Tumor immune microenvironment in odontogenic carcinomas: Evaluation of the therapeutic potential of immune checkpoint blockade

BACKGROUND

Despite recent advances in the use of immune checkpoint blockade (ICB) across various cancer types, its efficacy in odontogenic carcinomas remains unexplored. This study aims to investigate PD-L1 expression and the tumor immune microenvironment (TIME) in odontogenic carcinomas to determine the therapeutic potential of ICB and the significance of immune markers.

METHODS

The expressions of PD-L1 and T cell markers (CD3, CD8, and FOXP3) were visualized by immunohistochemistry in 21 tissue samples of odontogenic carcinomas. Tumoral PD-L1 expression and the density and spatial distribution of T cell subsets were evaluated, from which TIME was determined. The associations of the variables with clinicopathological and prognostic factors were statistically analyzed.

RESULTS

PD-L1 was positively expressed in 52.4% (11/21) of the cases studied. Among tumor types, ameloblastic carcinoma showed significantly higher PD-L1 expression (p = 0.016). TIME based on the intratumoral and stromal T cell distribution was immune-inflamed in 61.9% (13/21) and immune-excluded in 38.1% (8/21), with no immune-desert cases. PD-L1 expression was associated with the densities of all intratumoral T cell subsets (p = 0.03 for CD3, p = 0.03 for CD8, and p = 0.008 for FOXP3) but not with those of stromal T cells. High PD-L1 expression was associated with larger tumor size (p = 0.021), while the intratumoral CD8/CD3 ratio was inversely correlated with tumor size (p = 0.048).

CONCLUSION

These findings indicate the involvement of adaptive immune resistance in a subset of odontogenic carcinomas and support the therapeutic potential of ICB in patients with these rare malignancies.

Case report: Ghost cell odontogenic carcinoma in a dog: diagnostics and surgical outcome

A 6 year-old spayed female Poodle presented with a mandibular mass. Radiographic examination revealed osteolysis from the right mandibular canine to the fourth premolar, along with horizontal bone loss and dorsal displacement of the right mandibular first and second premolars. Skull cone beam computed tomography revealed osteolysis at the level of the right mandibular canine and fourth premolar. A destructive bone lesion was observed in the apical area of the right mandibular canine, with mass invasion of the interradicular bone of the right mandibular first molar near the mandibular canal. Consequently, unilateral total mandibulectomy and skin flap surgery were performed. Histopathological examination revealed poorly demarcated and infiltrative neoplastic epithelial cells that formed small islands and trabeculae. Neoplastic cells exhibited the malignant features of cytological atypia and high mitotic activity. Furthermore, the neoplastic epithelial cells frequently showed ghost cell changes and were diagnosed as ghost cell odontogenic carcinoma (GCOC). The dog was followed up for 1 year, during which no severe complications or local recurrence was observed, except for slight mandibular drift, tongue protrusion, and drooling. This case report describes the clinical features, diagnostic imaging, and histologic features of an unreported GCOC in a dog and the favorable outcome following surgical resection.

Ameloblastic carcinoma: A rare case with diagnostic dilemma

Ameloblastic Carcinoma is a rare malignant Odontogenic tumour with characteristic histopathology and clinical features which requires aggressive surgical treatment and surveillance and therefore differs from ameloblastoma. It is possible that ameloblastoma shows a variety of histologic and biologic behaviour ranging from benign to frank malignancy. Cases of ameloblastoma should thus be studied carefully, correlating their histologic pattern with biologic behaviour to direct subtle changes in histology that may predict the aggressiveness of the tumor. Thus the identifying features of Ameloblastic Carcinoma must be carefully known and recognized by dental professionals. The purpose of this article is to report a rare case of Ameloblastic Carcinoma and to highlight the clinical, radiological and variable histological features with possible differential diagnosis.

Clear cell odontogenic carcinoma of mandible: An unclarified entity

Morphological tampering of cellular architecture is a frequent phenomenon, leading to a spectrum of histological melange at light microscopic level. One such group of tumors which exhibit diagnostic and therapeutic dilemmas are the Clear cell tumors. Clear Cell Odontogenic Carcinoma (CCOC) is an infrequent tumor, which is aggressive by nature among the odontogenic tumors. A case of CCOC of mandible in a denture wearer is presented with the emphasis on diagnostic work up and clarified and unclarified facts of the tumor.

Cytomorphology and immunohistochemistry of a recurrent clear cell odontogenic carcinoma with molecular analysis: A case report with review of literature

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.

Malignant odontogenic tumors: an update on selected tumors

This is an update on selected odontogenic malignancies. The article deals with aspects of recognized odontogenic carcinomas, odontogenic sarcoma and a yet unrecognized entity, sclerosing odontogenic carcinoma. Odontogenic malignancies are exceedingly rare, complicating a thorough understanding of the biologic behavior, reproducible standardized diagnostic criteria, appropriate classification and clinical management. Without the knowledge of the tumor's biologic behavior, adequate clinical management is difficult and patient outcomes uncertain. The histopathologic features are emphasized as well as the more recent biomarker findings. These recent advances may facilitate further understanding of this group of malignancies and provide useful stratification to guide patient management.

Ameloblastic carcinoma of the mandible: Report of a case and review

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: A clinicopathologic dilemma - Report of two cases with total review of literature from 1984 to 2012

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.

Spindle cell variant of ameloblastic carcinoma arising from an unicystic amelobastoma: Report of a rare case

Malignant transformation of ameloblastomas arising from an odontogenic cyst or de novo is well-recognized. Malignancies in ameloblastomas may involve metastasis or a local dysplastic change in the tissue. The latter are classified as ameloblastic carcinomas. A 75-year-old male presented with a mandibular cystic swelling, with no evidence of metastasis. Dysplastic ameloblastic cells with spindle-cell transformation were seen arising from a cystic lining with features of a unicystic ameloblastoma. Immunohistochemically the lesion stained positive with cytokeratin 8,19 and alpha smooth muscle actin, but was negative for vimentin. A diagnosis of spindle-cell ameloblastic carcinoma was made. Spindle-cell ameloblastic carcinomas are rare and this is the second case arising from a unicystic ameloblastoma reported in literature. The recognition of this transformation and inclusion of this entity in the classification of ameloblastic carcinomas is stressed.