Mucoepidermoid carcinoma of the palate mimicking a pyogenic granuloma in a 30-year-old woman.

Mucoepidermoid carcinoma (MEC) is the most common salivary gland adenocarcinoma, more frequently affecting female patients in the fifth decade of life. When MEC arises in the minor salivary glands, the palate is the primary site. This case report describes an MEC on the palate of a 30-year-old woman. The lesion was initially treated as a pyogenic granuloma, but the final diagnosis based on histopathology was low-grade MEC. The patient was referred for cancer treatment, and no recurrence was observed during 3 years of follow-up. Some malignant tumors can mimic nonneoplastic reactive lesions clinically, which highlights the importance of biopsy and proper microscopic analysis of the resulting specimens.

Actinomycotic Osteomyelitis and Myiasis in Oroantral Communication: Clinicopathological and Tomographic Findings

Actinomycotic osteomyelitis of the maxilla presenting with oroantral communication is very rare, herein we report the first case of this condition in association with myiasis. A 50-year-old man reported chronic sinusopathy and a non-healing maxillary lesion, with 30 years of evolution, presenting occasional nasal and intraoral purulent discharge, with foul smell, and recurrent episodes of larvae presence. Cone beam computed tomography showed a large hyperdense image inside the left maxillary sinus, with focal areas with soft tissue density, and extensive discontinuity of the maxillary sinus floor, confirming the oroantral fistula. The necrotic tissue curetted during surgery presented hard consistency, and dark greenish color, and was submitted for histopathological analysis. Microscopically, necrotic bone, masses of filamentous bacteria colonie s, compatible with actinomycosis, and large rhomboidal structures surrounded by eosinophilic capsule - suggestive of larvae, were observed. The diagnosis of actinomycotic osteomyelitis with presence of structures compatible with larvae was established.

La osteomielitis actinomicótica del maxilar que se presenta con comunicación oroantral es poco frequente. En este trabajo reportamos el primer caso de esta condición en asociación con miasis. Un hombre de 50 años que refiere sinusopatía crónica y lesión maxilar que no cicatriza, de 30 años de evolución, presenta secreción ocasional purulenta nasal e intraoral, con mal olor y episodios recurrentes de presencia de larvas. La tomografía computarizada de haz cónico mostró una gran imagen hiperdensa en el interior del seno maxilar izquierdo, con áreas focales con densidad de partes blandas y una extensa discontinuidad del piso del seno maxilar, lo que confirma la fístula oroantral. El tejido necrótico legrado durante la cirugía presentó consistencia dura, coloración verdosa oscura, y fue remitido para análisis histopatológico. Microscópicamente se observó hueso necrótico, masas de colonias de bacterias filamentosas compatibles con actinomicosis y grandes estructuras romboidales rodeadas de cápsula eosinofílica sugestiva de larvas. Se estableció el diagnóstico de osteomielitis actinomicótica con presencia de estructuras compatibles con larvas.

Oral epithelioid rhabdomyosarcoma: Report of a rare case and literature review of a distinct variant of rhabdomyosarcoma.

Epithelioid rhabdomyosarcoma is a new and rare morphological variant of rhabdomyosarcoma, with only a few reports in the literature. We aimed to describe an atypical case of this variant involving the oral cavity. A 33-year-old male patient presented with an asymptomatic, gingival mass adjacent to the left maxillary canine with progressive growth over approximately 3 months. Microscopic and immunohistochemical assessment of the biopsy specimen were consistent with epithelioid rhabdomyosarcoma. After initial chemotherapy and radiotherapy, the patient had a partial response. Surgical resection was performed, followed by adjuvant chemotherapy. After local and distant recurrences, the patient died 22 months after the initial diagnosis. According to the literature, epithelioid rhabdomyosarcoma still lacks data regarding its aetiologic factors and therapeutic options. Whether this tumour is a true subtype or simply a variant of other subtypes of rhabdomyosarcoma also remains unconfirmed. Final diagnosis leads to a broad array of microscopic and immunohistochemical analyses.

Comparison of orosomucoid-1 immunoexpression and angiogenesis between oral squamous cell carcinoma cases with different histological grades.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is the most common malignancy in this region, and thus, further elucidation of its tumoral mechanisms is important. One of the main roles of the acute-phase protein orosomucoid-1 (ORM1) is the promotion of angiogenesis, which is key for tumor nutrition and growth. AIM: Our aim was to evaluate the immunohistochemical expression of ORM1 and the angiogenic activity indicated by microvascular density (MVD) in OSCC samples according to histological grade. MATERIALS AND METHODS: Formalin-fixed, paraffin-embedded sections from 45 OSCC cases were submitted to immunohistochemistry: 25 were well-differentiated OSCC, 18 were moderately differentiated OSCC and 2 were poorly differentiated OSCC. ORM1 staining was evaluated by a semiquantitative method, and CD34-positive blood vessels were quantified to calculate the MVD. The results were statically analyzed. RESULTS: All cases exhibited immunoexpression of ORM1 and CD34. However, no significant differences were found between the expression of both markers among the histological grades. In addition, the presence of ORM1 in inflammatory cells and in the extracellular matrix was detected in most cases. CONCLUSION: These results suggest that the induction of angiogenesis is not the main role of ORM1 in OSCC and may be associated with the regulation of the immune/inflammatory response or the transport of protumoral molecules, such as sialyl-Lewis X or phorbol esters, which requires confirmation in future studies.

Mature T/NK-Cell lymphomas of the oral and maxillofacial region: A multi-institutional collaborative study.

BACKGROUND: The diagnosis of oral and maxillofacial mature T/NK-cell neoplasms is challenging because of their rarity, morphological heterogeneity and complex immunophenotype with scarce available data describing their clinical and microscopic aspects. Therefore, in this study, we investigated a series of mature T/NK-cell neoplasms affecting this anatomical region and provided an updated literature review. METHODS: Cases diagnosed as mature T/NK-cell lymphomas affecting the oral and maxillofacial region were retrospectively retrieved from six pathology files and their diagnoses were confirmed using haematoxylin and eosin-stained slides, immunohistochemical reactions and in situ hybridization for Epstein-Barr virus (EBV) detection. Patients' clinical data were collected from their pathology forms. RESULTS: A total of 22 cases were included in this study. Eleven (50%) consisted of extranodal NK/T-cell lymphomas, nasal type; eight (36.4%) were peripheral T-cell lymphomas, NOS; two (9.1%) were adult T-cell leukaemia/lymphomas, and one (4.5%) was an ALK-positive anaplastic large cell lymphoma. Overall, males predominated, with a mean age of 55.7 years. The palate was the most affected site (50%), and tumours usually presented as destructive and painful ulcers. EBV was present in all cases of extranodal NK/T-cell lymphoma nasal type but was absent in the other subtypes. CONCLUSION: Among mature T/NK-cell lymphomas of the oral and maxillofacial region, extranodal NK/T-cell lymphoma, nasal type and peripheral T-cell lymphoma, NOS predominated. Older men were the most affected patients, and this heterogeneous group of neoplasms has a very aggressive clinical behaviour.

Perilipin 1 and adipophilin immunoexpression suggests the presence of lipid droplets in tooth germ, ameloblastoma, and ameloblastic carcinoma.

BACKGROUND: Increased lipogenesis and lipid droplet accumulation are observed in diverse tumors, and these processes are associated with poor prognosis in several tumors, representing potential therapeutic targets. The presence of lipid droplets in odontogenic tissues and/or tumors is unknown. METHODS: Immunohistochemistry for perilipin 1 and adipophilin was performed in 12 human tooth germs (TG), 27 conventional ameloblastoma (AM), and 8 ameloblastic carcinoma (AC) samples. Cytoplasmic staining was analyzed using an immunoreactive score (IRS), and the results were compared for the TG, AM, and AC samples by Kruskal-Wallis test followed by Dunn's post-test and confirmed by Mann-Whitney U test. RESULTS: Perilipin 1 was negative in 91.7% of the TG samples, positive in 48.2% of the AM samples, and positive in 87.5% of the AC samples. Adipophilin was positive in 100% of the TG samples, 92.6% of the AM samples, and 100% of the AC samples. The perilipin 1 and adipophilin IRS revealed statistically significant differences between the TG, AM, and AC samples (p = .007 and p = .018, respectively). The perilipin 1 levels among the TG and AC samples were statically significant (**p = .0085), as well as the adipophilin levels when TG and AM samples were compared (**p < .0029). CONCLUSIONS: Adipophilin exhibits significant activity in human tooth development. The immunoexpression of perilipin 1 and adipophilin in the AM and AC samples suggests the presence of lipid droplets, providing further evidence of metabolic alterations in these tumors. Additional studies with larger samples and alternative techniques are necessary to confirm these findings.

Kaposiform Hemangioendothelioma of the Oral Cavity: A Rare Tumor with an Unusual Location.

Kaposiform hemangioendothelioma is a rare neoplasm with intermediate malignant behavior, mainly affecting infants and children. Involvement head and neck is uncommon, and there are only four cases reported in the oral cavity and oropharynx. Microscopically, it is characterized by a vascular proliferation permeated by spindle-to-ovoid cells resembling Kaposi sarcoma. Immunohistochemically, the tumor is positive for CD31, CD34 and negative for D2-40. Herein we present a rare case of intraoral Kaposiform hemangioendothelioma in a 10-year-old boy.

Extranodal NK/T cell lymphoma, nasal type: An updated overview.

Extranodal NK/T-cell lymphoma, nasal type (ENKTCL-NT) is an aggressive malignancy associated with Epstein-Barr virus infection, with a geographic and racial predilection for some Asian and Latin American countries. ENKTCL-NT manifests as a necrotic process affecting nasal or upper aerodigestive structures and, rarely, extranasal sites such as skin, and the gastrointestinal tract. ENKTCL-NT was characterized by its poor prognosis irrespective of clinical stage and therapy. However, during the last two decades, advances in its clinicopathologic, genetic and molecular characterization have been achieved, as have changes in the chemotherapy regimens that, in combination with radiotherapy, are significantly improving the survival of these patients, especially in initial stages. For these reasons, we present an overview of the historical background of ENKTCL-NT along with an updated review of its potential etiological factors, clinicopathologic and molecular features, as well as its prognostic models, current treatment protocols, and future directions on potential promising therapeutic approaches.

Mixed odontogenic tumors: A review of the clinicopathological and molecular features and changes in the WHO classification.

BACKGROUND: Ameloblastic fibromas and ameloblastic fibrosarcomas are rare odontogenic tumors, and controversy exists in the classification of cases presenting hard-tissue production: Ameloblastic fibrodentinoma (AFD) and ameloblastic fibro-odontoma (AFO). These cases are currently considered "developing odontomas" (hamartomatous lesions). AIM: To analyze the clinicopathologic features of these lesions and discuss the changes in the 2017 World Health Organization classification. METHODS: An electronic literature search was performed in the PubMed/MEDLINE database. An electronic search of the English language literature was performed and last updated in September 2020 in the PubMed/MEDLINE database using the following terms: "ameloblastic fibroma", "ameloblastic fibrodentinoma", "ameloblastic fibro-odontoma", "ameloblastic sarcoma", "ameloblastic fibrosarcoma", "ameloblastic fibrodentinosarcoma", "ameloblastic fibroodontosarcoma" and "odontogenic carcinosarcoma". The inclusion criteria were odontogenic tumor series, case reports and systematic reviews that provided sufficient clinical, radiological and microscopic documentation to confirm the diagnosis. RESULTS: The database search strategy resulted in 947 papers. Articles focusing on other topics, articles that were not in English, duplicate articles, and articles without fulfilling the inclusion criteria were excluded. Finally, 96 publications were included in this review to describe and discuss the main features of the searched entities. Several aspects of AFO and AFD, such as biological behavior, age of occurrence, amount of hard tissue, and potential for malignant transformation into odontogenic sarcomas, support the neoplastic nature in most of the reported cases. Considering the clinical, radiographic, histopathological and molecular characteristics of odontogenic lesions with hard tissue production, we suggest that these types of lesions should continue to be recognized as odontogenic tumors by maintaining the classically used terms. CONCLUSION: This recommendation will be relevant for future clinical, microscopic, and molecular studies to better understand the biology of these interesting odontogenic tumors.

Aggressive Intraosseous Myofibroma of the Maxilla: Report of a Rare Case and Literature Review.

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, ß-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.

BDNF/TrkB/Akt Signaling Pathway Epithelial Odontogenic Tumors and Keratocyst: An Immunohistochemical Study Comparative With Dental Germs.

Odontogenic lesions (OL) are an important group of oral and maxillofacial diseases represented by odontogenic cysts, benign, and malignant tumors. The brain-derived neurotrophic factor (BDNF)/ tropomyosin receptor kinase B (TrkB) signaling pathway has multiple biological actions and has been identified as an important pathway in the proliferation, invasion, and survival of different epithelial tumors. Its role in the development of OL, however, has so far been unexplored. Our aim was to evaluate the BDNF/TrkB/Akt/p-RPS6 signaling pathway in OL of epithelial origin. This cross-sectional study comprised 3 cases of tooth germs, 25 cases of odontogenic keratocyst (OK), 29 cases of ameloblastoma (Am), and 6 cases of ameloblastic carcinoma. Immunohistochemical staining for BDNF, TrkB, p-Akt, and p-RPS6 was performed. OLs were evaluated according to the pattern of immunohistochemical expression in epithelial cells and by semiquantitative scores that considered the intensity of staining and percentage of positive cells. BDNF stromal expression was also assessed. No significant differences were observed with respect to the percentage of positive cases for all markers. Regarding the immunoreactive scores, BDNF and p-RPS6 expressions were similar in the odontogenic epithelium of all OL. However, TrkB and p-Akt were overexpressed in OK compared with ameloblastic carcinoma. In Am, epithelial BDNF was significantly higher compared with stromal expression. In conclusion, BDNF seems to participate in the development of cystic, benign, and malignant odontogenic epithelium to similar degrees. The acquisition of the invasive or malignant phenotype in odontogenic neoplasms is not associated with alterations in the BDNF/TrkB/Akt/RPS6 axis, which could be implicated in the differentiation process.

Spindle cell carcinoma of the maxillary sinus with extension to the oral cavity.

Spindle cell carcinoma (SCC) is a rare variant of squamous cell carcinoma characterized by elongated and pleomorphic epithelial cells that resemble a sarcoma. Due to its rareness, and histological resemblance to various sarcomas, the diagnosis of this neoplasia is challenging. Herein we present the case of an 82-year-old female with a polypoid, ulcerated, soft tissue mass located on the left side of the maxilla. The tomographic examination showed a hyperdense mass that infiltrated the orbital cavity, ethmoidal cells, middle and lower nasal concha, maxillary sinus, zygomatic arch, and mandibular ramus on the left side. Histopathologically, the tumor was composed of spindle cells that were sarcomatous in appearance, with aberrant mitosis, along with a group of pleomorphic cells with a more epithelioid and hyperchromatic appearance on a stroma of densely vascularized fibrous tissue. The immunohistochemistry panel used to determine the lineage of the tumor rendered the diagnosis of SCC. The diagnosis of SCC is challenging to the pathologist since its morphology can resemble a sarcoma. Thus, immunohistochemistry is a valuable resource to support the diagnosis. We propose that SCC should be considered when examining a biphasic neoplasm with the aforementioned histological characteristics and markers.

Gingival squamous cell carcinoma mimicking a non-neoplastic proliferative lesion in an older patient.

OBJECTIVE: To report a case of gingival squamous cell carcinoma (SCC) in an elderly patient mimicking a non-neoplastic proliferative lesion. BACKGROUND: Oral SCC is a well-recognised malignancy of the oral cavity that may mimic benign reactive proliferative processes. METHODS: An excisional biopsy was performed, and the diagnosis was gingival SCC. CONCLUSION: It is essential that both the clinician and pathologist to be aware of such a presentation to allow for proper diagnosis and treatment.

Perfil inmunohistoquímico del mixoma odontogénico, con énfasis en marcadores de agresividad tumoral y microdensidad vascular / Perfil imuno-histoquímico do mixoma odontogênico, com ênfase em marcadores de agressividade tumoral e microdensidade vascular / Immunohistochemical profile of odontogenic myxoma, with a focus on microvascular density and tumor aggressiveness markers

Con el fin de tener una mayor comprensión sobre el comportamiento biológico del mixoma odontogénico (MO), se realizó inmunohistoquímica en 31 muestras, utilizando marcadores relacionados con mecanismos de progresión tumoral (adhesión, angiogénesis, apoptosis, inflamación y proliferación celular). El epitelio odontogénico fue detectado en cuatro muestras mediante CK19 y CD138, este último, mostró expresión baja en matriz extracelular (MEC) y alta en las células tumorales. La microdensidad vascular (MDV) media fue de 7.51 y 5.35 vasos marcados con CD34 y VEGF-A respectivamente. Una alta expresión de Orosomucoide-1 y Mast Cell Tryptase se observó células tumorales y en MEC. El MO mostró negatividad para Calretinina. Este perfil inmunohistoquímico, la baja expresión para Ki-67, Bcl-2 y p53, y la relativamente baja MDV, sugieren que la actividad proliferativa, anti-apoptótica o angiogénica no representan los principales mecanismos de crecimiento del MO, los cuales podrían estar asociados a eventos como inmunomodulación y degradación de la MEC.

Immunohistochemistry tests were performed in 31 samples to elucidate the biological behavior of the odontogenic myxoma (OM), using markers related to mechanisms of tumor progression (adhesion, angiogenesis, apoptosis, inflammation and cell proliferation). Odontogenic epithelium was detected in four samples with CK19 and CD138; the latter had a low expression in the extracellular matrix (ECM) and a high expression in tumor cells. The mean microvascular density (MVD), assessed with CD34 and VEGF-A, was 7.51 and 5.35 blood vessels. A high expression of orosomucoid-1 and mast cell tryptase was observed in tumor cells and ECM, while calretinin was negative. The immunohistochemical profile mentioned above, as well as the low expression of Ki67, Bcl-2 and p53 and the relatively low MVD, suggest that the proliferative, antiapoptotic and angiogenic activities do not represent the main growing mechanisms of OM, which could be associated to other events, such as immunomodulation and ECM degradation.

Para melhor compreensão do comportamento biológico do mixoma odontogênico (MO), imuno-histoquímica foi realizada em 31 amostras, utilizando marcadores relacionados aos mecanismos de progressão tumoral (adesão, angiogênese, apoptose, inflamação e proliferação celular). Epitélio odontogênico foi detectado em quatro amostras por CK19 e CD138, o último mostrou baixa expressão na matriz extracelular (MEC) e alta em células tumorais. A microdensidade vascular (MDV) média foi de 7.51 e 5.35 vasos marcados com CD34 e VEGF-A, respectivamente. Uma alta expressão de Orosomucoide-1 e Mast Cell Tryptase foi observada nas células tumorais e na MEC. O MO mostrou negatividade para Calretinina. O perfil imuno-histoquímico mencionado acima, a baixa expressão de Ki-67, Bcl-2 e p53 e a relativamente baixa MDV, sugerem que a atividade proliferativa, anti-apoptótica ou angiogênica não representam os principais mecanismos de crescimento do MO, os quais poderiam estar associados com eventos como imunomodulação e degradação da MEC.

Generalized hereditary gingival fibromatosis in a child: clinical, histopathological and therapeutic aspects

Hereditary gingival fibromatosis (HGF) is a rare genetic condition characterized by slow and progressive gingival enlargement. The gingival overgrowth often delays teeth eruption and may cause serious functional and aesthetic problems. We reported a case of a 10-year-old female child presenting a generalized gingival enlargement covering almost all the maxillary and mandibular teeth and resulted in problems for swallowing, speaking, and poor aesthetics. An incisional biopsy was performed and revealed a hypocellular and hypovascular dense collagenous tissue covered by squamous epithelium exhibiting acanthosis and elongated rete ridges. The diagnosis was HGF. The treatment instituted was an association of gingivectomy with a rigorous program of oral hygiene and follow-up. Herein, we describe a rare non-syndromic case of generalized HGF, including clinical and microscopical features, as well as highlighting the importance of correct diagnosis of this genetic condition.

Generalized hereditary gingival fibromatosis in a child: clinical, histopathological and therapeutic aspects.

Hereditary gingival fibromatosis (HGF) is a rare genetic condition characterized by slow and progressive gingival enlargement. The gingival overgrowth often delays teeth eruption and may cause serious functional and aesthetic problems. We reported a case of a 10-year-old female child presenting a generalized gingival enlargement covering almost all the maxillary and mandibular teeth and resulted in problems for swallowing, speaking, and poor aesthetics. An incisional biopsy was performed and revealed a hypocellular and hypovascular dense collagenous tissue covered by squamous epithelium exhibiting acanthosis and elongated rete ridges. The diagnosis was HGF. The treatment instituted was an association of gingivectomy with a rigorous program of oral hygiene and follow-up. Herein, we describe a rare non-syndromic case of generalized HGF, including clinical and microscopical features, as well as highlighting the importance of correct diagnosis of this genetic condition.

Primary maxillary chondrosarcoma: A case report.

BACKGROUND: Sarcomas of the head and neck region are rare tumors, constituting less than 1% of malignant neoplasms in this area, of which few cases (20%) originate from bone or cartilage. Chondrosarcoma is a malignant neoplasm that develops in bone, with a predilection for the pelvis, chest wall, and scapula, and is uncommon in the maxilla and jaw. Although this type of lesion has locally aggressive behavior, destroying the affected bone, it can metastasize when it is not diagnosed early and compromise the patient's life. CASE SUMMARY: On intraoral examination of a 32-year-old female with a tumor in the middle third of the face, a well-defined rise in volume of approximately 3 cm in diameter was observed. Computed tomography with 3-dimensional reconstruction was performed, and we observed that the osteolytic lesion affected the vestibular cortex as the palatal bone. Hematoxylin and eosin staining revealed an appearance that was similar to mature hyaline cartilage, hypercellularity, nuclear and cellular pleomorphism, and multinucleated cells, with significant vacuolization. CONCLUSION: Determination of the clinical and histopathological characteristics of rare neoplasms in the maxillofacial region, such as chondrosarcomas, allows the pathologist and surgeon to make the appropriate therapeutic decisions, optimizing the patient's prognosis.

Hyalinizing clear cell carcinoma-a rare entity in the oral cavity: A case report.

BACKGROUND: Hyalinizing clear cell carcinoma (HCCC) is an uncommon tumor that originates in the salivary glands. This neoplasia constitutes less than 1% of minor salivary gland tumors. CASE SUMMARY: A 67-year-old female visited the maxillofacial surgery department owing to a smooth, slightly yellowish protruding mass on the left side of the floor of the mouth, at the level of the molars; the tumor mass had a soft consistency on palpation and did not adhere to deep planes. The microscopical analysis of the excisional biopsy showed that the lesion was composed of sheets and cords of clear cells separated by thick eosinophilic bands of hyaline collagen. Normal glandular tissue was absent, periodic acid-Schiff with and without diastase stains, and immunohistochemical reactions were performed to confirm the diagnosis. This is the second case reported in the literature of HCCC arising in the floor of the mouth. CONCLUSION: HCCC is a rare salivary gland tumor that has not been studied extensively. Its diagnosis is usually challenging, because clinically, it can be confused with a benign neoplasm.

Respiratory scleroma: A clinicopathologic study of 51 cases from Guatemala.

OBJECTIVES: To evaluate clinical and pathologically cases of respiratory scleroma diagnosed in a 30-year period in Guatemala. MATERIAL AND METHODS: Fifty-one cases of respiratory scleroma diagnosed from 1988 to 2018 in a single pathology service in Guatemala were confirmed using Warthin-Starry staining. Immunohistochemical reactions against CD68, LCA, CD20, CD3, and CD138 were performed to illustrate the inflammatory infiltrate. Scanning electron microscopy (SEM) was performed to illustrate bacteria morphology. RESULTS: All 51 cases affected patients from poor areas of Guatemala, particularly women (66.7%), with a mean age of 31 years (range 7-66 years). Nose was affected in most cases (96.1%). Other sites involved included pharynx, larynx, palate, maxillary sinuses, and upper lip. Depending on the stage, the disease manifested as ulcerations, nasal deformities, or laryngeal stenosis. Nasal obstruction, epistaxis, dysphonia, fetid discharge, and pain were the main symptoms. Mikulicz cells (CD68+) in a plasma cell-rich inflammatory background (CD138+, CD20+, CD3+/-) were the typical microscopic presentation. In SEM, each macrophagic vacuole contained few to dozens of Klebsiella rhinoscleromatis diplobacilli. Treatment consisted of long-term trimethoprim and sulfamethoxazole, with adequate control of disease. CONCLUSION: Respiratory scleroma is a rare infectious disease affecting the upper respiratory tract, in poor regions of the world, including Guatemala.