SATB2 and MDM2 Immunoexpression and Diagnostic Role in Primary Osteosarcomas of the Jaw.

Primary osteosarcomas of the jaw (OSJ) are rare, accounting for 6% of all osteosarcomas. This study aims to determine the value of SATB2 and MDM2 immunohistochemistry (IHC) in differentiating OSJ from other jawbone mimickers, such as benign fibro-osseous lesions (BFOLs) of the jaw or Ewing sarcoma of the jaw. Certain subsets of osteosarcoma harbor a supernumerary ring and/or giant marker chromosomes with amplification of the 12q13-15 region, including the murine double-minute type 2 (MDM2) and cyclin-dependent kinase 4 (CDK4) genes. Special AT-rich sequence-binding protein 2 (SATB2) is an immunophenotypic marker for osteoblastic differentiation. Cases of OSJ, BFOLs (ossifying fibroma and fibrous dysplasia) of the jaw, and Ewing sarcoma of the jaw were retrieved from the Departments of Oral Pathology and Oral Medicine, Faculty of Dentistry, Obafemi Awolowo University and Lagos State University College of Medicine, Nigeria. All OSJ retrieved showed histologic features of high-grade osteosarcoma. IHC for SATB2 (clone EP281) and MDM2 (clone IF2), as well as fluorescence in situ hybridization (FISH) for MDM2 amplification, were performed on all cases. SATB2 was expressed in a strong intensity and diffuse staining pattern in all cases (11 OSJ, including a small-cell variant, 7 ossifying fibromas, and 5 fibrous dysplasias) except in Ewing sarcoma, where it was negative in neoplastic cells. MDM2 was expressed in a weak to moderate intensity and scattered focal to limited diffuse staining pattern in 27% (3/11) of cases of OSJ and negative in all BFOLs and the Ewing sarcoma. MDM2 amplification was negative by FISH in interpretable cases. In conclusion, the three cases of high-grade OSJs that expressed MDM2 may have undergone transformation from a low-grade osteosarcoma (LGOS). SATB2 is not a dependable diagnostic marker to differentiate OSJ from BFOLs of the jaw; however, it could serve as a valuable diagnostic marker in differentiating the small-cell variant of OSJ from Ewing sarcoma of the jaw, while MDM2 may be a useful diagnostic marker in differentiating OSJ from BFOLs of the jaw, especially in the case of an LGOS or high-grade transformed osteosarcoma.

BRAF V600E mutation-specific immunohistochemical analysis in ameloblastomas: a 44-patient cohort study from a single institution.

PURPOSE: The aim of this study is to investigate the presence and prevalence of BRAF V600E mutation in ameloblastomas using anti-BRAF V600E monoclonal antibody (VE1 clone) and to identify any clinicopathologic correlation with BRAF V600E mutation in ameloblastoma. MATERIALS AND METHODS: The pathology files of the Department of Oral Pathology and Oral Medicine, Faculty of Dentistry, Lagos State University College of Medicine, Lagos, Nigeria, were searched for the diagnosis of ameloblastoma from 2016 to 2020. Archived non-decalcified formalin-fixed paraffin-embedded tissue underwent immunohistochemistry using anti-BRAF V600E antibody at the University of Pittsburgh, Pennsylvania. Clinicopathologic data such as age at diagnosis, gender, jaw bone involved (mandible or maxilla), tumor location (anterior or posterior) and histologic subtype were collected. The clinicopathologic parameters were analyzed using Chi-square test and Fisher's exact test according to the BRAF status. RESULTS: Forty-four cases of ameloblastoma were retrieved. The male to female ratio was 1.32:1. The average age of patients at diagnosis was 33.3 years. Thirty-nine cases were located in the mandible and 5 cases in the maxilla. Only cases in the mandible were positive for anti-BRAF V600E antibody (n = 15/39; 38.5%). There was a significant correlation between BRAF V600E expression in mandibular tumors and histologic subtype (p = 0.02); however, no significance was observed for gender, age and tumor location. CONCLUSION: BRAF V600E mutation preferentially occurs in mandibular ameloblastomas, especially in non-plexiform ameloblastomas. These patients may benefit therapeutically from the use of BRAF inhibitors.

Clear cell variant of squamous cell carcinoma of skin: A report of a case.

Clear cell squamous cell carcinoma (SCC) is a rare variant of SCC of skin in which ultraviolet radiation has been suggested as possible etiology. This case is that of a 62-year-old male concrete block maker/bricklayer who presented with a 6 months history of a non-healing ulcer on the left side of his face. Histology showed features of malignant epithelial neoplasm composed of islands of large oval to polyhedral malignant squamous cells with eosinophilic to amphophilic cytoplasm and vesicular nuclei and there were areas showing clear cell differentiation and isolated areas of keratin pearl formation. The lesion was also negative for periodic acid schiff, mucicarmine, and alcian blue stains but was strongly positive for AE1/AE3 (immuno-stain). This case showed an aggressive and bizarre clinical presentation but more report of cases are needed to have a better characterization of the clinical presentation and prognosis of this variant of SCC.

A review of 413 salivary gland tumours in the head and neck region.

OBJECTIVES: Salivary gland tumours (SGTs) are a group of heterogeneous lesions with complex clinico-pathological characteristics and distinct biological behaviours. Previous studies have reported geographic variations in site distribution, incidence and histological types of SGTs. The aim of this study was to describe the demography of SGTs seen at a tertiary health centre and compare findings with previous studies. STUDY DESIGN: Data on SGTs from archives of the Department of Oral Pathology and the Department of Pathology, University College Hospital Ibadan were retrieved. Information about histological types, age, sex and location were analyzed using SPSS for Window (version 20.0; SPSS Inc. Chicago, IL). Reactive and tumor-like lesions such as sialometaplasia, benign lymphoepithelial lesion, lymphoepithelial cyst, mucocele, mucous extravasation phenomenon, ranula, and sialosis were excluded from the study. RESULTS: 413 SGTs consisting of 221 (53.5%) malignant and 192 (46.5%) benign lesions were seen. SGTs occurred more in females (50.6%) than males (49.4%) with a mean age of 43.7 (±16.9) years and peak age in the fifth decade of life. The parotid with 171 (41.4%) cases was the commonest site, followed by palate with 89 (21.5%) cases, while only 7(1.7%) cases were seen in sublingual gland. Pleomorphic adenoma with 169 (40.9%) was the most frequent SGT followed by adenoid cystic carcinoma with 93 (22.5%) cases which also was the most frequent malignant SGT while only 3 (0.7%) cases of Warthin's tumour were seen. CONCLUSION: This report is one of few that showed a higher occurrence of malignant SGTs compared to their benign counterparts. The findings were essentially similar to findings in Africa but showed SGTs to be more common in females. The reason(s) for high occurrence of malignant SGTs in minor salivary glands and the rarity of Warthins tumour in this study and other African series compared to those from America needs further investigation. Key words:Salivary gland tumours, parotid gland, pleomorphic adenoma, adenoid cystic carcinoma, warthin's tumour.