Challenging diagnosis of a large maxillary lesion: the multi-disciplinary approach.

We report the case of a fit and well pregnant patient in her 20s who presented with a progressively expansile swelling of the left maxilla. Despite extraction of the presumed causative tooth, the lesion continued to enlarge, extending to the orbital floor and resulting in infraorbital nerve paraesthesia. Post-partum radiological imaging demonstrated a markedly displaced upper left third molar associated with a large lytic lesion obliterating the left maxillary sinus. Differential diagnoses included a dentigerous cyst, ameloblastoma or malignancy.Surgical enucleation of the lesion with removal of the ectopic tooth was performed under general anaesthesia. Radiological, histological, microbiological and cytological findings demonstrated overlapping features of dentinogenic ghost cell tumour and calcifying odontogenic cyst (COC). Given the differing biological behaviour and follow-up requirements, multidisciplinary discussion was essential. Multidisciplinary consensus favoured a diagnosis of COC. The patient recovered well and remains under close long-term follow-up.