histological assessment in odontogenic keratocysts: A technical report of two cases

Histopathological assessments performed via incisional biopsy or enucleation are necessary for the definitive diagnosis of an odontogenic keratocyst (OKC), an intraosseous odontogenic cyst. However, obtaining an adequate and representative sample through an incisional biopsy is often difficult. Moreover, the disappearance of typical morphological characteristics due to secondary inflammation makes histopathology of the enucleated material difficult. Herein, we present two patients with OKCs whose treatment plans entailed the preparation of smears from luminal aspirates and the performance of an incisional biopsy or enucleation. In one patient, typical histological features of OKC were difficult to determine in the broad area; in the other, the indefinite epithelium lining the cyst’s wall encumbered the accurate histological evaluation of paraffin-embedded sections of a preoperative biopsy specimen. During cytological assessments of luminal contents, smear samples of both patients consistently showed numerous anucleate squamous cells, keratinous debris, and isolated keratinocytes without nuclear atypia. The diagnosis of OKC was finally confirmed using operative samples in both cases. Both patients had no postoperative complications. These cases indicate that cytological assessments performed using the smear technique through the aspiration of luminal contents compensate for the weakness of morphological evaluation by incisional biopsy or enucleation.