Background and aim: Lichen planus (LP) is a chronic inflammatory disease with an uncertain pathogenicity. Recent reports have revealed that angiogenesis is effective in the pathogenesis and biologic behavior of lesions. Considering the limitations of the studies related to angiogenesis in oral LP (OLP) and the controversial results, the present study aimed to compare the expression of vascular endothelial growth factor (VEGF) in OLP and normal mucosa. Materials and methods: In this case-control study, 4-µm sections were prepared from selected OLP (erosive type) blocks and normal mucosa samples for immunohistochemistry (IHC) staining with VEGF marker. VEGF expression was quantitatively assessed via counting the positive-stained cells. The mean percentages of positivestained cells in each sample were categorized in three groups: score 0 (the presence of 10% or lower), score 1 (the presence of 10% to 50%), and score 2 (the presence of more than 50% of stained cells). T-test and Mann-U-Whitney test were used for statistical analyses. Results: The mean percentage of VEGF expression was 39.8% in 35 OLP samples, and 20.5% in 20 normal mucosa samples. Twenty OLP samples (57%) had score 1, and 15 (43%) had score 2. Eighteen normal mucosa samples (90%) had score 1, and two (10%) had score 2. Also, score 0 was not reported in any of the samples. The percentages of VEGF expression in OLP and normal mucosa did not show any statistically significant differences (P=0.5). However, there was a significant difference between OLP and normal mucosa in VEGF expression score (P=0.012), and OLP samples had significantly higher scores. Conclusion: According to the results, VEGF expression in erosive OLP samples was significantly higher than that in normal mucosa.

Calcifying cystic odontogenic tumor (CCOT) demonstrates considerable diversity in histopathology and clinical behavior. Ghost cell odontogenic carcinoma (GCOC) is the rare malignant counterpart of CCOT and it frequently arises from malignant transformation of a recurrent CCOT. In this paper, we present a case of CCOT and discuss its distinct histopathologic features in recurrence. Then, we will have a review on clinical, histopathological, and immunohistochemical aspects of GCOC in the literature. Predictive factors of malignant transformation in a benign CCOT will also be discussed.

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Epithelial-myoepithelial carcinoma (EMC) is considered as a rare malignant salivary gland neoplasm with good prognosis, low recurrence rate and rare metastasis. Here we present a case of epithelial-myoepithelial carcinoma in a 42-year-old female with a swelling of 3-year duration in her palate. Histopathologic evaluation of the lesion demonstrated a wellcircumscribed, biphasic salivary gland tumor composed of double-layered ductal/glandular structures, composed of small luminal eosinophilic cells and abluminal larger clear myoepithelial cells, and luminal cells were positive for pan-cytokeratin, while the abluminal cells exhibited strong immunoreactivity for p63. Ki-67 proliferative index was 1% in abluminal cells. In this article, histopathologic and immunohistochemical features of EMC and its mimics are discussed and the previously reported cases of EMC in the literature are summarized.