Abstract A 9‐year‐old mixed‐breed dog was presented with a bleeding oral mass on the gingiva. The gingival mass had been present for over a year before it started to bleed. Histopathology after surgical excision revealed a rare collision tumour composed of gingival haemangiosarcoma and peripheral odontogenic fibroma with incomplete margins. Follow‐up imaging identified multiple pulmonary nodules and subcutaneous masses, with biopsy confirming metastatic haemangiosarcoma. The patient underwent five cycles of doxorubicin chemotherapy, which was well tolerated but did not slow metastatic progression. Subsequent treatments included mass excision for palliation and oral piroxicam; however, acute kidney injury and neurological signs later developed. The patient ultimately deteriorated and died 208 days after diagnosis. This case highlights an uncommon oral presentation of haemangiosarcoma and the diagnostic challenges of mixed tumours.

A tumour is an abnormal mass of tissue that exceeds normal boundaries, resulting from uncoordinated and uncontrolled cell proliferation. Histopathology is considered to be gold standard test for tumours diagnosis. However more accurate diagnosis require more advanced techniques like immunohistochemistry. It is a powerful diagnostic tool, and choice of its selection depends on nature of tumour. The present study aimed to explore the pathology of Mesenchymal tissue neoplasms particularly Histopathology, Immunohistochemistry. Among the 32 mesenchymal benign neoplasms, angiofibroma was seen in 15 cases followed by angiolipoma (3), neurofibroma (3), ossifying fibroma (3), peripheral odontogenic fibroma (2) and each case of melanocytoma, hemangioma and lipoma. While 11mesenchymal malignant neoplasms included leiomyosarcoma (3) melanoma (2), fibrosarcoma (2) and one each case of hemangiosarcoma, chondrosarcoma, liposarcoma and malignant peripheral nerve sheath tumour.

eP038 Rare finding of a malignant sclerosing odontogenic carcinoma camouflaged as a benign odontogenic fibroma

Recurrent gingival nodule mimicking oral focal mucinosis: A case report highlighting diagnostic challenges in peripheral odontogenic fibroma

Peripheral Odontogenic Fibroma (POF) is a benign neoplasm originating from oral mesenchymal cells, affecting gingival, pharyngeal and rarely esophageal tissues. In the veterinary literature, there is a greater recurrence in large and medium-sized dogs, however it can affect all breeds. This work reports the case of diagnosis and treatment of a FOP in the mandibular region in a castrated female dog of the French Bulldog breed, highlighting which changes could be noticed in blood tests, methods of confirming the type of lesion and how tumor excision and animal recovery.

Peripheral odontogenic fibromas (POFs) are benign masses of mesenchymal cells with features of periodontal ligament/gingival ligament fibroblasts and are among the most commonly diagnosed oral masses in dogs. Recently, a subset of hypercellular POFs (hPOFs) has garnered attention due to atypical histologic features giving concern for malignant potential. This retrospective study describes 54 hPOFs characterized by increased cellularity, increased pleomorphism, increased mitotic count, and/or bony remodeling in the absence of inflammation. Data collected from records included signalment, degree of excision, and location of the mass. Follow-up questionnaires were distributed to referring veterinarians to assess biologic behavior and patient outcomes. The hPOFs represented 76/6303 (1.2%) of all canine POF diagnoses in a 12.6-year time frame. Of 29 cases where follow-up data were available, 4/29 (14%) experienced local recurrence, similar to published recurrence rates of typical POFs. No evidence of malignant behavior nor metastasis was identified in any case. The median survival time (17 months) was greater than the median follow-up time for living patients (14 months), and the deaths of 14 patients were all attributed to unrelated illnesses. These results suggest that despite concerning histologic features, hPOFs are not associated with a shorter survival time, nor do they carry a greater risk of local recurrence or metastasis relative to histologically typical POFs. Our findings suggest that hPOFs can be clinically managed similar to typical POFs. Pathologists presented with POFs with hypercellularity, increased pleomorphism, increased mitotic count, and bone remodeling should be aware of hPOF as a potential diagnosis.

Introduction: Odontogenic tumors are the expansile group of jaw neoplasm that originates from the tooth-forming tissues. WHO, revised classification several times due to their discrete histological and biological behavior. They were broadly classified as benign and malignant tumors, the former being the most common. Benign tumors are classified into epithelial, mixed (epithelial and mesenchymal), and mesenchymal lesions based on their histogenetic origin. Materials and Methods: 1. To evaluate the various types of odontogenic tumors diagnosed in the Department of Oral Pathology. 2. To correlate the clinical data and histological features of odontogenic tumors diagnosed. Clinical data of all the odontogenic tumors were collected retrospectively from the 10-year archives of the Oral Pathology Department, GITAM Dental College and Hospital, Visakhapatnam. The tumors were classified according to the WHO classification. Clinical and histopathological evaluations wasere doneperformed for all the odontogenic tumors. Different histological characteristics were compared; tabulated and analyzed. Results: A total of 105 cases of odontogenic tumors were recorded. 82% account for benign tumors, and 18% for malignant tumors. Epithelial origins comprise the majority of benign tumors (48%), followed by mesenchymal and mixed odontogenic tumors (20% and 14%, respectively). Unicystic ameloblastoma is the most common odontogenic tumor, accounting for 18 (17%) cases, followed by conventional ameloblastoma, odontogenic fibroma, ameloblastic carcinoma, and odontoma. Odontogenic tumors were reported mostly during the second, third, and fourth decades of life. Male predilection was observed over females in all the odontogenic tumors. All forms of OT were detected in the posterior mandible. Epithelial odontogenic tumors predominate in all four anatomical sites, except the posterior maxilla, where mesenchymal OT was somewhat more common and no malignant odontogenic tumor was seen. Conclusion: The variability in data from this study can be ascribed to a variety of demographic factors. Hence, the need to incorporate specific lesion histopathology and diagnostic molecular interventions would make results more sensitive catering to research needs.

A series of hybrid central giant cell granuloma/central odontogenic fibromas

Central odontogenic fibroma (COF) is a rare benign tumor originating from periodontal tissues. Although it typically grows slowly and remains asymptomatic, COF can cause significant complications when neglected, including displacement of teeth, bone destruction, and even life-threatening airway obstruction.

The study investigated the distribution, types, and geographic distribution of oral tumors in cats in Switzerland, providing insights into demographics, tumor features, and emerging trends. We analyzed pathology records of oral tumors in cats diagnosed between 2012 and 2022 from diagnostic laboratories in Switzerland. Only histologically confirmed neoplasms were included; inflammatory and cystic lesions were excluded. Geographic distributions were assessed using postal addresses. Among 339 reports of oral tumors in cats, 294 met inclusion criteria. Malignant tumors dominated 82.0% (241 of 294), with squamous cell carcinoma most prevalent (70.5% [170 of 241]), followed by fibrosarcoma (7.2% [19 of 241]), melanoma (4.6% [11 of 241]), and adenocarcinoma (4.6% [11 of 241]). Benign tumors represented 18.0% (53 of 294), mostly with peripheral odontogenic fibroma (8.2% [24 of 294]). Squamous cell carcinoma was commonly located on the tongue (24.0% [33 of 137]), accounting for all tumors identified in the sublingual region (100% [17 of 17]). Peripheral odontogenic fibroma occurred mainly in caudal mandibles (41.7% [10 of 24]). Histopathologic analysis revealed that ulceration and necrosis were frequent in malignant cases, with a broader range and higher mitotic indices (P < .0001). The European Shorthair was the most commonly represented breed (80.6% [237 of 294]), and older cats (median age 13 years) were most affected. The results emphasize the high frequency of malignant oral tumors, particularly squamous cell carcinoma, in cats in Switzerland, consistent with trends observed in other regions, and identified distinct histopathologic characteristics differentiating malignant from benign cases. Investigating the prevalence, types, and geographic distribution of oral tumors in cats in Switzerland may support awareness, early detection, accurate diagnosis, and potentially better clinical outcomes.

In this case report, the characteristics, diagnosis, and treatment approaches of central odontogenic fibroma, a very rare tumor, are described. A systemically healthy 29-year-old female patient was admitted to our clinic for routine checkups. Intraoral examination revealed a depression in the lingual gingiva of the right mandibular premolar region. Radiographic examination revealed a mixed, multilocular lesion in the right mandibular canine-premolar region with prominent cortical borders. Botryoid odontogenic cyst was considered in the differential diagnosis. A puncture biopsy of the lesion area was negative. With this finding, the lesion was thought to be a solid mass, and incisional biopsy was performed. On histopathologic examination, the lesion was diagnosed as central odontogenic fibroma. The lesion was excised under local anesthesia. After 18 months of follow-up, no recurrence was observed.

Peripheral odontogenic fibroma (POF) is a rare benign mesenchymal odontogenic tumor presenting as a firm gingival mass. Diagnosing POF is challenging due to its morphological similarity to other reactive gingival lesions. This case report discusses an 11-year-old boy with a painless palatal gingival mass, diagnosed through clinical, radiographic, and histopathological evaluations. The lesion was excised under local anesthesia, confirming POF. The rarity of maxillary POF in children underscores the importance of accurate diagnosis and follow-up to prevent recurrence. Key Words: Anesthesia, Lesion, Tumor

Global frequency of the peripheral odontogenic fibroma: a systematic review and meta-analysis

Updated and comprehensive epidemiological data on odontogenic tumors are not available for the Nordic countries. The aim of the study was to retrospectively examine the prevalence and clinical and radiological characteristics of primary odontogenic tumors over a 10-year period in Sweden, Norway, Finland, and Denmark. Primary odontogenic tumors diagnosed by oral pathologists from 2010 to 2020 at nine different diagnostic laboratories in Sweden, Norway, Finland, and Denmark were identified. Using histopathology referrals and their corresponding histopathological reports, age and sex, anatomic site, clinical and radiological findings, tentative diagnosis, histopathological diagnosis, and recurrence of the tumors were recorded. Range, mean, and median for continuous variables and frequency tabulation for discrete variables were used. In total, 1139 primary odontogenic tumors (598 in males and 540 in females) were identified during the study period, giving an annual incidence rate of 4.2/million. The mean age of all patients was 29 years. Ninety-nine percent of the tumors were benign, and the mandible was the predominant location. Odontoma, ameloblastoma, and odontogenic fibroma were the three most common tumors. The mixed epithelial and mesenchymal benign odontogenic tumors were more common at a younger age compared with the epithelial tumors and the mesenchymal tumors (mean age 22, 44, and 35 years, respectively). Information on variables other than sex, age, and tumor site was missing in most referrals. The annual incidence of 4.2 cases per million indicates that odontogenic tumors are uncommon in Nordic countries. Better practices to improve the quantity and quality of clinical information in the pathology referrals are needed.

Background: Peripheral odontogenic fibroma (POF) is a rare benign mesenchymal odontogenic tumor, representing only 0.05% of biopsy specimens. Despite its rarity, POF is considered the most prevalent peripheral odontogenic tumor. Conducting a systematic review is essential to determine the predominant epidemiological, clinical, and histological characteristics of POF, assisting dentists in similar cases. Aim: This study aimed to elucidate the epidemiological, clinical, and histological characteristics of POF through a systematic review. Methods: The systematic review followed the PRISMA criteria. The clinically relevant question was: What is the epidemiological, clinical, and histological profile of POF. Articles in English were included, with individuals (humans) with a histological diagnosis of POF. Literature review articles that did not define the type of lesion were excluded. The search was conducted in several databases until December 2016. Results: Of the 964 articles, only 49 were eligible. The most frequent epidemiological characteristics were white women between the 2nd and 4th decades of life. Clinically, the lesions were located mainly in the mandibular gingiva, with characteristics of a nodule, ulcerated or not, sessile, red, smooth, or lobed surface, and an average size of 1.71 cm. The main histopathological findings were the absence of ulceration of the superficial epithelium, fibrocellular connective tissue, with or without calcifications, non-encapsulated lesion, with abundant or scarce presence of islands and strands of odontogenic epithelium. Conclusion: This topic requires more articles with a higher level of scientific evidence, such as a systematic review, requiring greater scientific rigor in the quality of these articles.

Determine the prevalence, types, and geographical distribution of oral tumors in dogs in Switzerland to provide insights into demographics, tumor characteristics, and trends. The medical and pathology records of dogs diagnosed with oral tumors from 2012 to 2022 were sourced from diagnostic laboratories in Switzerland. The focus was on histopathologically confirmed oral neoplasms. Inflammatory, viral, and cystic lesions were excluded. Geographic trends were analyzed by use of postal addresses, revealing local distributions. Of the 948 reports, 773 cases fulfilled the study's criteria. Benign tumors constituted 63% (487 of 773), with peripheral odontogenic fibroma being the most common (77.8% [379 of 487]). Among the malignant tumors, malignant melanoma was the most frequent (38.1% [109 of 286]), followed by squamous cell carcinoma (21% [60 of 286]) and fibrosarcoma (8% [23 of 286]). The locations of tumors varied, with a higher prevalence of malignant melanoma on the lips. Histopathologic findings indicated ulceration and necrosis were more common in malignant tumors. Significant differences were noted in the mitotic index between benign and malignant groups. No tumor predisposition was noted for any breed. Oral tumors were prevalent in older dogs (median age, 9.4 years). The findings highlighted the predominance of benign tumors in dogs in Switzerland, with specific histopathologic features distinguishing benign from malignant cases. Understanding the prevalence, types, and geographic distribution of oral tumors based on the representation in dogs in Switzerland may aid in early detection, appropriate diagnostic workup, and informed treatment planning for oral tumors in dogs.

Surgical Management with Histopathology of Peripheral Odontogenic Fibroma in a Calf: A Case Report

Central odontogenic fibroma (COF) is a rare benign tumor from odontogenic mesenchyme, accounting for less than 5% of odontogenic tumors. Central giant cell granuloma (CGCG) is also benign but locally aggressive, featuring multinucleated giant cells in a fibrovascular stroma. Hybrid lesions with features of both COF and CGCG are extremely rare, with fewer than 50 cases reported. This paper presents a case of a hybrid COF-CGCG lesion in a 33-year-old female with an asymptomatic, well-defined unilocular radiolucent lesion between mandibular premolars, causing root resorption and tooth displacement. Histopathological analysis revealed a mixture of inactive odontogenic epithelium and multinucleated giant cells embedded in a dense, collagenized stroma. The patient showed no signs of recurrence after six months of follow-up. This case highlights the rarity and diagnostic challenges of COF-CGCG hybrid lesions, emphasizing the need for further research to understand its pathogenesis and guide management.

In light of the lack of reliable molecular markers for odontogenic myxoma (OM), the detection of copy number variation (CNV) may present a more objective method for assessing ambiguous cases. In this study, we employed multiregional microdissection sequencing to integrate morphological features with genomic profiling. This allowed us to reveal the CNV profiles of OM and compare them with dental papilla (DP), dental follicle (DF), and odontogenic fibroma (OF) tissues. We identified a distinct and robustly consistent CNV pattern in 93.75% (30/32) of OM cases, characterized by CNV gain events in chromosomes 4, 5, 8, 10, 12, 16, 17, 20, and 21. This pattern significantly differed from the CNV patterns observed in DP, DF, and OF. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated potential links between this CNV patterns and the calcium signaling pathway and salivary secretion, while Gene Ontology (GO) term analysis implicated CNV patterns in tumor adhesion, tooth development, and cell proliferation. Comprehensive CNV analysis accurately identified a case that was initially disputable between OF and OM as OM. Our findings provide a reliable diagnostic clue and fresh insights into the molecular biological mechanism underlying OM.

A generalizable procedure for Brown's class Ⅱ and Ⅲ defects reconstruction with deep circumflex iliac artery flap using computer-assisted technique