ABSTRACT: An aneurysm is defined as a localized dilation of a blood vessel or heart. It may have either a congenital or an acquired origin and occurs in both humans and animals. Cardiac aneurysms are rare, and are characterized by sacculations of the cardiac wall. The present case report describes the macroscopic and microscopic findings of an aneurysm affecting both ventricles of the heart in a dog. A 7-year-old mixed-breed female dog with osteosarcoma on the left pelvic limb was euthanized and submitted to the veterinary pathology laboratory for necropsy. Macroscopically, besides the lesions in the link, the pericardial sac was adhered to the pericardial surface of the heart and there were two sacculations in both ventricles which communicated widely with the respective ventricle. Microscopically, fibrous tissue adhered to the pericardium, atrophy and necrosis of the cardiomyocytes with replacement by adipocytes were observed in addition to hyperplasia of the tunica media of arterioles and thrombosis. A diagnosis of acquired biventricular cardiac aneurysm was made based on the necropsy findings and microscopic lesions in the heart. We emphasize the importance of performing a necropsy and examining tissues histologically for the diagnosis of this rare condition. Ventricular aneurysms should be included in the differential diagnosis of cardiovascular disease in dogs.

RESUMO: O aneurisma é uma dilatação localizada em um vaso sanguíneo ou no coração. Pode ter origem congênita ou adquirida e ocorre tanto em humanos quanto em animais. Os aneurismas cardíacos são raros e caracterizados por saculações da parede cardíaca. O presente relato de caso descreve os achados macro e microscópicos de um aneurisma no coração de um cão, que afetava ambos os ventrículos. Uma cadela com sete anos de idade, diagnosticada com osteosarcoma, foi submetida a eutanásia e encaminhada ao laboratório de patologia veterinária para necropsia. Macroscopicamente, além da lesão neoplásica no membro pélvico esquerdo, o saco pericárdico estava aderido à superfície pericárdica do coração e havia duas saculações em ambos os ventrículos que se comunicavam amplamente com o respectivo ventrículo. Microscopicamente, observou-se tecido fibroso aderido ao pericárdio, atrofia e necrose dos cardiomiócitos com substituição por adipócitos, além de hiperplasia da túnica média das arteríolas e trombose. O diagnóstico de aneurisma cardíaco biventricular adquirido foi feito com base nos achados de necropsia e lesões microscópicas no coração. Ressaltamos a importância da necropsia e exame histológico para o diagnóstico dessa rara condição. Os aneurismas ventriculares devem ser incluídos no diagnóstico diferencial de doenças cardiovasculares em cães.

BACKGROUND: Osteosarcoma is a malignant tumour that typically originates in long bones. We present a case of a subject afflicted by osteosarcoma in the left shoulder, an extremely uncommon location. CASE REPORT: The subject, a 14-year-old adolescent, presented with a manifestation of osteosarcoma in an atypical location, namely the left shoulder. Radiographic analysis, including scapula plain radiograph, identified a radiodense lesion. Subsequent computed tomography disclosed compromised cortical integrity without medullary tissue involvement. Histological verification confirmed osteosarcoma. The absence of a commercially available suitably sized endoprosthesis for this unique anatomical location prompted the innovative use of a 3D-printed version based on the dimensions of the unaffected right shoulder. Post scapulectomy, a hernia mesh was employed for glenoid capsule reconstruction, ensuring subluxation prevention and yielding excellent postoperative outcomes. DISCUSSION: This case underscores the complexities and innovations in osteosarcoma treatment when occurring in unconventional anatomical sites, exemplified by its manifestation in the scapula. The integration of 3D-printing technology emerges as a promising avenue for tailoring solutions in orthopaedic oncology, particularly addressing the constraints posed by the absence of commercially available devices for rare anatomical locations. CONCLUSION: Managing scapular osteosarcoma necessitates innovative approaches. The incorporation of 3D-printing technology and the unconventional use of hernia mesh exemplify a viable strategy for achieving successful outcomes in challenging cases, emphasising the importance of adapting techniques to unique clinical scenarios. Level of evidence: Level 4

Resumen Antecedentes: Los tumores óseos requieren una adecuada evaluación clínico-radiográfica para su diagnóstico. Las radiografías simples son el método incruento usual para establecer el diagnóstico y evaluar diagnósticos diferenciales en el estudio de la patología tumoral ósea. Objetivo: Reconocer la frecuencia de las características radiográficas y asociarlas con patología tumoral ósea. Método: Se recolectaron datos radiográficos de 132 pacientes con patología tumoral confirmada mediante biopsia del servicio de tumores óseos del Hospital de Traumatología y Ortopedia Unidades Médicas de Alta Especialidad Dr. Victorio de la Fuente Narváez, Instituto Mexicano del Seguro Social, en Ciudad de México, durante el año 2019. Resultados: Integraron la muestra 132 pacientes. El tumor benigno más frecuente fue el osteocondroma (27.3%), y el maligno, el osteosarcoma (9.8%). Las lesiones líticas activas (odds ratio [OR]: 6.9; intervalo de confianza del 95% [IC95%]: 2.83-16.85) o agresivas (OR: 26.85; IC95%: 3.21-224) se asociaron a tumor de células gigantes. Las lesiones blásticas de estirpe ósea mal diferenciadas intraóseas (OR: 36.15; IC95%: 4.4-295.5) se asociaron a osteosarcoma. La reacción perióstica (OR: 36.15; IC95%: 4.4-295.5), el patrón apolillado o permeativo (OR: 11.75; IC95%: 1.26-109) y la ubicación central (OR: 3.03; IC95%: 1.37-6.69) se asociaron a lesiones tumorales malignas. Conclusiones: Las lesiones blásticas de estirpe ósea mal definidas intraóseas, la reacción perióstica y el patrón de destrucción apolillado o permeativo se asocian a lesiones malignas.

Abstract Background: Bone neoplasms require an adequate clinical-radiographic evaluation for their diagnosis. Plain radiographs are the usual method to establish the diagnosis and evaluate differential diagnoses in the study of bone tumor pathology. Objective: To recognize the frequency of radiographic characteristics and associate them with bone tumor pathology. Method: Radiographic data were collected from 132 patients with tumor pathology confirmed by biopsy from bone tumors service of the Traumatology and Orthopedics Hospital Unidades Médicas de Alta Especialidad Dr. Victorio de la Fuente Narváez, Instituto Mexicano del Seguro Social, Ciudad de México, during 2019. Results: 132 patients were registered. The most frequent benign tumor was osteochondroma (27.3%), and malignant was osteosarcoma (9.8%). Active lytic lesions (odds ratio [OR]: 6.9; 95% confidence interval [95% CI]: 2.83-16.85) or aggressive (OR: 26.85; 95% CI: 3.21-224) were associated with giant cells tumors. Poorly differentiated intraosseous blast lesions of bone lineage (OR: 36.15; 95% CI: 4.4-295.5) were associated with osteosarcoma. The periosteal reaction (OR: 36.15; 95% CI: 4.4-295.5), the moth-eaten or permeative pattern (OR: 11.75; 95% CI: 1.26-109) and the central location of the lesion (OR: 3.03; 95% CI: 1.37-6.69) were associated with malignant tumor lesions. Conclusions: Poorly defined intraosseous blast lesions of bone lineage, periosteal reaction, and moth-eaten or permeative pattern of destruction are associated with malignant lesions.

ABSTRACT Objective: Osteosarcoma lung metastases have a wide variety of CT presentations, representing a challenge for radiologists. Knowledge of atypical CT patterns of lung metastasis is important to differentiate it from benign lung disease and synchronous lung cancer, as well as to determine the extent of primary disease. The objective of this study was to analyze CT features of osteosarcoma lung metastasis before and during chemotherapy. Methods: Two radiologists independently reviewed chest CT images of 127 patients with histopathologically confirmed osteosarcoma treated between May 10, 2012 and November 13, 2020. The images were divided into two groups for analysis: images obtained before chemotherapy and images obtained during chemotherapy (initial CT examination). Results: Seventy-five patients were diagnosed with synchronous or metachronous lung metastases. The most common CT findings were nodules (in 95% of the patients), distributed bilaterally (in 86%), with no predominance regarding craniocaudal distribution (in 71%). Calcification was observed in 47%. Less common findings included intravascular lesions (in 16%), cavitation (in 7%), and the halo sign (in 5%). The primary tumor size was significantly greater (i.e., > 10 cm) in patients with lung metastasis. Conclusions: On CT scans, osteosarcoma lung metastases typically appear as bilateral solid nodules. However, they can have atypical presentations, with calcification being the most common. Knowledge of the typical and atypical CT features of osteosarcoma lung metastasis could play a key role in improving image interpretation in these cases.

RESUMO Objetivo: As metástases pulmonares do osteossarcoma têm uma grande variedade de apresentações tomográficas, o que é um desafio para os radiologistas. É importante conhecer os padrões tomográficos atípicos da metástase pulmonar para diferenciá-la de doença pulmonar benigna e câncer sincrônico de pulmão, bem como para determinar a extensão da doença primária. O objetivo deste estudo foi analisar as características tomográficas da metástase pulmonar do osteossarcoma antes da quimioterapia e durante a quimioterapia. Métodos: Dois radiologistas analisaram de modo independente as imagens de TC de tórax de 127 pacientes com osteossarcoma confirmado histopatologicamente, tratados entre 10 de maio de 2012 e 13 de novembro de 2020. As imagens foram divididas em dois grupos para a análise: imagens obtidas antes da quimioterapia e imagens obtidas durante a quimioterapia (TC inicial). Resultados: Setenta e cinco pacientes receberam diagnóstico de metástase pulmonar sincrônica ou metacrônica. Os achados tomográficos mais comuns foram nódulos (em 95% dos pacientes), distribuídos bilateralmente (em 86%), sem predominância de distribuição craniocaudal (em 71%). Observou-se calcificação em 47%. Alguns dos achados menos comuns foram lesões intravasculares (em 16%), escavação (em 7%) e o sinal do halo (em 5%). O tumor primário foi significativamente maior (> 10 cm) em pacientes com metástase pulmonar. Conclusões: Em imagens de TC, as metástases pulmonares do osteossarcoma tipicamente aparecem em forma de nódulos sólidos bilaterais. No entanto, podem ter apresentações atípicas, sendo a calcificação a mais comum. Conhecer as características tomográficas típicas e atípicas da metástase pulmonar do osteossarcoma pode ser fundamental para interpretar melhor as imagens nesses casos.

ABSTRACT Objectives: We examined the expression of Lnc-ZFAS1 in osteosarcoma and comprehensively evaluated its effects on osteosarcoma in vitro and vivo. Moreover, we revealed the regulatory mechanism between Lnc-ZFAS1 and miR-520b/miR-520e-mediated RHOC and provided a novel clue for ameliorating osteosarcoma. Method: The expression of Long non-coding RNA Zinc Finger Antisense 1 (LncRNA ZFAS1) osteosarcoma tissues and normal tissues in the TCGA database was analyzed. Then, LncRNA ZFAS1 expression was further verified in clinical samples and osteosarcoma cell lines (U2OS and KHOS), as well as the human osteoblast cell line hFOB1.19 by qRT-PCR. Thereafter, LncRNA ZFAS1 was overexpressed or silenced to explore its effects on cell proliferation, apoptosis, migration, invasion, and Epithelial-Mesenchymal Transition (EMT). The fundamental mechanism through which Lnc-ZFAS1 affects osteosarcoma progression was further investigated and verified. Results: We found that LncRNA ZFAS1 was upregulated in osteosarcoma, and Lnc-ZFAS1 overexpression facilitated osteosarcoma cells proliferation, migration, invasion and EMT, while Lnc-ZFAS1 silence exerted reverse influence. Mechanistically, Lnc-ZFAS1 functionally acted as a sponger of microRNA-520b (miR-520b) and micro-RNA-520e (miR-520e) to up-regulate Ras Homologue C (RHOC). In addition, depleted Lnc-ZFAS1 restrained osteosarcoma cells proliferation, migration, and invasion, which could be rescued by RHOC overexpression. Lnc-ZFAS1 was upregulated in osteosarcoma and Lnc-ZFAS1 could exert promoted impact upon osteosarcoma cells proliferation, migration, invasion, and EMT in vitro. Conclusions: Lnc-ZFAS1 acted sponger of miR-520b and miR-520e to promote RHOC, indicating that Lnc-ZFAS1/miR-520b/RHOC and Lnc-ZFAS1/miR-520e/RHOC axes might serve as potential therapeutic strategies against osteosarcoma.

ABSTRACT: Canine mammary neoplasms with malignant mesenchymal components, such as carcinosarcomas and sarcomas, belong to an uncommon and histologically heterogeneous group. Little is known about the biological behavior of these histogenic variants. This study aimed to compare the clinicopathological characteristics and the COX-2 immunohistochemical expression of different histologic subtypes of carcinosarcomas and sarcomas. Samples of 23 carcinosarcomas and 15 sarcomas from the mammary glands of female dogs were studied. Medical records were reviewed to obtain clinical data. Subsequently, histology microscope slides were analyzed to assess for mesenchymal subtypes, necrosis, vascular invasion, histologic grades, and lymph node metastasis. Immunohistochemistry was used to assess the COX-2 expression. The malignant mesenchymal proliferation was categorized into osteosarcomas (23/40), fibrosarcomas (5/40), liposarcomas (6/40) and chondrosarcomas (4/40). The osteosarcomatous differentiation was the most predominant type among the sarcomas and carcinosarcomas and was associated with vascular invasion (P=0.010) and lymph node metastases (P=0.014). High COX-2 expression was detected in 14.3% of the carcinosarcomas (carcinoma and/or sarcoma cells) and 27.3% of the sarcomas. The carcinosarcomas and sarcomas had similar clinical and pathological characteristics and developed as large tumors, with intratumoral necrosis and a predominance of high histologic grades, although the frequency of vascular invasion and lymph node metastasis was low. Osteosarcoma subtypes presented more aggressive characteristics than non-osteosarcoma subtypes.

RESUMO: Neoplasias mamárias caninas com componentes mesenquimais malignos, como carcinossarcomas e sarcomas, são um grupo de neoplasias pouco frequentes e histologicamente heterogêneas e pouco se sabe sobre o comportamento biológico das variantes histogênicas. O objetivo desse estudo é comparar as características anatomopatológicas e a expressão imunoistoquímica de COX-2 de diferentes subtipos histológicos de carcinossarcomas e sarcomas. Foram estudados 23 carcinosarcomas e 17 sarcomas da glândula mamária de cadelas. Os prontuários médicos foram revisados para obtenção de dados clínicos. Posteriormente, as lâminas histológicas foram avaliadas para acessar os subtipos mesenquimais, necrose, invasão vascular, grau histológico, metástase linfonodal. A imunoistoquímica foi realizada para avaliar a expressão de COX-2. Os tipos encontrados de proliferação mesenquimal maligna foram osteossarcoma (23/40), fibrossarcoma (7/40), lipossarcoma (6/40) e condrossarcoma (4/40). A diferenciação osteossarcomatosa foi predominante entre os sarcomas e carcinossarcomas e foi associado com invasão vascular (P=0,006) e metástase linfonodal (P=0,014). Uma expressão alta de COX-2 foi detectada em 14,3% dos carcinossarcomas (células carcinomatosas e/ou sarcomatosas) e 27,3% dos sarcomas. Os carcinossarcomas e sarcomas apresentaram características clínicas e patológicas semelhantes e se desenvolveram como tumores grandes, com necrose intratumoral e predomínio de alto grau histológico, mas com baixa frequência de invasão vascular e metástase distante. Os subtipos osteossarcomatosos apresentaram características mais agressivas quando comparados com subtipos não osteossarcomatosos.

ABSTRACT Objective Present the preliminary results of a case series using the surgical ankle arthrodesis technique with an intramedullary retrograde nail for bone tumors. Methods We present the preliminary data of 4 patients, 3 males and 1 female, with a mean age of 46,2 (range 32 to 58) years, with histology proven Giant Cell Tumour of bone in 3 and osteosarcoma in 1. The mean resection length of distal tibia was 11,75 (range 9 to 16) cm, and all the patients underwent reconstruction with a tibiotalocalcaneal arthrodesis with an intercalary allograft fixed by a retrograde intramedullary nail. Results Oncological follow-up evolved without evidence of local recurrence or disease progression in all patients. After a mean time of 69.5 (range 32 to 98 months), patients had a mean MSTS12 functional score of 82.5% (range 75 to 90). All tibial arthrodesis and diaphyseal osteotomy sites were fused within 6 months with a return to activities without complications related to coverage skin or infection. Conclusion No complications were recorded; all arthrodesis and diaphysial tibial osteotomy sites fused by 6 months, and the mean follow-up of those patients was 69,5 (range 32 to 988) months, with a mean functional MSTS score of 82,5% (range 75-90). Level of Evidence: IV; Retrospective Case Series.

RESUMO Objetivo Apresentar os resultados preliminares de uma série de casos utilizando a técnica cirúrgica de artrodese do tornozelo com haste intramedular retrógada para tumores ósseos. Métodos Apresentamos os dados preliminares de quatro pacientes, três homens e uma mulher, com idade média de 46,2 (variação de 32 a 58) anos, com histologia comprovada de tumor de células gigantes em três e osteossarcoma em um. O comprimento médio de ressecção da tíbia distal foi de 11,75 (variação de 9 a 16) cm, e todos os pacientes foram submetidos à reconstrução com uma artrodese tibiotalocalcaneana com um aloenxerto intercalar fixado por uma haste intramedular retrógrada. Resultados O acompanhamento oncológico evoluiu sem evidências de recidiva local ou progressão da doença, em todos os pacientes. Após um tempo médio de 69,5 (variação de 32 a 98 meses), os pacientes tiveram uma pontuação média funcional MSTS12 de 82,5% (variação de 75 a 90). Todos os locais de artrodese e osteotomia diafisária tibiais foram fundidos em 6 meses com retorno às atividades de vida diária sem complicações relacionadas à cobertura ou infecção. Conclusão Não foram registradas complicações; todos os locais de artrodese e osteotomia diafisária da tíbia fundiram-se em 6 meses, e o acompanhamento médio desses pacientes foi de 69,5 (variação de 32 a 988) meses, com uma pontuação média funcional MSTS de 82,5% (variação de 75-90). Nível de Evidência IV; Série de Casos Retrospectivos.

ABSTRACT Reconstructive surgery with endoprostheses is the chosen method for treating bone malignancies. Postoperative infections are frequent complications, and their treatment involves prolonged hospital stays and antibiotic therapy. Among the advancements aimed at reducing the rate of postoperative infection, the use of incisional negative pressure therapy (iNPT) has shown promising results, with no reports in the literature regarding its use in patients with such conditions. Objective: To evaluate the effectiveness of iNPT in reducing postoperative complications in surgeries for resection of bone tumors associated with modular endoprosthesis reconstruction. Methods: Retrospective case series of 16 patients diagnosed with osteosarcoma, who underwent resection and reconstruction with endoprosthesis associated with iNPT during the postoperative period. Follow-up was performed for a period of six months, and the evaluated outcomes were the incidence of postoperative infection and complications of the surgical wound. Results: The use of iNPT for a postoperative period of seven days resulted in only three (18.7%) cases of postoperative infection. No cases of wound dehiscence, seroma formation, or hematoma at the surgical site were observed. Conclusion: The rate of surgical wound complications in our case series is lower than that reported in most of the literature, and iNPT appears to be an efficient way to reduce the rate of local complications in reconstructive surgeries with endoprosthesis after resection of bone malignancies. Level of Evidence III, Retrospective Study.

RESUMO A cirurgia reconstrutiva com endopróteses é o método escolhido no tratamento de malignidades ósseas. As infecções pós-operatórias são complicações frequentes, e seu tratamento envolve internações e antibioticoterapia prolongadas. Entre os avanços que visam reduzir a taxa de infecção pós-operatória, o uso da terapia com pressão negativa incisional (TPNi) vem mostrando resultados promissores, não havendo relatos na literatura de seu emprego em pacientes com tal quadro. Objetivo: Avaliar a eficácia da TPNi em reduzir complicações pós-operatórias em cirurgias de ressecção de tumores ósseos associadas à reconstrução com endopróteses modulares. Métodos: Série de casos retrospectiva de 16 pacientes diagnosticados com osteossarcoma, submetidos à ressecção e reconstrução com endoprótese associada à TPNi durante o pós-operatório. Foi realizado seguimento por um período de seis meses e os desfechos avaliados foram incidência de infecção pós-operatória e complicações da ferida operatória. Resultados: O uso da TPNi por um período pós-operatório de sete dias resultou em apenas três (18,7%) casos de infecção pós-operatória. Não foram observados casos em que ocorreu deiscência da ferida operatória, formação de seromas ou hematomas no sítio cirúrgico. Conclusão: A taxa de complicações de ferida operatória em nossa série de casos é menor que a da maior parte da literatura, e a TPNi parece ser uma forma eficiente de reduzir a taxa de complicações locais em cirurgias reconstrutivas com endoprótese após ressecção de malignidades ósseas. Nível de Evidência III, Estudo Retrospectivo.

Abstract Chemotherapy is the main treatment option for advanced osteosarcoma, which is the most common type of primary bone malignancy. However, patients develop resistance rapidly and many succumb to the disease. Niclosamide, an anthelmintic drug, has been recently identified to display potent and selective anti-cancer activity. In this work, we show that niclosamide at sub-micromolar concentrations inhibits proliferation and migration, and induces apoptosis in both parental and chemo-resistant osteosarcoma cells, with much less toxicity in normal osteoblastic cells. Interestingly, chemo-resistant osteosarcoma cells are more sensitive to niclosamide compared to parental cells. We further identify that inhibition of β-catenin is the underlying mechanism of niclosamide’s action in osteosarcoma cells. In addition, we reveal that chemo-resistant osteosarcoma cells display increased β-catenin activity compared to parental cells, which might explain the hypersensitivity of chemo-resistant cells to niclosamide. Our work provides pre-clinical evidence that niclosamide can be repurposed for treating osteosarcoma. Our findings also suggest the therapeutic value of β-catenin to overcome osteosarcoma chemo-resistance. malignancy However disease Niclosamide drug anticancer anti cancer submicromolar sub micromolar migration chemoresistant chemo resistant Interestingly βcatenin β catenin niclosamides s addition preclinical pre clinical chemoresistance. chemoresistance resistance. chemo-resistance

Resumo O osteossarcoma é o tumor ósseo primário mais comum, com maior incidência na segunda década de vida, sendo as metástases pulmonares achado frequente. O padrão tomográfico mais comum das metástases pulmonares de osteossarcoma é o de múltiplos nódulos bem definidos no parênquima pulmonar, frequentemente com calcificações. Em razão da multiplicidade de apresentações das metástases pulmonares do osteossarcoma, inclusive com formas atípicas, o conhecimento dos aspectos dessas lesões na tomografia computadorizada do tórax é importante para a caracterização e avaliação da extensão da doença, além de permitir a diferenciação entre doença metastática e outras doenças pulmonares benignas ou malignas. Este ensaio discute os principais achados tomográficos das metástases pulmonares de osteossarcoma. vida frequente pulmonar calcificações atípicas malignas

Abstract Osteosarcoma is the most common primary bone tumor, with a higher incidence in the second decade of life, and it often leads to pulmonary metastases. The most common pattern seen on computed tomography is one of multiple well-defined nodules in the lung parenchyma, often with calcifications. Because of the variety of presentations of pulmonary metastases in osteosarcoma, including atypical forms, knowledge of the computed tomography aspects of these lesions is important for characterizing and evaluating the extent of the disease, as well as for distinguishing metastatic disease from other benign or malignant lung diseases. This essay discusses the main tomographic findings of pulmonary metastases from osteosarcoma. tumor life welldefined defined parenchyma calcifications osteosarcoma forms diseases

RESUMEN Introducción: Los tumores alrededor de la rodilla son frecuentes, a excepción de la rótula donde su localización es ocasional. En esta estructura anatómica existen características clínicas y epidemiológicas muy específicas según el tipo de tumor. Objetivo: Actualizar y brindar información sobre los tumores de la rótula. Métodos: La búsqueda y análisis de la información se realizó en un periodo de 62 días (primero de noviembre al 31 de diciembre de 2022) y se emplearon las siguientes palabras: patellar bone tumors, bone tumor AND patella, knee bone tumors a partir de la información obtenida se realizó una revisión bibliográfica de un total de 153 artículos publicados en las bases de datos: PubMed, Hinari, SciELO y Medline mediante el gestor de búsqueda y administrador de referencias EndNote, de ellos se utilizaron 30 citas seleccionadas para realizar la revisión, 28 de los últimos cinco años. Resultados: Se menciona la incidencia de los tumores benignos más frecuentes que afectan esta estructura anatómica, como el tumor de células gigantes. Se hace referencia a los tumores óseos malignos más reportados y su comportamiento clínico e imagenológico en especial el osteosarcoma. Se abordaron las metástasis de la rótula en particular las provenientes del pulmón. Conclusiones: Los tumores óseos de la rótula son lesiones infrecuentes, al comparar su incidencia con otros tumores de la rodilla. La presentación depende del tipo histológico y grado de afección ósea.

ABSTRACT Introduction: Tumors around the knee are frequent, except for the patella, where its location is occasional. In this anatomical structure there are very specific clinical and epidemiological characteristics depending on the type of condition. Objective: To update and provide information on patella tumors. Methods: The search and analysis of the information was carried out in a period of 62 days (November 1st to December 31st, 2022) and the following words were used: patellar bone tumors, bone tumor AND patella, knee bone tumors. From the information obtained a bibliographic review was carried out, a total of 153 articles published in the PubMed, Hinari, SciELO and Medline databases through the EndNote search manager and reference manager were found, of which 30 selected citations were used to carry out the review, 28 of the last five years. Results: The incidence of the most frequent benign tumors that affect this anatomical structure, such as the Giant Cell Tumor, is mentioned. Reference is made to the most reported malignant bone tumors and their clinical and imaging behavior, especially Osteosarcoma. Metastases of the patella were addressed, particularly those of the lung. Conclusions: Bone tumors of the patella are infrequent lesions, when comparing their incidence with tumors from the rest of the knee joint. Presentation depends on the histological type and degree of bone involvement.

Resumen: La transición epitelio-mesénquima (TEM) es la capacidad de las células epiteliales y mesenquimales de intercambiar de fenotipo de forma transitoria; su identificación en células tumorales carcinoma- tosas se ha asociado con fenotipos clínicos agresivos. En sarcomas, este evento biológico se encuentra en estudio. Objetivo: evaluar la expresión de dos factores de transcripción involucrados en la TEM mediante inmunohistoquímica en osteosarcoma en pacientes pediátricos y su asociación con desenlaces clínicos. Pacientes y Método: Estudio retrospectivo en menores de 18 años con diagnóstico de osteosarcoma. Se realizó inmunohistoquímica para Snail y Twist-1 en muestras obtenidas al momento del diagnóstico. Posteriormente fue explorada la correlación entre la positividad de los marcadores con los desenlaces clínicas y con la supervivencia global. Resultados: 53 pacientes fueron incluidos. Para Snail, se encontró positivo en localización citoplasmático en 26 casos (49,1%) y esto se correlacionó con la presencia de metástasis múltiples (p = 0,02) y metástasis de localización ósea distantes (p = 0,01). Twist fue positivo en localización nuclear en 45 casos (84,9%) y no se encontraron aso ciaciones con las variables clínicas analizadas. Conclusiones: Snail y Twist-1, se detectaron en una frecuencia importante en muestras de pacientes pediátricos con osteosarcoma. Snail citoplasmático se correlacionó con presencia de enfermedad metastásica múltiple y metástasis óseas distantes. La positividad de ambos marcadores sugiere la activación de estas proteínas como reguladores de eventos de TEM en este tumor y se plantea un rol en los fenómenos que se relacionan con la presentación clínica de la enfermedad.

Abstract: The epithelial-mesenchymal transition (EMT) is the ability of epithelial and mesenchymal cells to exchange phenotypes transiently. Its identification in carcinomatous cells has been associated with aggressive clinical phenotypes. In sarcomas, this ability is under study. Objective: to evaluate the expression of two transcription factors involved in EMT by immunohistochemistry in pediatric osteosarcoma and its association with clinical outcomes. Patients and Method: A retrospective cohort study in children under 18 years of age with osteosarcoma diagnosis. Immunohistochemistry was performed for Snail and Twist-1 expressions from samples collected at the time of diagnosis. Correlations between immunohistochemistry and the clinical outcomes and overall survival were performed. Results: 53 patients were included. There were 26 positive cytoplasmic cases (49.1%) in Snail expression and were correlated with the presence of multiple metastases (p = 0.02) and distant bone metastases (p = 0.01). On the other hand, 45 cases (84.9%) were positive in Twist-1 expression in the nuclear location, showing no association with the analyzed clinical variables. Conclusions: Snail and Twist-1 were frequently expressed in pediatric cases of osteosarcoma. Cytoplasmic Snail was correlated with the presence of multiple metastatic disease and distant bone metastases. The positivity of both markers suggests the activation of these proteins as regulators of EMT events in this tumor, suggesting a role in the phenomena related to the clinical presentation of the disease.

Abstract Objective To evaluate the survival time, the failure rate and its causes, and the functional results of cemented endoprostheses, with a polyethylene body, used after resection of primary bone tumors of the distal femur. Methods A retrospective study including 93 primary and 77 review procedures performed between 1987 and 2014. Survival was obtained by the Kaplan Meyer analysis, and the risk factors for implant failure were assessed through the Cox proportional risk model. The causes of endoprosthesis failure were classified according to Henderson et al. into five types: soft-tissue failure, aseptic loosening, structural fracture, infection, and tumor recurrence. The functional evaluation was performed using the functional classification system of the Musculoskeletal Tumor Society (MSTS) of bone sarcomas of the lower extremity, Brazilian version (MSTS-BR). Results Osteosarcoma was the most common diagnosis; 64.5% of the patients were younger than 20 years of age; the mean follow-up was of 124.3 months. The failure rate of the primary implant was of 54.8%, and the mean survival was of 123 months. The estimated survival of the primary implant was of 63.6%, 43.5%, 24.1%, and 14.5% in 5, 10, 15, and 20 years respectively. The most common cause of failure was type 2 (37.3%). Age ≤ 26 years and right side were risk factors for failure. The mean MSTS-BR score was of 20.7 (range: 14 to 27). Conclusion The results obtained for the failure rate and survival of the implant are in accordance with those of the literature, so the procedure herein studied is adequate and yields satisfactory functional results, even in the long term.

Resumo Objetivo Avaliar o tempo de sobrevida, a taxa de falha e suas causas, e os resultados funcionais de endopróteses cimentadas, com corpo em polietileno, empregadas após ressecção de tumores ósseos primários do fêmur distal. Métodos Estudo retrospectivo, que incluiu 93 procedimentos primários e 77 de revisão, realizados entre 1987 e 2014. A sobrevida foi obtida pela análise de Kaplan Meyer, e os fatores de risco para falha do implante foram avaliados por meio do modelo de riscos proporcionais de Cox. As causas de falha da endoprótese foram classificadas segundo Henderson et al. em cinco tipos: falha de partes moles, soltura asséptica, fratura estrutural, infecção e recorrência do tumor. A avaliação funcional foi realizada por meio do sistema de classificação funcional da Musculoskeletal Tumor Society (MSTS) para sarcomas ósseos da extremidade inferior, versão brasileira (MSTS-BR). Resultados Osteossarcoma foi o diagnóstico mais comum; 64,5% dos pacientes tinham menos de 20 anos; e o seguimento médio foi de 124,3 meses. A taxa de falha do implante primário foi de 54,8%, e a sobrevida média foi 123 meses. A estimativa de sobrevida do implante primário foi de 63,6%, 43,5%, 24,1%, 14,5% em 5, 10, 15 e 20 anos, respectivamente. A causa de falha mais comum foi a do tipo 2 (37,3%). Idade ≤ 26 anos e lado direito foram fatores de risco para falha. A pontuação média no MSTS-BR foi de 20,7 (variação: 14 a 27). Conclusão Os resultados obtidos para a taxa de falha e o tempo de sobrevida do implante estão de acordo com os da literatura, de forma que o procedimento estudado é adequado e apresenta resultados funcionais satisfatórios, inclusive em longo prazo.

Resumen El osteosarcoma extraesquelético es un tumor maligno de alto grado que representa menos del 2% de los sarcomas de partes blandas y que afecta principalmente a personas entre la quinta y sexta década de la vida. Típicamente el diagnóstico es tardío, con un período síntomas-diagnóstico extenso, >6 meses en comparación con el del osteosarcoma convencional. Comunicamos el caso de un hombre de 43 años que acudió con una tumoración en la región glútea y el muslo izquierdo de un año de evolución. Luego de estudios complementarios y una biopsia no concluyentes, se procedió a la resección quirúrgica del tumor con márgenes amplios. El estudio histológico de la pieza indicó osteosarcoma extraesquelético. El paciente tuvo una evolución muy buena, sin elementos de recidiva local ni compromiso a distancia luego de 20 meses de seguimiento.

Abstract Extraskeletal osteosarcoma (EOS) is a high-grade malignant tumor that accounts for less than 2% of soft tissue sarcomas and mainly engages people between the fifth and sixth decade of life. It is typically of late diagnosis, with an extensive symptom-diagnosis period greater than 6 months compared to conventional osteosarcoma. We report the case of a 43-year-old patient who presented in our service with a 1-year-old tumor localized in the gluteal and left thigh region. After inconclusive paraclinical studies and biopsy, the tumor was surgically resected with wide margins and diagnosed as EOS after the histological analysis of the piece. The patient showed a very good clinical and paraclinical progression without signs of local or distant recurrence after 20 months of follow-up.