BACKGROUND: Odontogenic carcinoma with dentinoid (OCD) is a rare and controversial entity, which has not yet been included in the current World Health Organization classification of odontogenic lesions. Owing to the small number of reported cases, the clinicopathological characteristics, biological behavior, prognosis, and appropriate treatment strategies for OCD remain to be defined. Herein, we present an additional case of OCD with a focus on the differential diagnosis and review of the pertinent literature, in order to enable better recognition by oral clinicians and pathologists and further characterization of this entity.
METHODS: This paper reports a case of OCD in the posterior mandible of a 22-year-old female. Radiography showed a well-defined unilocular radiolucency with radiopaque materials. The intraoperative frozen section pathology gave a non-committed diagnosis of odontogenic neoplasm with uncertain malignant potential. Then a partial mandibulectomy with free iliac crest bone graft and titanium implants was performed. Microscopically, the tumor consisted of sheets, islands, and cords of round to polygonal epithelial cells associated with an abundant dentinoid matrix. Immunohistochemically, the tumor cells were diffusely positive for CK19, p63, and β-catenin (cytoplasmic and nuclear). No rearrangement of the EWSR1 gene was detected. The final diagnosis was OCD. There has been no evidence of recurrence or metastasis for 58 months after surgery. We also provide a literature review of OCD cases, including one case previously reported as ghost cell odontogenic carcinoma from our hospital.
CONCLUSIONS: OCD is a locally aggressive low grade malignancy without apparent metastatic potential. Wide surgical excision with clear margins and long-term period follow-up to identify any possible recurrence or metastases are recommended. Histopathological examination is essential to conclude the diagnosis. Special care must be taken to distinguish OCD from ghost cell odontogenic carcinoma and clear cell odontogenic carcinoma, as misdiagnosis might lead to unnecessary overtreatment. Study of additional cases is required to further characterize the clinicopathological features and clarify the nosologic status and biological behavior of this tumor.

BACKGROUND: Sclerosing odontogenic carcinoma is an exceedingly rare gnathic malignancy first described by Koutlas et al. in 2008, and was only recently designated as a distinct pathologic entity by World Health Organization in the 2017 Classification of Head and Neck Tumors. To date, fewer than fifteen cases of this neoplasm have been reported in the English language literature. This tumor is characterized by thin cords, strands, and small nests of epithelium in a densely sclerotic stroma. In some tumor foci, the density of the stroma may be sufficient to compress the epithelial component beyond detection in the absence of immunohistochemistry, thus rendering this entity a particularly challenging diagnosis in small sample sizes.
METHODS: A 55-year-old male presented with an asymptomatic lesion of posterior left maxilla. Cone beam computed tomography (CBCT) demonstrated a large, well-defined bony lesion with scalloped border, spanning from canine to first molar. External root resorption of the adjacent teeth was also noted. Microscopic examination of the biopsy specimen revealed an odontogenic tumor with features consistent with sclerosing odontogenic carcinoma. Immunohistochemical staining was performed to confirm the diagnosis.
RESULTS: The tumor was positive for CK5/6, CK19, E-cadherin, p63 and negative for CK20 and CK7.
CONCLUSIONS: Sclerosing odontogenic carcinoma is a rare, low-grade malignancy of odontogenic origin, which represents a diagnosis of exclusion in many cases. An immunohistochemical profile demonstrating positivity for markers including CK5/6, CK19, p63, and E-cadherin, in addition to a set of pertinent negative findings, can aid in the diagnosis of this tumor. This entity appears to lack metastatic potential despite its locally destructive behavior and a common histologic finding of perineural invasion.

BACKGROUND: Ghost cell odontogenic carcinoma (GCOC) is a rare malignant odontogenic epithelial tumor with features of benign calcifying odontogenic cysts. Herein, we report two new cases of GCOC and systematically review the previous literature.
METHODS: In case 1, a 46-year-old man complained of painless swelling of the right maxilla for 3 years, with a 1-mo history of hemorrhinia in the right nasal cavity. In case 2, a 72-year-old man was referred to our hospital with a chief complaint of painful swelling of the right mandible. Initially, the preliminary diagnoses were ameloblastomas. Thus, the two patients underwent resection of the tumor under general anesthesia. Finally, immunohistochemical examination confirmed the diagnosis of GCOC. The patient in case 1 was followed for 2 years, with no evidence of recurrence. However, the patient in case 2 was lost to follow-up.
CONCLUSIONS: GCOC is a rare malignant odontogenic epithelial tumor with high recurrence. Local extensive resection is necessary for the definitive treatment of GCOC.

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.

Clear cell odontogenic carcinoma (CCOC) is a rare, odontogenic tumor of the jaws with mandibular involvement usually present in sixth decade of life with female preponderance. It is classified as a malignant tumor of odontogenic origin in 2005 by the World Health Organization because of its aggressive and destructive growth capacity and potential to metastasize. It needs to be distinguished from other primary and metastatic clear cell tumors of the oral and maxillofacial region. Recently, CCOCs have been noted to harbor a Ewing sarcoma breakpoint region 1 gene RNA-binding protein 1 (EWSR1) and activating transcription factor (ATF) gene translocation. To date, cytologic features of only one case have been reported in the literature. We report an additional case of 55-year-old woman with enlarging mass in the left mandible. This report describes cytologic and immunohistochemical features of CCOC with positive EWSR1 gene rearrangements by fluorescence in situ hybridization (FISH). As diagnosis of CCOC is challenging on fine-needle aspiration, immunohistochemistry and FISH analysis are very useful diagnostic tool in clear cell lesions of mandible.

Ameloblastic carcinoma is a rare malignant odontogenic neoplasm that can arise either as a de novo lesion or from pre-existing ameloblastoma. Histopathologically, the tumor retains an ameloblastomatous differentiation pattern but shows cytological features of malignancy. Owing to variable biologic behavior and paucity of long-term follow-up cases, there has been no clear consensus on treatment protocol. The present case of ameloblastic carcinoma arose in the mandible of a 24-year-old male. Surgical treatment involved resection of the mandible along with regional lymph nodes. The patient has been on follow up for the past one year without any recurrence or metastases. An update on ameloblastic carcinoma encompassing the histogenesis, immunohistochemical features and treatment aspects are included.

Ameloblastic carcinoma (AC) is a rare primary odontogenic tumor that has histological features of both ameloblastoma and carcinoma. A total number of 92 case reports speak about its rare incidence, affecting mostly the mandible as a locally destructive lesion. The maxilla is affected even more rarely as only 35 cases have been reported until 2012 in scientific literature. The clinical course of AC is generally aggressive, with extensive local bone destruction. The most common clinical features include swelling, pain, trismus, significant bone resorption with tooth mobility, dysphonia and intraoral fistula. We report two cases of AC with aggressive behavior.