Search

Objective Myopericytoma (MP) is a rare soft tissue neoplasm infrequently arising in the oral cavity. We aimed to clarify the clinicopathologic characteristics of oral MP based on histologic and immunohistochemical findings. Methods We reviewed myogenic neoplasms in our archives and selected 6 cases of MP. Immunostainings were performed using antibodies for smooth muscle actin (SMA), calponin, h-Caldesmon, muscle-specific actin (MSA), desmin, and type IV collagen antibody. Results Our patients were predominantly female, and the mean age and size were 57.5 years and 10.8 mm, respectively. Histologically, 3 of 6 cases were well circumscribed but others showed ill-defined borders. Three cases were classic but others were angioleiomatous and myofibromatous cases with a mostly fascicular pattern. Myxoid change appeared in 2 cases. Hyalinized nodules (vascular balls) were found in both classic and nonclassic types. Only one case partially comprised small round cells mimicking glomus cells, but these lacked peculiar type IV collagen expression. Two angioleiomatous cases harbored dilated blood vessels. Two cases partially showed a staghorn and indistinct biphasic pattern but a myofibromatous type demonstrated neither. Immunohistochemically, all cases that tested were positive or focally positive for SMA, MSA, and calponin but negative tumor cells were noted in part. However, h-Caldesmon was only detected in 2 out of 5 cases examined. Desmin was constant-negative except for 1 classic case with focally positive reaction. Conclusion Oral MPs are morphologically and phenotypically heterogeneous neoplasms that can sometimes mimic angioleiomyoma or glomangioma. It is necessary to recognize the presence of cases showing varied myogenic natures.

Perforation of floor of the dental pulp is often encountered during root canal treatment in routine clinical practice of dental caries. If perforation were large, granulation tissue would grow to form periodontal polyp. Granulation tissue consists of proliferating cells however their origin is not clear. It was shown that the cells in granulation tissue are mainly from migration of undifferentiated mesenchymal cells of the bone marrow. Hence, this study utilized GFP bone marrow transplantation mouse model. The floor of the pulp chamber in maxillary first molar was perforated using ½ dental round bur. Morphological assessment was carried out by micro CT and microscopy and GFP cell mechanism was further assessed by immunohistochemistry using double fluorescent staining with GFP-S100A4; GFP-Runx2 and GFP-CD31. Results of micro CT revealed alveolar bone resorption and widening of periodontal ligament. Histopathological examination showed proliferation of fibroblasts with some round cells and blood vessels in the granulation tissue. At 2 weeks, the outermost layer of the granulation tissue was lined by squamous cells with distinct intercellular bridges. At 4 weeks, the granulation tissue became larger than the perforation and the outermost layer was lined by relatively typical stratified squamous epithelium. Double immunofluorescent staining of GFP and Runx2 revealed that both proteins were expressed in spindle-shaped cells. Double immunofluorescent staining of GFP and CD31 revealed that both proteins were expressed in vascular endothelial cells in morphologically distinct vessels. The results suggest that fibroblasts, periodontal ligament fibroblasts and blood vessels in granulation tissue were derived from transplanted-bone marrow cells. Thus, essential growth of granulation tissue in periodontal polyp was caused by the migration of undifferentiated mesenchymal cells derived from bone marrow, which differentiated into fibroblasts and later on differentiated into other cells in response to injury., 2016

The expression of Notch in 30 cases of pleomorphic adenoma was examined by immunohistochemistry.Comparing the results of our study with previous literatures, from the partial CK7 expression and substantial Notch expression in ductal epithelial cells as well as the Notch expression in solid tumor nests, it can be inferred that Notch is involved in cell differentiation. CK13 expression was observed in cells undergoing squamous metaplasia and Notch expression was seen in the nucleus of basal and squamous cells. The intense Notch expression in basal cells and weak expression in squamous cells suggests that Notch is involved in the differentiation from basal to squamous cell. Moreover, the loss of nuclear expression on the inner layer would signify that differentiation is about to end or has been terminated. Notch was expressed in the cytoplasm of cartilage cells and in the cell membrane of mucous cells but not in the nucleus indicating that differentiation has been concluded. Notch involvement is suspected in cell differentiation in areas showing ductal structures and squamous metaplasia. In summary, Notch is involved in cell differentiation of ductal cells in PA. Nuclear expression was shown in tumor cells in solid nests and surrounding structures. Moreover, Notch is expressed by basal cells undergoing squamous metaplasia suggesting the participation of Notch in cell differentiation in PA., 2015

The expression of HSP27 and some CKs were examined the 40 cases of typical solid/multicystic ameloblastoma using immunohistochemical techniques. In order to examine the relevance of HSP in cell differentiation, we focused on the cytoskeletal expression of CK. CK19 is a marker of typical odontogenic epithelium widely observed in follicular and plexiform types of ameloblastomas. Since staining with CK14 is one of the measures of the differentiation potential of squamous cells and is extensively expressed in both follicular and plexiform types, it implies that squamous differentiation of each type can occur. CK8 was strongly detected in tumor nests in plexiform type but weakly detected in follicular type. It was considered that the expression of HSP27 in plexiform type correlated with the expression of CK8 suggesting that HSP27 might have regulated the expression of CK8., 2013