DNA methylation profile discriminates sporadic giant cell granulomas of the jaws and cherubism from their giant cell-rich histological mimics.

Sporadic giant cell granulomas (GCGs) of the jaws and cherubism-associated giant cell lesions share histopathological features and microscopic diagnosis alone can be challenging. Additionally, GCG can morphologically closely resemble other giant cell-rich lesions, including non-ossifying fibroma (NOF), aneurysmal bone cyst (ABC), giant cell tumour of bone (GCTB), and chondroblastoma. The epigenetic basis of these giant cell-rich tumours is unclear and DNA methylation profiling has been shown to be clinically useful for the diagnosis of other tumour types. Therefore, we aimed to assess the DNA methylation profile of central and peripheral sporadic GCG and cherubism to test whether DNA methylation patterns can help to distinguish them. Additionally, we compared the DNA methylation profile of these lesions with those of other giant cell-rich mimics to investigate if the microscopic similarities extend to the epigenetic level. DNA methylation analysis was performed for central (n = 10) and peripheral (n = 10) GCG, cherubism (n = 6), NOF (n = 10), ABC (n = 16), GCTB (n = 9), and chondroblastoma (n = 10) using the Infinium Human Methylation EPIC Chip. Central and peripheral sporadic GCG and cherubism share a related DNA methylation pattern, with those of peripheral GCG and cherubism appearing slightly distinct, while central GCG shows overlap with both of the former. NOF, ABC, GCTB, and chondroblastoma, on the other hand, have distinct methylation patterns. The global and enhancer-associated CpG DNA methylation values showed a similar distribution pattern among central and peripheral GCG and cherubism, with cherubism showing the lowest and peripheral GCG having the highest median values. By contrast, promoter regions showed a different methylation distribution pattern, with cherubism showing the highest median values. In conclusion, DNA methylation profiling is currently not capable of clearly distinguishing sporadic and cherubism-associated giant cell lesions. Conversely, it could discriminate sporadic GCG of the jaws from their giant cell-rich mimics (NOF, ABC, GCTB, and chondroblastoma).

Metaphyseal chondroblastoma in a pediatric patient.

Chondroblastoma is a rare, benign neoplasm usually located in the epiphyses and apophyses of the long bones in the immature skeleton. Radiologically, these tumors have a classic appearance of a lytic lesion with chondroid matrix surrounded by a thin sclerotic rim. Here, we describe the case of a 5-year-old male who presented with a chondroblastoma unusually located exclusively in the metaphyseal region, which led to an elusive diagnosis. The presence of tumors outlying the traditional location or epidemiological spectrum, along with the potential for histopathological misdiagnosis, can pose a diagnostic and therapeutic challenge for the treating team.

The diagnosis and treatment of tibial intercondylar chondroblastoma

OBJECTIVES: To investigate the diagnosis and treatment of tibial intercondylar chondroblastoma. METHODS: We retrospectively analyzed the diagnosis and treatment of 12 patients with tibial intercondylar chondroblastoma admitted to the orthopedics department from May 2011 to February 2016; among them were 4 males and 3 females aged 10-19 years, with an average age of 15.7 years. Tibial intercondylar chondroblastoma was on the left and right side in 7 and 5 cases, respectively. The preoperative average Lysholm score of the knee joint was 68 (42-87). A posteromedial approach was applied in all cases. The incisions were approximately 5-8 cm in length. Complete curettage and inactivation were performed after fenestration, and allogeneic bone grafts were transplanted. Then, the posterior cruciate ligament insertion was fixed with 5.0 suture anchors. All patients were followed up with regularly to monitor for tumor recurrence, observe bone graft healing, and reassess the Lysholm score of the knee. RESULTS: Patients were followed for 7-55 months, and the median follow-up time was 19 months. One patient experienced tumor relapse 4 months after the operation. Incision, inactivation and cementation were performed. Then, the bone was fixed with anchors. In the other 11 patients, the bone graft healed over an average period of 6.2 months (4-10 months), with good functional recovery postoperatively. The average postoperative Lysholm score of the knee was 91 (81-95). CONCLUSION: Tibial intercondylar chondroblastoma has unique clinical and imaging characteristics and can effectively be treated by curettage followed by the inactivation, transplantation and fixation of allogeneic bone grafts with suture anchors through a posteromedial approach.

Chondroid Tenosynovial Giant Cell Tumor of the Temporomandibular Joint: A Rare Case Report

Abstract Tenosynovial giant cell tumor of diffuse type (TGCT-d) or pigmented villonodular synovitis (PVNS) is a locally aggressive lesion that mostly affects the joints of long bones. Chondroid tenosynovial giant cell tumor (CTGCT) or PVNS with chondroid metaplasia is a rare distinct subset of synovial tumors that has a predilection for the TMJ. We report a rare case of CTGCT in the TMJ, initially misdiagnosed as temporomandibular disorder (TMD). A 51-year-old woman was referred to the surgeon with the chief complaint of TMJ pain for 5 years and a past history of an unsuccessful TMD treatment. Extraoral examination revealed discrete preauricular swelling and restricted mandibular range of motion. Panoramic radiograph and computerized tomography showed destruction of the mandibular fossa and condyle. Histologically, the tumor was composed by large mononuclear cells with prominent eosinophilic cytoplasm and grooved nuclei, small histiocytoid cells, osteoclast-like multinucleated cells, brown pigmentation and areas of chondroid metaplasia. Morphological and immunohistochemical characteristics lead to the final diagnosis of CTGCT. The rarity of CTGCT could be attributed to the lack of recognition of this lesion, with cases diagnosed as chondroblastomas, synovial chodromatosis and chondrosarcoma. The patient received immediate reconstruction and recurrence was found 22 months after initial intervention. TGCT-d and CTGCT of the TMJ can present similar symptoms to TMD, but clinicians must distinguish both lesions by complete examination, imaging and, when necessary, histopathologic evaluation.

Resumo Tumor de células gigantes tenossinovial do tipo difuso (TCGT-d) ou sinovite vilonodular pigmentada (SVP) é uma lesão localmente agressiva que afeta principalmente as articulações dos ossos longos. Tumor de células gigantes tenossinovial condroide (TCGTC) ou SVP com metaplasia condroide é um tipo distinto e raro de tumor sinovial que tem a predileção pela articulação temporomandibular (ATM). Nós relatamos um caso raro de TCGTC da ATM, inicialmente diagnosticado, equivocadamente, como disfunção temporomandibular (DTM). Uma mulher de 51 anos foi encaminhada ao cirurgião com a queixa principal de dor na ATM por 5 anos, e uma história de tratamento de DTM sem sucesso. O exame extrabucal revelou discreto aumento de volume preauricular e movimentação mandibular restrita. A radiografia panorâmica e a tomografia computadorizada evidenciaram destruição da fossa mandibular e côndilo. Histologicamente, o tumor era composto por células mononucleares grandes, com amplo citoplasma eosinofílico e núcleo sulcado, pequenas células histiocitoides, células multinucleadas semelhantes a osteoclastos, pigmentação acastanhada e áreas de metaplasia condroide. As características morfológicas e imuno-histoquímicas levaram ao diagnóstico final de TCGTC. A raridade desta lesão pode estar associada ao seu não reconhecimento, sendo casos diagnosticados como condroblastoma, condromatose sinovial ou condrossarcoma. A paciente recebeu reconstrução imediata e recorrência foi observada 22 meses após a intervenção inicial. TCGT-d e TCGTC da ATM podem apresentar sintomas similares à DTM, mas os clínicos devem diferenciar ambas as lesões por meio do exame clínico completo, exames de imagem e, quando necessário, avaliação histopatológica.

Reconstruction with non-vascularized fibular autograft after resection of clavicular benign tumor.

Chondroblastoma is a rare, benign cartilaginous neoplasm that accounts for approximately 1% of all bone tumors, and approximately 4% of all chondroblastomas arise in the clavicle. Here, we report a case of chondroblastoma in the right clavicle. 27-year-old female patient presented with a 12-month history of shoulder pain. Based on radiological and pathological examination, the diagnosis was compatible with chondroblastoma. After resection of the tumor, 1 cm of the distal clavicle was preserved, 15 cm of the non-vascularized fibula was taken from the contralateral leg and placed on the site of the clavicle and fixed with hook plate at distal clavicle and reconstruction plate attached to the sternum. 13 months of follow-up is scheduled for removal of osteosynthesis material, finding full consolidation of sternoclavicular segment and the distal segment. A good functional outcome was apparent after a limited 14-month follow-up, and the patient was highly satisfied with the result. We found no recurrence or metastasis.

Condroblastoma de la cabeza femoral y reconstrucción con aloinjerto osteocondral: Reporte de caso / Femoral head chondroblastoma and reconstruction with osteochondral allograft: Case report

El condroblastoma de la cabeza femoral es un tumor poco frecuente (aproximadamente 1 o 2% de los tumores benignos de hueso), se presenta con mayor frecuencia en pacientes jóvenes de sexo masculino. El condroblastoma es más frecuente en el húmero proximal, fémur proximal, fémur distal y tibia proximal. La cabeza femoral es el tercer sitio más frecuente, No existe un tratamiento específico para esta entidad; se han descrito desde osteotomías acetabulares, injertos osteocondrales, injertos vascularizados de peroné, etcétera, todos reportando buenos resultados. Pero es clínicamente impredecible si no recibe tratamiento. Se presenta un caso que se manejó con aloinjerto osteocondral y la evolución de tres años posterior al procedimiento quirúrgico...

Femoral head chondroblastoma is an infrequent tumor, accounting for approximately 1-2% of benign bone tumors. It occurs more frequently in young male patients. It's most frequent locations include the proximal humerus, proximal femur, distal femur and proximal tibia. The femoral head is the third most frequent site of this tumor. There is no specific treatment for this entity; reported treatments range from acetabular osteotomies and osteochondral grafts, to vascularized fibular grafts, all of them with good results. However, this tumor is clinically unpredictable if left untreated. We report a case managed with osteochondral graft and followed-up for three years after the surgical procedure...

Condroblastoma de presentación atípica en concomitancia a osteomielitis crónica operado con cirugía radical: caso clínico / Chondroblastoma of atypical presentation in conjunction with chronic osteomyelitis operated through radical surgery: clinical case

INTRODUCCIÓN: El condroblastoma es un tumor óseo benigno representando menos del 1 por ciento del total de tumores óseos; se presenta principalmente en jóvenes. De etiología controversial, se desarrolla habitualmente en centros secundarios de osificación en huesos largos. No hay casos que describan su existencia junto a osteomielitis ni su tratamiento quirúrgico. CASO CLÍNICO: Mujer de 15 años con antecedente de osteomielitis de inicio reciente, diagnosticada con cintigrafía y biopsia en escápula izquierda; a pesar de tratamiento médico antibiótico con cloxacilina persiste dolor, eritema, impotencia funcional y aumento de volumen progresivo. Cintigrafía de control confirma nula respuesta a tratamiento inicial. Tomografía computada (TC) informa probable proceso tumoral osteolítico cortical con reacción de partes blandas en casi la totalidad de la escápula incluyendo cavidad glenoidea. Biopsia quirúrgica informa condroblastoma sospecha de variante agresiva resolviéndose con escapulectomía total con resección de cabeza humeral y posterior pexia clavículo-humeral. Biopsia definitiva de pieza quirúrgica informa osteomielitis crónica y condroblastoma agresivo. Evolución favorable en controles posteriores sin signos de recidiva local ni a distancia. DISCUSIÓN: La nula respuesta clínica al tratamiento inicial y su progresión hizo sospechar un proceso tumoral no diagnosticado inicialmente debido a que la biopsia no incluyó focos del condroblastoma. El manejo clásico del condroblastoma consiste en curetaje y relleno con autoinjerto; pero debido a la localización atípica, posibilidad de malignización y coexistencia con proceso osteomielítico crónico se optó por cirugía innovadora que consistió en resección total y posterior pexiaclavículo-humeral

INTRODUCTION: A Chondroblastoma is a benign bone tumor, corresponding to less than 1 percent of all bone tumors, and affecting mainly young people. Commonly developing in secondary centers of ossification in large bones, there are no cases describing its existence along with osteomyelitis, nor its surgical treatment. CLINICAL CASE: Woman (15 Y/O) with a history of osteomyelitis onset caused by a recent fall is diagnosed through scintigraphy and biopsy in the left scapule. Despite treatment with cloxacillin, pain persisted, erythema developed, with a progressive increase of volume and functional impotence. Control scintigraphy confirms no response to initial treatment. Computed Tomography (CT) informs of a probable cortical osteolysis tumoral process with soft tissue reactions in almost the entire scapule including glenoid cavity. Surgical biopsy shows chondroblastoma and, suspecting an agressive variant, it is resolved to perform a total scapulectomy with resection of scapule head and subsequent humerus-claviclepexia. Definitive biopsy of surgical piece shows chronic osteomyelitis and agressive chondroblastoma. The evolution of the patient is normal on follow-up controls, not presenting any signs of local neither distant relapse. DISCUSSION: The non-existence of a response to the initial treatment and its progression made us suspect of a natural process that was not diagnosed initially because the biopsy didn't include chondroblastoma focus. The usual chondroblastoma treatment consists of curetting and autograft filling; but due to the atypical location, and the possibility of coexistence with malignant and chronic osteomyelitic process we chose to apply an innovative surgery that consisted of total resection and subsequent pexia.

Tratamiento y reconstrucción en tumores óseos del húmero con prótesis no convencional tipo RIMAG / Treatment and reconstruction of bone tumors of the with a rimag unconventional prosthesis

Introducción: La cirugía conservadora y de reconstrucción con prótesis no convencional en tumores del húmero sin compromiso neurovascular está indicada ayudando a conservar las funciones del hombro, del codo y la mano. El húmero es el tercer sitio más frecuentemente afectado por los tumores benignos, agresivos, malignos y metastásicos provocando limitación funcional o pérdida de la extremidad. Material: Pacientes con tumor óseo en el húmero sin invasión neurovascular, que cumplan con los criterios de selección. Prótesis no convencional tipo RIMAG, no cementada, con ajuste diafisario y bloqueo con pernos. Métodos: Entre Junio de 1995 y Diciembre de 2011, fueron tratados 39 pacientes con tumores intraarticulares tipo I según las clasificaciones de Malawer y Enneking, con resección tumoral y reconstrucción con prótesis no convencional y partes blandas. Resultados: Se estudiaron 18 mujeres y 21 hombres entre 12-72 años, con tumores como: tumores de células gigantes (14), osteosarcomas (7), metástasis (7), condrosarcomas (6), sarcomas de Ewing (2), condroblastoma (2), y quiste óseo aneurismático (1). Doce pacientes murieron por enfermedad sistémica, el resto de la serie sobreviven. Los márgenes quirúrgicos fueron amplios con resección humeral entre los 100 a 230 mm. Los resultados funcionales fueron evaluados de acuerdo a la Sociedad de Tumores Musculoesqueléticos; 13 excelentes, 16 buenos, 5 fallas, 5 pobres. Discusión: El nivel de la resección no restringe la colocación de esta prótesis que permite realizar revisiones a futuro. El resultado satisfactorio depende del tamaño de la resección y musculatura del hombro conservada y no es limitado por el tamaño de la resección mejorando la discapacidad del paciente.

Introduction: Conservative surgery and reconstruction with an unconventional prosthesis are indicated for tumors of the humerus without neurovascular compromise, as they help preserve shoulder, elbow and hand function. The humerus is the third most frequent site of benign, aggressive, malignant and metastatic tumors that cause functional limitation or limb loss. Material: Patients with a bone tumor of the humerus without neurovascular involvement that met the inclusion criteria. Unconventional, uncemented RIMAG prosthesis with diaphyseal fit and locking bolts. Methods: 39 patients with intraarticular type I tumors according to the Malawer and Enneking classification were treated with tumor resection and reconstruction with an unconventional prosthesis and soft tissues. Results: Patients enrolled included 18 females and 21 males ages 12-72 years with tumors such as: giant cell tumors (14), osteosarcomas (7), metastasis (7), chondrosarcomas (6), Ewing's sarcomas (2), chondroblastoma (2) and aneurysmatic bone cyst (1). Twelve patients died due to systemic disease and the remaining patients survived. Surgical margins were broad, with humeral resection between 100 and 230 mm. Functional results were assessed according to the Muscoloskeletal Tumor Society score as 13 excellent, 16 good, 5 failures and 5 poor. Discussion: The resection level does not restrict the placement of this prosthesis, which permits future revisions. An appropriate result depends on the resection size and the preserved shoulder musculature and it is not limited by the size of resection, thus improving patients' disability.

Resultado do acompanhamento clínico-radiológico pós-cirúrgico do condroblastoma / Results from clinical and radiological follow-up, after surgical treatment of chondroblastoma

OBJETIVO: Avaliar o resultado clínico e radiológico, a longo prazo, de pacientes submetidos ao tratamento cirúrgico do condroblastoma, entre 2003 e 2009, pela mesma equipe cirúrgica e empregando a mesma técnica operatória. MÉTODOS: Foi realizado estudo retrospectivo de 12 pacientes com diagnóstico histológico de condroblastoma, atendidos entre 2003 e 2009, na Fundação Pio XII (Hospital de Câncer de Barretos - Barretos, SP) e submetidos ao tratamento cirúrgico com ressecção intralesional, adjuvância com eletrocauterização e substituição por metilmetacrilato (11 casos) ou enxerto ósseo autólogo de crista ilíaca (um caso). A avaliação pré-operatória incluía exame físico, radiografias simples do local, ressonância nuclear magnética ou tomografia axial computadorizada local, além de cintilografia óssea. Os pacientes foram avaliados clínica e radiologicamente, segundo protocolo predefinido, com radiografias seriadas e avaliação funcional, conforme o escore funcional de Enneking. RESULTADOS: A idade média do diagnóstico foi de 14A e 4M, sendo o local preferencial de acometimento a epífise distal do fêmur (75 por cento), seguido pela tíbia proximal (16,6 por cento) e calcâneo (8,4 por cento). Houve prevalência maior no sexo masculino em relação ao sexo feminino (3:1). Em três casos houve necessidade prévia de biópsia. Durante o seguimento, não evidenciamos recidiva local do tumor e todos os pacientes apresentaram excelente resultado funcional, com escore de Enneking entre 20 e 30, com a técnica cirúrgica empregada. CONCLUSÃO: O tratamento cirúrgico do condroblastoma, com ressecção intralesional, uso de adjuvância, com eletrocauterização e substituição por metilmetacrilato ou enxerto ósseo produz bons resultados.

OBJECTIVES: To evaluate the long-term clinical and radiological results from patients who underwent surgical treatment of chondroblastoma, between 2003 and 2009, by the same surgical team, using the same operative technique. METHODS: A retrospective study was conducted on 12 patients with histological diagnoses of chondroblastoma, who were attended between 2003 and 2009 at the Pius XII Foundation (Barretos Cancer Hospital, Barretos, State of São Paulo). These patients underwent surgical treatment with intralesional resection of the tumor, adjuvant electrocauterization and replacement with methyl methacrylate (11 cases) or an autologous graft from the iliac crest (one case). The preoperative evaluation included physical examination, plain radiographs of the site, magnetic resonance imaging, computed axial tomography and bone scintigraphy. The patients were assessed clinically and radiologically according to a predefined protocol, with a series of plain radiographs, and a functional assessment in accordance with the Enneking functional score. RESULTS: The average age at the time of diagnosis was 14 years and 4 months. The most frequent location affected was the distal femoral epiphysis (75 percent), followed by the proximal tibial epiphysis (16.6 percent) and the calcaneus (8.4 percent). There was higher prevalence among the female patients than among the male patients (3:1). In three cases, preoperative biopsy was necessary. During the follow-up, there was no evidence of local tumor recurrence, and all the patients presented an excellent functional result from the surgical technique used, with Enneking scores ranging from 20 to 30. CONCLUSION: Surgical treatment of chondroblastoma, using intralesional resection, adjuvant electrocauterization and replacement with methyl methacrylate or bone graft produced good results.

RESULTS FROM CLINICAL AND RADIOLOGICAL FOLLOW-UP, AFTER SURGICAL TREATMENT OF CHONDROBLASTOMA.

OBJECTIVES: To evaluate the long-term clinical and radiological results from patients who underwent surgical treatment of chondroblastoma, between 2003 and 2009, by the same surgical team, using the same operative technique. METHODS: A retrospective study was conducted on 12 patients with histological diagnoses of chondroblastoma, who were attended between 2003 and 2009 at the Pius XII Foundation (Barretos Cancer Hospital, Barretos, State of São Paulo). These patients underwent surgical treatment with intralesional resection of the tumor, adjuvant electrocauterization and replacement with methyl methacrylate (11 cases) or an autologous graft from the iliac crest (one case). The preoperative evaluation included physical examination, plain radiographs of the site, magnetic resonance imaging, computed axial tomography and bone scintigraphy. The patients were assessed clinically and radiologically according to a predefined protocol, with a series of plain radiographs, and a functional assessment in accordance with the Enneking functional score. RESULTS: The average age at the time of diagnosis was 14 years and 4 months. The most frequent location affected was the distal femoral epiphysis (75%), followed by the proximal tibial epiphysis (16.6%) and the calcaneus (8.4%). There was higher prevalence among the female patients than among the male patients (3:1). In three cases, preoperative biopsy was necessary. During the follow-up, there was no evidence of local tumor recurrence, and all the patients presented an excellent functional result from the surgical technique used, with Enneking scores ranging from 20 to 30. CONCLUSION: Surgical treatment of chondroblastoma, using intralesional resection, adjuvant electrocauterization and replacement with methyl methacrylate or bone graft produced good results.

Benign bone tumors subperiosteal on the talar neck resected anthroscopically: case reports / Tumores ósseos benignos subperiosteais do colo do tálus ressecados artroscopicamente: relatos de caso

Two cases of benign chondral tumors of the talar neck region (an osteoid osteoma and a chondroblastoma) were described. Because of their specific, unusual site they could be resected by arthroscopy. The imaging aspects, incidence in foot bones and possibilities of treatment were discussed, and a literature review is presented.

Dois casos de tumores condrais benignos na região do colo do tálus (um osteoma osteoide e um condroblastoma) foram descritos. Puderam ser resectados por artroscopia devido à localização específica e pouco comum. Discutiram-se os aspectos sobre exames de imagens, a incidência em ossos do pé e as possibilidades de tratamento, além de apresentar uma revisão da literatura.

Condroblastoma pélvico / Pelvic Chondroblastoma

Este artículo describe el caso de una mujer de 24 años de edad con un condroblastoma de localización pélvica, con una masa a la altura de la cresta iliaca derecha, de seis meses de evolución y crecimiento progresivo. Los rayos X mostraron una lesión osteolítica con densidad heterogénea y extensión hacia los tejidos blandos; el estudio histopatológico evidenció un condroblastoma. Los condroblastomas son tumores óseos benignos productores de cartílago que aparecen en las epífisis de los huesos largos de personas jóvenes. Alrededor del 75% de estos tumores afectan los huesos largos, principalmente el fémur, la tibia y el húmero; excepcionalmente se localizan en los huesos planos craneofaciales y en los huesos pélvicos. Los condroblastomas tienen características radiológicas e histopatológicas distintivas, y pese a su comportamiento biológico benigno, pueden causar una alta morbilidad para los pacientes, debido a su localización y a su tratamiento exclusivamente quirúrgico.

This article describes the case of a 24-year old woman with a pelvic chondroblastoma localized at the top of the right iliac crest, with six months of evolution and progressive growth. X-rays revealed an osteolytic lesion with heterogeneous density, extending toward soft tissue; the hisopathologic study provided evidence of chondroblastoma. Chondroblastomas are benign bone tumors producers of cartilage which appears in the long bone epiphysis of young people. Nearly 75% of such tumors affect the long bones, principally the femur, the tibia, and the humerus; exceptions include those in the flat craniofacial bones and the pelvis bones. Chondroblastomas have distinct radiological and histopathologic characteristics, and despite their benign biological behavior, can cause elevated morbidity among patients due to their localization and being treated exclusively with surgery.

Condroblastoma do osso esfenóide / Chondroblastoma of the sphenoid bone

Introdução: Condroblastoma é uma rara neoplasia benigna cartilaginosa, altamente destrutiva, que caracteristicamente surge na epífise de ossos longos em pacientes jovens. Sua ocorrência é extremamente rara na base do crânio, normalmente ocorrendo no osso temporal. Objetivo: Descrever um raro caso de um paciente apresentando um condroblastoma de osso esfenóide que invadia a fossa média, submetido a ressecção cirúrgica com sucesso, sem recorrência após 2 anos. Relato do Caso: W.J.S., 37 anos, masculino, encaminhado ao ambulatório de otorrinolaringologia com otalgia persistente e de forte intensidade há 3 meses. Apresentava otoscopia normal e sem tumorações visíveis. Tomografia computadorizada evidenciou massa tumoral em fossa infra-temporal à esquerda, invadindo fossa cerebral média. Biópsia sugeria tumor de células gigantes. Realizada ressecção ampla por abordagem anterior via osteotomia orbito-zigomática. Durante a cirurgia, confirmando achados tomográficos, não foi encontrado envolvimento do osso temporal. Exame histopatológico evidenciou condroblastoma. Após 18 meses da cirurgia, não apresenta queixas, sem déficits motores, sensitivos ou de nervos cranianos e sem sinais tomográficos de recorrência. Conclusão: Destaca-se a importância do diagnóstico diferencial do condroblastoma nas lesões da base do crânio e sua abordagem terapêutica, cujo objetivo sempre deve ser a maior ressecção possível com a máxima preservação de função.

Introduction: Chondroblastoma is an uncommon cartilaginous benign neoplasm, highly destructive, which specifically appears in the epiphysis of long bones in young patients. Its occurrence is extremely rare in the cranial base, normally occurring in the temporal bone. Objective: To describe a rare case in a patient presenting with a sphenoid bone chondroblastoma that invaded the middle cranial cavity, submitted to a successful surgical resection, without recurrence after 2 years. Case Report: W.J.S, 37 years old, male, forwarded to the otorhinolaryngology service with persistent and strong otalgia for 3 months. He had normal otoscopy and without visible tumorations. The computerized tomography confirmed tumor mass in the left infra-temporal cavity, invading the middle cranial cavity. The biopsy suggested giant cells tumor. After wide resection by frontal approach via orbitozygomatic osteotomy. During the surgery, we confirmed tomographic statements and didn't find temporal bone involvement. The histopathological exam confirmed chondroblastoma. After 18 months after the surgery, he doesn't present with complaints, without motor, sensitive deficits or of cranial nerves and without recurrence tomographic signals. Conclusion: The importance of differential diagnosis of chondroblastoma is remarkable in the cranial base lesions and its therapeutic approach, whose objective must always be the major possible resection with the maximum function conservation.