Histopathological and Immunohistochemical Study of Peri-Implant Epithelium

Background: Human beta-defensins (HBDs), epithelial-derived antimicrobial peptides, contribute to gingival health and periodontal disease. Particularly, the upregulation of HBD-3 expression in periodontal tissues is described to contribute to periodontal tissue regeneration. Specifically, the upregulation of HBD-3 expression in periodontal tissues is described to contribute to periodontal tissue regeneration. But there has been insufficient investigation of the inner epithelium in peri-implantitis, especially the HBD expression patterns as protection against oral infection. Objectives: The purpose of this study was to investigate the histopathological characteristics of the inner implant epithelium in peri-implantitis using histopathological and immunohistochemical methods and to compare it with the inner marginal epithelium in periodontitis. Materials and Methods: The biopsied cases consisted of 10 peri-implantitis, 11 periodontitis, and 10 controls. HE observation, measurement of the thickness of the inner epithelium, and immunohistochemical analysis for Ki-67 and HBD-3 were conducted. Results: Concerning the thickness of the inner epithelium, it was significantly higher in periodontitis (156.2 [138.0, 186.4] μm) than in peri-implantitis and control, 70.7 [67.5, 97.5] μm and 80.7 [76.6, 89.4] μm, respectively (p Conclusion: Decreased production of HBD-3 in keratinocytes composing the inner implant epithelium may be one of the factors affecting tissue repair in peri-implantitis.

Comparative Cytological and Histopathological Study of Peri-Implantitis and Periodontitis

Peri-implant diseases, such as peri-implant mucositis and peri-implantitis, pose significant challenges to the long-term prognosis of dental implants. This study aimed to comprehensively compare peri-implantitis with periodontitis from cytological and histopathological perspectives, shedding light on the morphological characteristics associated with peri-implantitis. Thirteen patients, including six with peri-implantitis and seven with periodontitis, were included in the study. Cytological examination of affected gingival mucosa revealed distinct differences between the two conditions. Peri-implantitis exhibited an inflammatory background predominantly composed of neutrophils with lobulated nuclei, accompanied by stratified squamous epithelial cells showing signs of keratinization. In contrast, periodontitis showed a similar neutrophilic inflammatory background but with non-keratinized epithelial cells. Histopathological examination further confirmed these differences, with peri-implantitis showing keratinized epithelium in the inner epithelial layer. This histological finding aligns with the notion that peri-implantitis has a distinct mucosal profile compared to periodontitis. Additionally, cytological analysis revealed that peri-implantitis had a lower occurrence rate of Light green-positive cells, indicating a tendency toward keratinization. This finding suggests that the presence of keratinized mucosa might be associated with peri-implant health, although further research is needed to clarify this relationship. Overall, this study demonstrates the potential of cytological examination and Papanicolaou staining for assessing mucosal inflammatory conditions and distinguishing between keratinized and non-keratinized cells. These findings underscore the utility of oral mucosal smears as a valuable tool for diagnosing peri-implantitis and enhancing our understanding of its pathogenesis.

Comparative Study of Cell Findings by Conventional Smear and Liquid-Based Cytology for Oral Exfoliative Cytology

Background: Liquid-based cytology (LBC) is a method of manufacturing cyto-diagnostic specimens. Improved accuracy is expected from standardizing specimen production and use of this method is rapidly spreading in oral cytology. On the other hand, LBC reportedly requires training to show peculiar cell findings compared to those of conventional smear cytology (CVC). Few studies have compared detailed cell findings for oral CVC and LBC. Objectives: The aim of this study was to compare cytological findings between CVC and LBC using cytomorphological image analysis. Materials and Methods: Cytological specimens were collected from 20 patients (negative for squamous neoplasia in 10, dysplasia in 5, squamous cell carcinoma in 5) and 5 controls of the tongue between January 2017 and December 2018. Two different preparation techniques were investigated cytomorphologically for CVC and LBC (BD CytorichTM). Results: LBC showed significantly higher cell numbers than CVC for all lesions. LBC-to-CVC ratio ranged from 9.52 (hyperkeratosis) to 1.87 (deep cells in oral squamous cell carcinoma (OSCC)). Nuclear area of normal, hyperkeratosis, and inflammation were significantly higher in LBC than those of CVC. Hyperchromasia was significantly more frequent with CVC than with LBC for hyperkeratosis, inflammation, dysplasia and OSCC. There was no significant difference in circularity between CVC and LBC among all lesions. Conclusion: Only one cytomorphological disadvantage was seen with LBC, in the form of decreased hyperchromasia. Further clarification of the advantages and disadvantages of LBC is needed, including management of precision and screening practices.

Minor Salivary Gland Tumors: A Retrospective Study of 37 Cases

Salivary gland tumors represent 2% - 6.5% of all head and neck tumors. Since salivary gland tumors have various clinical features and histological types, it is often difficult to diagnose and treat them. The aim of this study was to conduct a retrospective clinical-statistical analysis of 37 minor salivary gland tumors (MSGTs) treated in the Department of Oral Surgery at Nihon University School of Dentistry at Matsudo over a 16-year period. The frequencies and distributions of sex, age, occurrence site, preoperative examination (fine needle cytology and/or biopsy), treatment, and prognosis of the tumors were analyzed and compared with previous reports. The average age at diagnosis was 58.1 years (range 22 - 91 years). The peak occurrence of tumors was in the sixties (10 cases, 27.0%), followed by the forties (8 cases, 21.6%) and the seventies (7 cases, 18.9%). The average age of patients with benign tumors was 56.8 years (range 22 - 91 years). For malignant tumors, the average age was 61.7 years (range 42 - 81 years). The male-female ratio was 1:2.1 for all minor salivary gland tumors, 1:2.4 for benign tumors, and 1.5:1 for malignant tumors. There were 27 (73.0%) benign and 10 (27.0%) malignant tumors. Pleomorphic adenoma (PA) was the most common tumor (24 (64.9%) cases). Most salivary gland tumors originated from the palate (21 cases, 56.8%);the second most common site was the buccal mucosa (14 cases, 37.8%). For most patients, an intraoral mass was the primary presentation, and the second most common symptom was swelling. Surgical treatment was performed for all cases, both benign and malignant tumors. There was one case of local recurrence of PA, as well as one of multiple lung metastases after surgery for adenoid cystic carcinoma. Diagnosis and treatment of MSGTs are often delayed because the patients have few symptoms, and it is difficult to distinguish benign from malignant tumors. More cases need to be examined in the future, and the diagnostic accuracy of imaging and histopathological diagnosis needs to be improved.

Histopathological and Immunohistochemical Study of the Distinction between Oral Lichen Planus and Oral Lichenoid Lesions

Background: Oral potentially malignant disorders, which include oral lichen planus (OLP), are clinical presentations that carry a risk of development to cancer in the oral cavity. Oral lichenoid lesions (OLLs) are also termed interface/lichenoid mucositis. Malignant transformation of them remains controversial, but distinct clinical and histological criteria for how to differentiate OLP from OLLs have not been developed. Objectives: The purpose of this study was to elucidate findings that can allow histopathological differentiation of OLP and OLLs using histomorphological and immunohistochemical analyses. Materials and Methods: Analyses were performed in 10 cases diagnosed with OLP and 9 cases diagnosed with OLLs. Cytokeratin 19 (CK19), Ki-67 and CD3 were used as primary antibodies to detect basal cells, proliferative activity and T-cell distribution, respectively, and Perlecan and COX-2 to evaluate epithelial intracellular arrangements and interstitial distributions of proteoglycans and enzymes. Results: For CK19, positive cells were significantly found in OLLs at both the prominent area and site adjacent to the lesion comparison with those of OLP’s. The number of COX-2 positive cells was significantly higher in spinous and basal layers in OLLs of the prominent area. Additionally, OLLs showed mild to moderate expression for perlecan in the basal to spinous layers and in subepithelial tissue. Conclusion: Almost no basal cells were noted in the prominent area in OLP. COX-2 and perlecan were found in the basal to spinous layers in OLLs. Although there are restrictions, these suggested the possibility of helping to distinguish between OLP and OLLs.

Nontraumatic Myositis Ossificans in a Muscle of Mastication

Myositis ossificans (MO) is an extraskeletal tumor-like lesion with bone formation, and is relatively rare in the head and neck region. We report herein a clinicopathological analysis of MO associated with a muscle of mastication. The patient was a 70-year-old Japanese woman who presented with a tumorous mass in the right parotid area and no history of trauma. The surgically excised tumorous lesion consisted of proliferating fibroblastic cells with no atypia in the central portion, and a formation of trabecular osteoid and/or bony tissue in the peripheral portion as the so-called “zonal phenomenon”. The final histological diagnosis was MO, and the lesion was located in the posterior belly of the digastric muscle on computer tomography. A review of the literature showed that many cases of MO predominantly affected the medial pterygoid and masseter muscle and showed a history of previous trauma. The present case represents a rare case of nontraumatic MO in the uncommon location of the posterior belly of the digastric muscle.

Pleomorphic Adenoma Consisting of Multiple Cysts with Squamous Epithelial Lining: Findings on MRI, FNAC, and Histopathological Examination

The incidence of pleomorphic adenoma (PA) of the minor salivary glands is reported to be 10%, and while the histological findings in PA can be diverse, keratin-filled cysts lined by squamous epithelium are rarely reported. The condition can, however, present with cyst formation in some cases. We review a rare case of pleomorphic adenoma in the buccal mucosa that involved the formation of multiple squamous epithelium-lined cysts in a 69-year-old woman. Magnetic resonance imaging (MRI), fine needle aspiration cytology, and histopathological examination were performed. Physical examination revealed a painless, mobile, elastic hard mass in the right buccal mucosa, measuring 2.5 × 1.0 cm. The MRI revealed a well-defined lesion with different signal intensities in the medial and distal regions of the right cheek. The medial side of the lesion showed a low signal intensity on T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI), while the distal side showed a low signal intensity on T1WI, and a high signal intensity on T2WI and short tau inversion recovery (STIR) imaging. Fine needle aspiration of the lesion was performed under local anesthesia and a cytological diagnosis of an epidermoid or dermoid cyst was made. The tumor was completely resected under local anesthesia combined with intravenous sedation. The histopathological examination demonstrated the proliferation of atypical tumor cells with poor atypia and the formation of glandular, alveolar, large, and small cysts. The cysts were lined by keratinized squamous epithelial cells, their cavities were filled with keratinous material, and foreign body reaction was observed after rupture. Histopathological evaluation led to the diagnosis of pleomorphic adenoma. The patient had no evidence of recurrence, 2 years and 3 months after the surgery. In conclusion, the presence of multiple cysts lined by squamous epithelium can pose a significant diagnostic challenge in patients with PA. It is important to make the correct diagnosis in order to avoid unnecessarily aggressive therapy.

Comparative Study of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry and Culture Test for <i>Candida</i>Identification

Background: A new microorganism identification method using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) has been developed, however, reports on its use for delineating Candida spp. are scarce. Objectives: The purpose of this study was to compare the identification accuracy of mixed infection between culture test and MALDI-TOF MS. Materials and Methods: Eighty-nine denture wearers (average 74.0 ± 9 years) were selected. Specimens were immediately inoculated onto selective medium for CHROMagarTM Candida, and were also carried out using MALDI-TOF MS. The distribution frequencies of them were analyzed. Results: The numbers and rates of detection/non-detection by MALDI-TOF MS of genus Candida were 58/31 (65.2%/34.8%), respectively. Infection types were single infection in 34 (38.2%), mixed infection in 24 (27.0%), and non-infection in 31 (34.8%) cases. Concerning the single infection, C. albicans was the most predominant (58.8%), followed by C. parapsilosis (17.6%), C. glabrata (14.7%), C. tropicalis (5.9%), and C. krusei (2.9%). As for the mixed infection, the most frequent combination was C. albicans and C. glabrata (50.0%), followed by C. albicans and C. parapsilosis (29.2%), C. albicans and C. tropicalis (8.3%), C. glabrata and C. tropicalis (4.2%), C. albicans, C. glabrata, and C. parapsilosis (4.2%), and C. albicans, C. parapsilosis, and C. glabrata (4.2%). There were four MALDI-TOF MS positive results that were negative by the culture test. Conversely, there were six MALDI-TOF MS negative results that were positive by the culture test. The sensitivity and specificity of MALDI-TOF MS were 0.929 and 0.840, respectively. The concordance rate of genus Candida was 0.644, indicating substantial agreement. Conclusion: Candida infection is complicated by disease type and oral cavity environment changes due to aging. A rapid microorganism detection method, such as MALDI-TOF MS, will be helpful to quickly determine the causative pathogen in dental infections.

Histopathological, Immunohistochemical and Exfoliative Cytological Studies of Oral Verruciform Xanthoma

Verruciform xanthoma is a rare tumor-like lesion, predominantly affecting the oral mucosa. Although several studies of verruciform xanthoma have been reported, the characteristic features and pathogenesis have not been fully clarified. The purpose of the present study is to perform immunohistochemical analysis using markers of proliferative cell activity and cytokeratins, and to perform comparative analysis between cytological and histological features in order to clarify the characteristic features of verruciform xanthomas. Histological findings showed exophitic proliferation of stratified squamous epithelium and accumulation of foamy macrophages between epithelial processes. Immunohistochemically, accumulated foamy cells showed positive immuno-reactivity for CD68, and positive cells were also present in the epithelium. Expression of pancy-tokeratin was observed in most layers of the epithelium, whereas cytokeratin 13 was also detected in prickle cell layers. Positive reactivity for Ki-67 was observed in epithelial cell nuclei. Positive reactivity was largely distributed in basal and/or parabasal cell layers, and the positive cell rate was 20%. In addition, exfoliative cytological findings showed hyperkeratotic epithelial cells with picnosis, thus suggesting the characteristics of hyperplastic epithelium in verruciforma, although foamy cells were not observed in the cytological specimens. These results suggest that benign morphological characteristics with local cellular immune response of verruciform xanthoma may be evaluated based on immunohistochemical expression of cytokeratin and Ki-67, as well as exfoliative cytological findings.

Histopathological Examination and Literature Review of Orthokeratinized Odontogenic Cyst

Background: With transitions in the disease concept of orthokeratinized odontogenic cyst (OOC), the pathogenesis and etiology have not been sufficiently elucidated. Objectives: OOC cases were reclassified and observed to understand the clinico-histopathological characteristics. In addition, literature review of OOC was performed to better organize the pathology. Materials and methods: Subjects with jawbone cysts lined by keratinized stratified squamous epithelium from 2005 to 2018 were reclassified, and clinico-histopathological findings were analyzed. Previous reports of OOC/orthokeratinized-type odontogenic keratocyst (OKC) from 1980 to 2019 were organized. Results: Five cases of OOC were diagnosed, representing 2.1% of odontogenic developmental cysts (total, 239 cases). Mean age was 37.6 years, with a female predominance. The mandibular molar area was the frequent site, and all cysts were solitary. Sixty percent involved an impacted tooth. Mean maximum diameter of the cyst was 2.2 cm. Histopathologically, 4 cases were unilocular, and partial palisading of the basal layer and scattered epithelial islands were observed in 2 cases each and formation of daughter cysts was noted in 3 cases. Previous papers described that most were unilocular and related to impacted teeth. Mean age ranged between 20 and 40 years, and the mandibular molar region was dominant. Recurrence rates were low. Conclusion: OOC shows a different biological attitude to OKC and is closer to dentigerous cyst. Meanwhile, OOC shows a similar histology of epidermoid cysts accompanying the granular layer. We thus surmised that OCC represents an independent concept as an odontogenic developmental cyst.