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Background: Uremic stomatitis is often unfamiliar to healthcare professionals. This study presents five cases of uremic stomatitis, providing a comprehensive analysis of their demographic distribution, clinicopathological features, and management strategies based on existing literature. Methods: Data were collected from centers across Brazil, Argentina, Venezuela, and Mexico. Electronic searches were conducted in five databases supplemented by manual scrutiny and gray literature. Results: The series consisted of three men and two women with a mean age of 40.2 years. Lesions mostly appeared as white plaques, particularly on the tongue (100%). The median blood urea level was 129 mg/dL. Histopathological analysis revealed epithelial changes, including acanthosis and parakeratosis, with ballooned keratinocytes in the suprabasal region. Oral lesions resolved subsequent to hemodialysis in three cases (75%). Thirty-seven studies comprising 52 cases of uremic stomatitis have been described hitherto. Most patients were male (65.4%) with a mean age of 43.6 years. Clinically, grayish-white plaques (37.3%) and ulcers/ulcerations (28.9%) were common, particularly on the tongue (30.9%). Hemodialysis was performed on 27 individuals. The resolution rate of oral lesions was 53.3%. Conclusion: Earlier recognition of uremic stomatitis, possibly associated with long-term uremia, holds the potential to improve outcomes for patients with undiagnosed chronic kidney disease. [ABSTRACT FROM AUTHOR]

Phleboliths are reported as calcifications that occur in vascular malformations, associated with changes in blood flow dynamics, thrombus formation and subsequent calcifications. Radiological examination, such as cone beam computed tomography (CBCT) could help in demonstrating the presence of a calcifiied mass. A 45-year-old male was referred to our service with an asymptomatic nodular purplish lesion located on the ventrolateral tongue. Within the lesion, a stony mass was also evident on palpation. A digital dental radiograph demonstrated two circumscribed radiopaque structures. Phleboliths associated with vascular malformation was the main diagnostic hypothesis. The patient underwent a sclerotherapy protocol allowing surgical accessibility to the area. Phlebolyts were surgically removed using electrocoagulation. Histopathological examination revealed phleboliths in the context of a vascular malformation with intense fibrosis. [ABSTRACT FROM AUTHOR]

Background: Oral lesions of immune-mediated and autoimmune diseases have been well-documented, but studies from Brazil are limited. The varied spectrum of oral lesions within this demographic group poses challenges to clinicians, particularly when they occur in isolation. This study aimed to evaluate the occurrence, clinical characteristics, and management of patients with oral lesions of immune-mediated and autoimmune diseases at a single center in Brazil. Methods: A retrospective cross-sectional study was conducted from 2010 to 2022. Clinicodemographic data, histopathological features, and treatment modalities were analyzed descriptively and analytically. Results: Of the 3,790 oral and maxillofacial lesions diagnosed, 160 (4.2%) were confirmed as immune-mediated or autoimmune diseases. The population surveyed predominantly consisted of women (73.7%), with a mean age of 60.2 years. Oral lichen planus (51.3%), mucous membrane pemphigoid (MMP) (23.7%), and pemphigus vulgaris (PV) (19.4%) were the most prevalent lesions. The buccal mucosa (59.4%) was predominantly affected, with pain reported in 46.2% of cases, notably in individuals with PV and MMP. The average time to disease stabilization post-local and/or systemic corticosteroid therapy was 15.8 months for systemic lupus erythematosus, 8.7 months for MMP, and 6.5 months for PV. Conclusion: Although oral lesions related to immune-mediated and autoimmune diseases are uncommon, their diverse clinicopathological aspects require multidisciplinary management. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate the clinicopathological features of metastases in the oral and maxillofacial regions. Methods: In this retrospective study, biopsy records were obtained from referral centers for oral and maxillofacial diagnosis in Brazil, Guatemala, Mexico, and South Africa. Results: A total of 120 cases were evaluated. Of these, 53.78% affected female patients, with a mean age of 57.64 years. Intraosseous lesions were more frequent, particularly in the posterior region of the mandible (49.58%). Clinically, most cases presented with symptomatic swelling, with an average evolution time of 25 months. The clinical diagnostic hypothesis in most instances was that of a malignant lesion. Breast cancer was the most common primary tumor location in females, while lung origin was most common in males. In most cases, the primary cancer was an adenocarcinoma (44.73%). The follow-up period was available for 29 cases, and out of these, 20 had died due to the disease. Conclusion: Although this is a rare condition, clinicians should be aware that any oral lesions have the possibility of being metastatic, particularly in individuals with a previous history of cancer. The findings from this study could assist clinicians in prompt diagnosing these lesions and subsequent conducting oncologic assessments and treatment. [ABSTRACT FROM AUTHOR]

A 56-year-old Brazilian woman sought dental care, presenting with multiple asymptomatic papillomatous lesions with a coalescent pattern and intermingled cobblestone-like clefts along the alveolar ridge and marginal and attached gingivae. Multiple whitish papules were also observed on the face, neck, and limbs. Incisional biopsies of these lesions were performed. Microscopically, the skin lesion revealed epithelial clear cells and intraepithelial keratinization with areas of orthokeratosis, while the gingival lesions showed a parakeratinized stratified squamous epithelium with collagenous connective tissue. These features were consistent with those of a trichilemmoma and fibroepithelial hyperplasia, respectively. This article illustrates a case of Cowden syndrome (CS), a rare multisystem genetic condition in which both cutaneous and mucosal tissues were affected. Fewer than 40 cases of CS with oral involvement affecting middle-aged adults have been documented hitherto. [ABSTRACT FROM AUTHOR]

Squamous odontogenic tumor (SOT) is a rare benign but locally infiltrative tumor often misdiagnosed as other entities, such as ameloblastoma and squamous cell carcinoma, due to overlapping morphological findings. We document here the clinicopathological and imaging findings of an aggressive intraosseous SOT in the posterior left region of the maxilla in a 25-year-old male patient. On intraoral examination, the tumor extended from the region of the left lateral incisor to the upper left premolar and was covered by reddish mucosa, with discrete areas of ulceration. Imaging exams revealed an osteolytic lesion causing thinning, erosion, and buccal and lingual cortical plate perforation associated with an impacted canine. Microscopically, the tumor showed a proliferation of islands of well-differentiated squamous epithelium in a variably collagenized background. The peripheral cells of the islands were flat or slightly cuboidal and did not exhibit nuclei with peripheral palisade and reverse polarization. The diagnosis of SOT was rendered. The patient underwent surgical resection and has been under clinical follow-up for approximately 12 months with no signs of recurrence. A careful morphological evaluation is essential to avoid misdiagnosis and ensure a satisfactory treatment approach. [ABSTRACT FROM AUTHOR]

Juvenile xanthogranuloma (JXG) is the most common form of non-Langerhans cell histiocytosis in childhood. It often presents with cutaneous involvement and exhibits a predilection for the head and neck region. This article illustrates a case of congenital JXG in a 5-month-old boy, characterized by a solitary, well-circumscribed nodule above the left upper lip. Histopathologically, the lesion exhibited histiocytes with eosinophilic cytoplasm and Touton giant cells. Immunohistochemistry revealed histiocytes positive for CD68 and Factor XIIIa, while negative for S-100 protein. Clinicians should become familiar with the broad clinical spectrum of cutaneous JXG, particularly its congenital presentation, in order to ensure timely and accurate management. [ABSTRACT FROM AUTHOR]

Melanotic neuroectodermal tumor of infancy (MNTI) is a rare benign neoplasm that can be mistaken for malignancies due to its unfamiliarity among clinicians and aggressive clinical appearance. We herein contributed by reporting an additional case of MNTI characterized by an extensive extraoral protrusion in a 2-month-old infant. The lesion involved the anterior maxilla, cheek, and infraorbital region, resulting the displacement of the nose to the contralateral side, and measuring approximately 10 cm in size. Surgical resection of the lesion was performed. After a 6-month follow-up, the patient has shown no evidence of recurrence. The rapid growth and aggressive behavior of MNTI emphasize the importance of an early diagnosis and prompt intervention in order to achieve favorable outcomes. [ABSTRACT FROM AUTHOR]

Background: Dermal facial fillers are increasingly popular. Published reports on the clinical and histopathologic characteristics related to adverse reactions to dermal fillers in the facial region have been relatively well documented. This study adds to the literature on adverse reactions to injected filler in the oral and maxillofacial region in a South American population. Methods: A retrospective, descriptive cross-sectional study (2019–2020) was performed. The study population was a dermatology service in Venezuela. Clinical and histopathologic features of patients with adverse effects were documented. Results: A total of 35 cases of adverse reactions associated with cosmetic filler procedures were diagnosed during the analyzed period; of these, six cases (17.1%) involved the oral and maxillofacial region. All cases occurred in women. The mean age at diagnosis was 59.3 years (58–73). In three cases, dermal fillers were used in different locations on the face, while three involved the lips. Five patients exhibited adverse reactions to lip filler. All six cases were histopathologically diagnosed as foreign body reactions to injected material. Four and two cases revealed microscopic features compatible with hyaluronic acid and polymethylmethacrylate, respectively. Conclusion: Reflecting the dramatic increase in cosmetic procedures with soft tissue fillers, this study contributed by reporting six cases of foreign body reaction involving the oral and maxillofacial region, confirmed with biopsy and histopathology. [ABSTRACT FROM AUTHOR]

Background: Congenital melanotic macule of the tongue (CMMT) has been described as a distinct entity, despite its unknown etiology. However, the diagnosis and management of affected newborns may challenge clinicians and pediatric dentists. Methods: We document here the clinicopathological findings of two additional cases of CMMT. A literature review of CMMT reports identified across PubMed, Web of Science, Embase, and Scopus was also conducted. Results: The patients, 2- and 4 month-old Venezuelan boys, respectively, presented at birth with a single or multiple dark-brown-pigmented macule exclusively on the dorsum of the tongue. Histopathological features revealed increased melanin pigmentation in the basal epithelial layer with overlying hyperkeratosis and pigment-laden subepithelial macrophages with normal morphological appearance. Nine studies comprising 17 cases of CMMT have been described hitherto. Most cases were from the USA and France (n = 6 each). Twelve (70.6%) patients were males, eight (50%) were white, and median age was 2.7 months. CMMT presented as brownish to black, solitary or multiple pigmentations located in the right or left region of the dorsum of the tongue, ranging in size from 3.0 to 30.0 mm. Conclusion: An important feature for the diagnosis of CMMT is the information about the manifestation at birth and consequent proportional growth. This report intends to draw the attention of pediatricians and dentists to this apparently underdiagnosed condition for decision-making and management of affected newborns. [ABSTRACT FROM AUTHOR]

Background: Leishmaniasis is a tropical disease caused by protozoan parasites of the genus Leishmania. Mucosal leishmaniasis has been described as secondary to the cutaneous form; however, isolated mucosal involvement can also occur. Specifically, mucosal leishmaniasis of the lip is poorly described and its diagnosis challenges clinicians. Methods: We herein report a case of mucosal leishmaniasis affecting the lower lip without cutaneous involvement in a 20-year-old Venezuelan man. The patient had no relevant past medical history. Clinically, a mass-like lesion with ulcerations and crusts was observed. Results: Microscopically, the lesion was composed of granulomatous inflammation along with macrophages containing intracytoplasmic inclusions similar to round-shaped Leishmania. The species Leishmania (Viannia) braziliensis was confirmed. Treatment with meglumine antimonate was effective. The lesion healed satisfactorily, and no side effects or recurrences were observed. Conclusion: Clinicians should be aware of isolated forms of mucosal leishmaniasis of the lip, even in cases where the cutaneous lesion is undetected or clinically manifests as self-limiting. Knowing the endemic areas in the scenario of the dynamics of the ecoepidemiology of leishmaniasis is also essential for surveillance and counselling of the population. [ABSTRACT FROM AUTHOR]

Background: Lymphomas affecting the sublingual glands are extremely rare and very few case reports are currently available. Therefore, the aim of the current study is to describe the clinicopathological features of a series of lymphomas involving the sublingual glands. Methods: Cases diagnosed in four pathology services were assessed and the formalin-fixed paraffin-embedded tissue blocks were retrieved for diagnosis confirmation. Clinical data were obtained from patients' medical files. Results: We obtained seven cases of lymphomas in the sublingual glands, representing two follicular lymphomas, two diffuse large B cell lymphomas not otherwise specified (DLBCL NOS), two extranodal marginal zone B cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphomas) and one mantle cell lymphoma (MCL). In all cases the tumor cells infiltrated the glandular parenchyma, although in two of them the neoplastic cells were located more superficially and permeated the glandular acini and ducts. Clinically, the tumors presented as asymptomatic nodules and two patients (affected by DLBCL NOS and MCL) died, while the other five patients remained alive at last follow-up. Conclusion: Lymphomas affecting the sublingual glands are usually of the mature B cell lineage, often represent low-grade subtypes and may clinically resemble other more common lesions in the floor of the mouth like salivary gland tumors. [ABSTRACT FROM AUTHOR]

Diffuse large B cell lymphoma, not otherwise specified (DLBCL, NOS) is the most frequent non-Hodgkin lymphoma subtype. This aggressive neoplasm may variably express the CD30 protein, which may be used as a therapeutic target for this tumor. However, CD30 expression in DLBCL NOS arising from the oral cavity and the oropharynx has not been investigated. Therefore, this study aims to determine the frequency of CD30 expression and its prognostic significance for patients affected by oral/oropharyngeal DLBCL NOS. Fifty cases were retrieved from pathology files and submitted to immunohistochemistry against CD30. Reactivity was accessed by two oral pathologists using two cut-off values (> 0% and > 20% of tumor cells) to determine positivity in each case. Clinical data were obtained from the patients' medical files to investigate the prognostic potential of the protein. Seven high-grade B cell lymphomas and two EBV-positive DLBCL NOS were identified. We found one CD30-positive case in each of these two groups of lymphomas. Among the remaining 41 DLBCL NOS, other four cases (three in the oral cavity and one in the oropharynx) were positive for CD30, but only two expressed the protein in > 20% of tumor cells, both in the oral cavity. Survival analysis demonstrated that CD30-positive cases had a higher five-year overall survival rate (75%) than CD30-negative cases (32.3%), although a statistically significant result was not achieved (p = 0.19). Only a minor subset of oral and oropharyngeal DLBCL NOS express CD30 and these patients seems to have a higher survival rate. [ABSTRACT FROM AUTHOR]

Juvenile xanthogranuloma (JXG) is the most common form of non-Langerhans cell histiocytosis and oral mucosal involvement is exceedingly rare. Histiocytic disorders harbor activating mutations in MAPK pathway, including the report of BRAF V600E in JXG of extracutaneous site. However, no information is available for oral JXG. Herein, the clinicopathological and immunohistochemical features of five new oral JXG were evaluated in conjunction with literature review. Also, we assessed the BRAF V600E in oral samples. Five oral JXG were retrieved from pathology archives. Morphological and immunohistochemical analyses were performed. The BRAF V600E status was determined with TaqMan allele-specific qPCR. The series comprised of three female and two male patients, most of them adults, with a median age of 39 years (range 13–68 years). Clinically, the lesions appeared as asymptomatic solitary nodules, measuring until 2.5 cm, with more incident to the buccal mucosa. Morphologically, most of the cases presented classical histological features of JXG, with histiocytic cells consistent with the non-Langerhans cell immunophenotype. BRAF V600E was not detected in the cases tested. This is the first and largest published series of oral JXG affecting adults and a Brazilian population. The molecular pathogenesis of oral JXG remains unknown. Clinicians and pathologists must recognize JXG to avoid misdiagnoses with oral benign or malignant lesions. [ABSTRACT FROM AUTHOR]

Smooth muscle neoplasms represent an important group of lesions which is rare in the oral cavity. Leiomyoma (LM) is benign smooth muscle/pericytic tumor usually presenting as non-aggressive neoplasm, while leiomyosarcoma (LMS) represents its malignant counterpart. The rarity of these lesions, together with its unspecific clinical presentation and a variable histopathological appearance, lead to a broad list of differential diagnoses, hampering their diagnoses. Therefore, in this study we describe the clinical and microscopic features of a series of oral and maxillofacial LMs and LMSs. A retrospective search from 2000 to 2019 was performed and all cases diagnosed as LM and LMS affecting the oral cavity and gnathic bones were retrieved. Clinical and demographic data were obtained from the patients' pathology records, while microscopic features and immunohistochemistry were reviewed and completed when necessary to confirm the diagnoses. Twenty-two LMs and five LMSs were obtained. In the LM group, males predominated, with a mean age of 45.7 years. The upper lip was the most affected site, and 18 cases were classified as angioleiomyomas and four as solid LM. In the LMS group, females predominated, with a mean age of 47.6 years. The mandible was the most affected site. Diffuse proliferation of spindle cells, with necrosis and mitotic figures, were frequent microscopic findings. LMs and LMSs were positive for α-smooth muscle actin, HHF-35 and h-caldesmon. In conclusion, oral LM/LMS are uncommon neoplasms with the latter usually presenting as metastatic disease. H&E evaluation may be very suggestive of oral LMs, but h-caldesmon staining is strongly recommended to confirm LMS diagnosis. [ABSTRACT FROM AUTHOR]

The oral lymphoepithelial cyst (OLC) is an uncommon lesion whose pathogenesis remains poorly understood. The aim of this study was to report the clinicopathologic features of the OLCs and to verify a possible association between OLCs and subgemmal neurogenous plaque (SNP) in the posterior lateral region of the tongue. A retrospective descriptive cross-sectional study was carried out. A total of 106,282 biopsy records of oral and maxillofacial lesions from six oral pathology services in Brazil were analyzed. All cases of OLCs were reviewed, and clinical and histopathological data were collected. Immunohistochemical reactions for S-100 protein were performed to confirm the diagnosis of SNP. Among all lesions, there were 132 (0.11%) cases of OLCs. The series comprised 83 females (62.9%) and 49 males (37.1%), with a 1.7:1 female-to-male ratio and a mean age of 45.8 ± 17.7 years. Most cases involved the tongue (n = 80; 62.0%) and presented clinically as asymptomatic papules or nodules with a yellow or whitish color. Microscopically, most of the cysts were entirely lined by parakeratinized stratified epithelium (n = 89; 67.4%) and filled with desquamated cells, keratin debris, amorphous eosinophilic material, and inflammatory cells in varying amounts. Connection with the epithelium of oral mucosa was observed in 18 cases (13.6%). SNP was found in 9/80 (11.2%) cases involving the tongue. The clinical and demographic features of OLCs were similar to those described in previous studies. Overall, this lesion has a predilection for the posterior region of the tongue of female adults. Clinicians must include the OLC in the differential diagnosis of yellow/white papules and nodules of the oral cavity. [ABSTRACT FROM AUTHOR]

Liposarcomas of the oral cavity are rare. Those originating in the buccal mucosa cause challenging diagnostic and therapeutic issues since less than 40 cases of liposarcomas of the buccal mucosa and cheek have been reported in the worldwide literature. Herein, we present a case of atypical lipomatous tumor/well-differentiated liposarcoma affecting a 45-year-old female patient. Ultrasonography and magnetic resonance imaging confirmed a well-defined mass located in the right buccal mucosa, extending to the submucosal layers of the cheek. Histopathologically, a well-differentiated fatty neoplasm with presence of prominent stromal inflammatory cells was observed. Multifocally scattered bizarre hyperchromatic stromal cells, some of which multinucleated, were also observed. An immunohistochemical panel comprising vimentin, S-100, CD10, CD34, CD20, CD3, CD68, CD138, MDM2, Ki-67, and P53 was employed to better characterize the lesion. A local recurrence event occurred during a 10-year follow-up period. Surgical resection was performed during both episodes. We also provided an overview of demographic and clinicopathological characteristics, immunohistochemical features, imaging findings, and the differential diagnosis of liposarcoma of the oral cavity. Knowledge of the etiopathological and clinical aspects of this rare neoplasm is fundamental in order to rule out other conditions, including lipomatous lesions that affect the buccal mucosa. [ABSTRACT FROM AUTHOR]

To compare two grading systems of epithelial dysplasia—World Health Organization (WHO) and binary system (BS) –in actinic cheilitis (AC). Seventy cases diagnosed as AC in an Oral Pathology Laboratory from Brazil in the last 12 years were retrospectively retrieved, including the demographic data of each patient. All conventionally stained slides were reviewed, and epithelial dysplasia was evaluated by two independent observers using both WHO and BS grading systems. Data correlation was performed using kappa and chi-square tests (p < 0.05). Most patients were white men with a mean age of 57 years old and history of chronic exposure to sunlight. Most of the lesions were clinically described as whitish plaques with irregular surface located in the lower lip semi-mucosa. Most cases were microscopically graded as severe epithelial dysplasia and low-risk by both observers. The interobserver and intraobserver agreement between systems was slight. All reddish lesions were graded as severe epithelial dysplasia, showing an equal distribution between low and high-risk grading. Most ulcerated lesions showed severe epithelial dysplasia but was graded as low-risk of malignant transformation. Statistical significance was observed among the presence of "irregular stratification", severe epithelial dysplasia and high-risk lesions (p < 0.05) likewise among the presence of "loss of polarity of basal cells" and "drop-shaped ridges" (p < 0.05) with high-risk lesions. The absence of "increased mitotic figures", "dyskeratosis" and "keratin pearls" (p < 0.05) were strongly correlated to low-risk lesions. The presence of "hyperchromasia" was statistically significant with severe epithelial dysplasia (p < 0.05) as well the absence of "atypical mitotic figures" with low-risk lesions (p < 0.05). Although there was slight agreement between microscopic grading systems, microscopic analysis indicated that architectural epithelial changes individually may be the more reliable criteria to indicate the risk of malignant transformation in AC in both grading systems. [ABSTRACT FROM AUTHOR]

Myofibroma (MF) is a benign mesenchymal myofibroblast-derived tumor, which occurs most frequently in children, and rarely affects the maxilla. We reported a case of an aggressive intraosseous lesion found in the maxilla of a 9-year-old female child. Intraorally, the swelling extended from tooth 12 to 16, causing displacement of teeth 13, 14, and 15. Computed tomography revealed a large osteolytic lesion causing thinning and cortical erosion. Microscopically, the lesion showed a proliferation of spindle-shaped cells, with elongated nuclei and eosinophilic cytoplasm, arranged in interlaced fascicles. The immunohistochemical analysis revealed cytoplasmic positivity for α-SMA and HHF-35, and negativity for desmin, laminin, S-100, β-catenin, and CD34. Ki-67 was positive in 8% of tumor cells. The diagnosis was MF. Herein, we describe an additional case of central MF arising in the maxilla, including clinical, imaging, microscopical, and immunohistochemical features, as well as a review of the literature. [ABSTRACT FROM AUTHOR]

The aim of this study was to describe the clinicopathological and immunohistochemical features of four cases of anaplastic large cell lymphoma (ALCL) diagnosed through oral manifestations. Clinical data were collected from charts of a single oral pathology laboratory over a 5-year period (2014–2019) and all cases were evaluated by conventional hematoxylin and eosin staining and an extended immunohistochemical panel comprising CD45, CD20, CD3, CD4, CD7, CD30, CD99, CD138, cytokeratin AE1/AE3, EMA, ALK, MUM-1 and Ki-67. The study included 3 male (75%) and 1 female (25%) patients, with a median age of 44 years. The most common intraoral affected site was the alveolar ridge (50%). Clinically, all cases were characterized as an ulcerated bleeding mass. Microscopically, proliferation of anaplastic large lymphoid cells with medium to large-sized, abundant amphophilic to eosinophilic cytoplasm and eccentric nuclei were observed. All cases were positive for CD30, while two cases strongly express ALK. Two patients died of the disease. Careful correlation of clinical, morphological and immunohistochemical data are necessary to establish the diagnosis of oral manifestation of ALCL since its microscopical features may mimic other malignant tumors. Clinicians and pathologists should consider ALCL in the differential diagnosis when evaluating oral ulcerated swellings exhibiting large lymphoid cells in patients with lymphadenopathy. [ABSTRACT FROM AUTHOR]

Data on the occurrence and clinicopathological characteristics of actinic cheilitis (AC) and lip squamous cell carcinoma (LSCC) are well studied; however, they are based on studies limited to a single centre. Herein, we described the frequency of AC and LSCC submitted to microscopic examination from representative geographic regions of Brazil. A retrospective multicentre study was performed on biopsies obtained from 1953 to 2018 at 10 Brazilian oral and maxillofacial pathology centres. A total of 198,709 biopsy specimens were surveyed. Sociodemographic data and clinicopathologic characteristics were analysed. A total of 2017 cases of ACs (1.0%) and 850 cases of LSCCs (0.4%) were recorded. A strong fair-skinned (> 87%) male (> 70%) predilection was observed in both conditions. The mean age was 54.8 ± 18.7 for individuals with AC and 57.8 ± 19.0 for individuals with LSCC. The most commonly affected site was the lower lip (> 90%). This is a large multicentre study of AC and LSCC from Brazil. The frequency and clinicopathological features of AC and LSCC were similar to those described worldwide. This study provides robust and representative epidemiological data of these conditions for the scientific community. [ABSTRACT FROM AUTHOR]

Primordial odontogenic tumor (POT) was recently recognized in the 2017 World Health Organization (WHO) Classification as a distinct mixed odontogenic tumor most commonly observed in the posterior mandible of young patients. POT appears as an expansile radiolucency associated to an unerupted tooth. The aim of the present study was to perform a retrospective microscopic evaluation of pediatric odontogenic tumors diagnosed in an Oral Pathology Laboratory from Rio de Janeiro—Brazil, in order to reclassify potential cases as POT. From 150 cases of odontogenic tumors in children diagnosed in the last 50 years, one case filled the criteria for POT, being therefore better diagnosed as such. The patient was in the first decade of life and presented a well-defined expansile tumor in the posterior mandible, which had been initially diagnosed as immature complex odontoma. To the best of our knowledge, only 12 cases of POT have been reported in the English-language literature. We herein present an additional case of POT and review of its clinicopathological findings is offered. [ABSTRACT FROM AUTHOR]

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplastic proliferation with variable clinical behavior caused by the accumulation of CD1a+/CD207+ histiocytes, associated with a variable number of eosinophils, lymphocytes, plasma cells and multinucleated giant cells, most commonly observed in male children. LCH is uncommon in the head and neck region, occurring as ulcerated and reddened plaques or nodules that cause destruction of adjacent soft tissues and bone. The exact etiology of LCH is still unknown and controversial, with possible etiologic role of viruses, including Epstein-Barr virus (EBV). The aim of this study was to describe the clinicopathologic and immunohistochemical features of patients with LCH of the head and neck region. Clinical data from 19 patients with LCH were obtained from the archives of the Federal University of Rio de Janeiro and the Clinical Head and Neck Center of Guatemala. All cases were submitted to morphological, immunohistochemical analysis with CD1a, CD207, CD3, CD20, CD68, S-100 and Ki-67 and in situ hybridization for EBV. Ten cases were female and 9 male, with mean age of 11.5 years. Fourteen cases were located in the oral cavity, three cases in lymph nodes, and two cases in the scalp. In regard to the oral lesions, 13 cases were intra-osseous with six cases in anterior mandible, five cases in posterior mandible, and two cases in posterior maxilla while one case was located exclusively in the gingiva. The inflammatory pattern showed variation in the number of plasma cells, eosinophils and lymphocytes, while tumor cells were positive for CD1a, S-100 and CD68 in all cases, and positive for CD207 in 18 cases. In situ hybridization for EBV were negative in all cases. [ABSTRACT FROM AUTHOR]