Ghost cell odontogenic carcinoma of the maxilla: a case report with a literature review

The aim of this report is to present a rare case of a Ghost cell odontogenic carcinoma (GCOC) of a 21-year-old man with review of the literature. The patient was treated surgically, and one of the surgical margins was involved, the patient received adjuvant radiotherapy for local control. Five months later, patient presented with infraorbital lesion which was proven histological to be GCOC. Radiological images, histological sections and clinical photographs are also presented. One year after the second surgery, the patient was tumor free. The only effective treatment modality was surgical removal.


Introduction
Ghost cell odontogenic carcinoma (GCOC) is extremely rare with only 30 case reports in the English literature [1]. This disease has unpredictable biological behavior [2] which may arise de novo or from preexisting calcifying cystic odontogenic tumor (CCOT) [3].
GCOC was so called because of the presence of keratinized ghost cells in association with ameloblastomatous epithelial component and a CCOT with frank malignant counterpart. In general odontogenic tumors are rare neoplasms when compared to nonodontogenic tumors in the oral cavity. According to Adebayo et al [4], the odontogenic neoplasms represent (32%) of tumors and tumor-like lesions of the oral and perioral structures. Of these, malignant odontogenic carcinomas represent 1%.

Patient and observation
A 21 year old male non tobacco user with a history of surgical removal of a small mass started after tooth extraction. The swelling reappeared again, and the patient was referred from a peripheral

Discussion
GCOC is an uncommon neoplasm and was first described in 1985 as well documented case report by Ikumra et al [5]. It is considered as malignant variant of odontogenic ghost cell tumor (OGCT) or calcified odontogenic cyst (COC) [6].
As the term "Ghost cell odontogenic carcinoma" underlines, Odontogenic because of ameloblast like cell, Ghost "due to the presence of shadows of keratinized epithelial cells with wet keratin".
Various names were applied to this tumor including malignant COC, Ghost cell odontogenic carcinoma, aggressive epithelial ghost cell odontogenic tumor, dentinogenic ghost cell ameloblastoma, carcinoma arising in a COC, and malignant calcifying ghost cell odontogenic tumor [6].
It is more common in males with an age peak at the fourth decade of life (2). Most of GCOC occurred within the maxilla. Clinical Page number not for citation purposes 3 presentation varies with painful swelling and paresthesia being the most common complaint. Facial swelling is also common finding [7].
The geographical distribution of GCOC is prominent in Asia and was attributed to the fact that COC is more common in Asian and the GCOC may arise from the lining of the cyst or malignant transformation of benign tumor [8]. Radiologically, the lesion most commonly seen as a mixed radiolucency and radiopacity with ill defined margins and tooth displacement or root resorption although impacted tooth was reported [9]. Histologically, the tumors that are The treatment of choice is surgical excision with safety margins [8].
The issue of using chemo or radiotherapy is not clear due to rarity of this tumor. However, in the present case, the radiotherapy was not effective. The 5 year survival rate was estimated to be 73%, and the recurrence is common [9]. Therefore, periodic follow up is crucial.

Conclusion
Ghost cell odontogenic carcinoma is a very rare variant of odontogenic carcinoma. It has an aggressive course of growth in bone. Unlike oral squamous cell carcinoma, the radiotherapy has no role in the treatment of this case and the only effective treatment modality was surgery. This reflects the importance of obtaining clear surgical margins in surgical excision.

Competing interests
The authors declare no competing interests.