Multiple Calcifying Odontogenic Cysts Involving the Maxillary Sinus

Introduction: Calcifying odontogenic cyst (COC) is an uncommon odontogenic lesion, classified in two variants: the cystic variant and neoplastic (solid) variant. Case Presentation: This case report presents multiple COC, which involved the maxillary bone and sinus in a ۳۰-year-old man. Several of these lesions were cystic, while the others were neoplastic in type, and the lesions were removed surgically. Discussion: Based on a literature review available on this topic in English, our case study was found to be the first one with multiple COC, showing both the cystic and neoplastic histopathological variant. Considering the high rate of recurrence of neoplastic COC, the patients should benefit from a long follow-up after treatment.