骨膜骨肉瘤与高度恶性表面骨肉瘤

目的报告表面骨肉瘤的两种少见亚型,即骨膜骨肉瘤和高度恶性表面骨肉瘤的诊治经验。方法回顾 5例骨膜骨肉瘤和 4例高度恶性表面骨肉瘤患者的影像学和病理学特点,并对临床治疗结果进行分析。 5例骨膜骨肉瘤患者,男 1例,女 4例;年龄 28～ 42岁,平均 35岁;肿瘤位于胫骨上段者 4例,股骨下段者 1例。 4例高度恶性表面骨肉瘤患者,男 3例,女 1例;年龄 17～ 23岁,平均 19.25岁; 4例患者肿瘤均位于股骨下段。结果 5例骨膜骨肉瘤均予以广泛切除,除 1例因局部复发行截肢术,现无瘤生存 1年 3个月外,余 4例已无瘤生存 3～ 9年,平均 5年 9个月。 4例高度恶性表面骨肉瘤患者,虽经积极综合治疗,但仅 1例无瘤生存 7年; 1例术后 2年 5个月复发而截肢,现无瘤生存 1年 9个月; 1例于术后 2年 4个月死于肺转移;另 1例在确诊后 3个月死亡。结论骨膜骨肉瘤和高度恶性表面骨肉瘤各具鲜明的影像学和病理学特点,骨膜骨肉瘤恶性程度较低,应采用以局部广泛切除为主的手术治疗,预后相对较好;而高度恶性表面骨肉瘤的生物学行为则与经典的髓内骨肉瘤相似,预后较差,必须采用手术与化疗相结合的综合治疗方法。     

腓骨近端成骨肉瘤的外科治疗

目的 对腓骨近端成骨肉瘤患者的局部复发率和5年生存率进行评估.方法 1997年10月至2005年7月,12例腓骨近端成骨肉瘤患者中,男性9例,女性3例,平均年龄16岁(9～23岁).Enneking外科分期IIB期11例,III期1例.术前穿刺活检病理确诊后,除1例患者放弃治疗自动出院,其余11例均给予术前成骨肉瘤标准化大剂量化疗2个疗程后,手术切除肿瘤.按Malawer分型,I型切除8例,II型3例.术后继续进行术后化疗4个疗程,并定期复查.结果 仅有1例患者术后1年出现了局部复发,接受了再次手术切除,局部复发率为9%(1/11).确诊后自动出院的患者1年后死于双肺转移.III期1例患者半年后死于全身衰竭.2例IIB患者分别于术后1年和2年死于肺转移.12例患者获得随访,随访时间为6~117个月,平均60个月.11例患者Kaplan-Meier生存曲线5年生存率为72.7%.所有患者的膝关节功能稳定,腓总神经切除的患者术后带踝关节支架行走.结论 腓骨近端成骨肉瘤局部复发率较低,5年生存率和股骨远端和胫骨近端成骨肉瘤术后的基本相同.本研究证实对于腓骨近端肿瘤,边缘性切除并不影响腓骨近端成骨肉瘤的预后.术后外侧副韧带和股二头肌腱在胫骨近端外侧的止点重建对于膝关节的术后稳定性至关重要.     

新辅助化疗联合肿瘤型人工关节置换治疗膝关节周围骨肉瘤38例

[目的]探讨新辅助化疗联合肿瘤型人工关节置换应用于膝关节周围骨肉瘤保肢治疗的可行性。[方法]自2002年9月~2009年10月,病理活检确诊的38例膝关节周围骨肉瘤患者,采用Rosen T19方案化疗2个疗程后行人工关节置换术,术后化疗4~6个疗程。随访病例的关节功能恢复及肿瘤复发情况。[结果]37例患者获随访,随访时间18~62个月,平均49个月。术后关节活动功能恢复。ISOLS功能评定标准,术后优良率为83.8%,3例术后出现局部肿瘤复发,2例出现肺转移,2例局部感染。[结论]早期确诊,新辅助化疗联合人工关节置换术是膝关节周围骨肉瘤保肢治疗的有效措施。     

多中心成骨肉瘤的治疗

目的探讨多中心成骨肉瘤的治疗方法。方法1998年1月至2005年6月治疗多中心成骨肉瘤患者9例，男7例，女2例。9例患者的临床特征、影像学表现、病理学检查均证实多中心成骨肉瘤的诊断。其中6例患者初诊时即存在多发骨肉瘤病灶；3例初诊时为单一骨肉瘤病灶，而后分别在确诊6、8、11个月出现第二处骨肉瘤病灶。1例患者因经济原因放弃治疗，其余8例患者接受阿霉素60mg／m^2,顺铂100mg／m^2,氨甲蝶呤8-12g／m^2长春新碱1．4mg／m^2、异环磷酰胺12．5g／m^2化疗1周期。化疗后根据病灶数目、部位以及对化疗的反应等决定包括手术、化疗在内的进一步治疗方案。对病灶数目较少、病灶可广泛切除的患者，如果化疗反应好，则在化疗的基础上广泛切除肿瘤，手术原则同单发性骨肉瘤；如果全身病灶数目多、部分病灶位于中轴骨等不易广泛切除的部位，则根据病情采取适当的姑息手术。对上述化疗反应差的患者，应用三氧化二砷、紫杉醇、VP-16化疗。结果放弃治疗的1例患者于确诊5个月后死于肿瘤引起的全身衰竭，5例初诊存在多发骨肉瘤病灶的患者平均生存时间9．8个月，其中2例对化疗反应好且完成4周期以上化疗的患者平均生存时间为15个月，对化疗反应差以及未能完成化疗的3例患者平均生存时间仅为7．1个月。3例病灶不同时出现的多中心成骨肉瘤患者平均随访2年，2例带瘤生存，无肺转移；1例无瘤生存。结论多中心成骨肉瘤预后较差，经积极的化疗，能够延长患者生命，改善预后。     

表面骨肉瘤

目的探讨表面骨肉瘤的组织类型、临床、病理及影像学特征。方法回顾性分析经病理证实的表面骨肉瘤19例,其中骨膜骨肉瘤4例,部位分别为胫骨干中上段(3例)和腓骨下段(1例);X线片及CT显示肿物位于骨旁,外缘不规则,可见放射状骨针影;镜下为低度或中度恶性软骨肉瘤样改变。高度恶性表面骨肉瘤2例,肿物均位于股骨内侧;X线片显示肿物以广泛基底附于患骨,混杂骨膜反应;镜下显示高度恶性,似髓内型。去分化骨旁骨肉瘤1例,肿物位于股骨下端;患者曾先后4次手术,术后病理显示高分化组织内出现低分化区。经典骨旁骨肉瘤12例,肿物75%位于股骨下端干骺端后部。结果骨膜骨肉瘤4例均行保肢手术,已无瘤生存1.1～6.5年。高度恶性表面骨肉瘤2例,其中1例拒绝手术,3个月后死于肺及肝转移;另1例应用大剂量化疗及保肢治疗,现已无瘤生存19个月。去分化骨旁骨肉瘤1例,行假体旁复发性肿瘤切除,现已无瘤生存6个月。经典骨旁骨肉瘤的初始治疗均为保肢手术,其中9例随访1.2～9.6年,除1例局部复发、1例死于肺转移外,另外7例均无瘤生存。结论表面骨肉瘤四种组织类型各具有特殊性,应区别对待。骨膜骨肉瘤及经典骨旁骨肉瘤应以局部广泛切除或瘤段切除为主,预后较好;去分化型和高度恶性表面骨肉瘤恶性程度较高,预后较差。保肢或截肢均应配合有     

第一前肋恶性肿瘤切除重建的初步研究

[目的]探讨第一前肋恶性肿瘤手术切除及重建的外科治疗方法、临床疗效及并发症。[方法]回顾性分析本院2008年1月～2017年6月收治7例第一前肋恶性肿瘤患者的相关资料,男5例,女2例;左侧5例,右侧2例,年龄22～66岁,平均(35.24±10.62)岁。其肿瘤病理分别为软骨肉瘤3例、恶性纤维组织细胞瘤2例、骨肉瘤1例、纤维肉瘤1例。完善术前检查后均行CT引导下穿刺明确病理诊断。骨肉瘤患者行新辅助化疗后手术,其余患者病理明确后手术治疗。手术入路采用锁骨上入路,锁骨离断,显露第一肋骨并保护锁骨下动、静脉及臂丛神经,按术前预定截骨范围(肿瘤边缘外3 cm)咬骨钳离断肋骨后端,锁骨钢板固定,胸腔常规放置闭式引流。术后观察指标包括有无血气胸、臂丛神经损伤、肿瘤复发、锁骨愈合。[结果] 7例患者均安全完成手术,无术中危象及术中死亡者。术后随访9个月～4年。7例患者术后均有不同程度的血气胸,均经胸腔闭式引流后恢复;2例患者术后有臂丛神经损伤症状,上臂麻木和无力,经保守治疗后恢复;患者切口均I期愈合,无感染性血气胸等并发症。1例软骨肉瘤患者术后10个月软骨肉瘤局部复发再次行局部扩大切除,1例恶性纤维组织细胞瘤术后11个月多发转移后放弃治疗;其余患者随访期间未见肿瘤复发。患者锁骨骨折均愈合。[结论]锁骨离断后行第一前肋恶性肿瘤切除手术可以有效切除肿瘤组织,术中需注意保护臂丛神经,术后需注意治疗胸腔积液。     

四肢长骨恶性肿瘤并发骨折的手术时机及方法

[目的]探讨四肢长骨恶性肿瘤并发骨折的手术时机及手术方法。[方法]回顾1996年6月～2003年lO月收治的四肢长骨恶性肿瘤并发骨折17例，其中骨肉瘤4例，骨巨细胞瘤3例，尤文氏肉瘤1例，造釉细胞瘤1例，骨转移瘤8例。采用Ⅰ期外固定并化疗，Ⅱ期瘤段切除重建术4例；Ⅰ期行肿瘤病灶清除功能重建术11例；Ⅰ期截肢1例，Ⅱ期截肢1例。[结果]随访时间12～88个月，原发性恶性肿瘤9例中，肺转移死亡2例，其中1例局部复发；骨转移瘤8例中，死亡4例，其中1例局部复发。[结论]化疗敏感的原发恶性肿瘤并发骨折主张优先考虑Ⅰ期外固定并化疗，Ⅱ期瘤段切除重建；化疗不敏感的骨巨细胞瘤及骨转移瘤并发骨折应Ⅰ期行病灶清除功能重建。     

四肢软组织肉瘤26例临床分析

探讨四肢软组织肉瘤疗效与肿瘤分期,手术方法的关系。方法对２６例不同病期四肢软组织肉瘤患者行局部广泛切除和截肢术。结果１８例局部广泛切除术中Ⅰ期１４例,其中１１例术后存活５－１９年无复发转移,３例局部复发;Ⅲ期、Ⅳａ期４期术后均发徨局部复发转移。８例截肢术中３例术后１年６个月转移死亡,５例术后存活４－１８年无复发转移。     

三氧化二砷联合化疗治疗Ⅲ期成骨肉瘤、尤文肉瘤的初步报告

目的 探讨三氧化二砷（Arsenic trioxide,As2O3）联合化疗治疗转移性成骨肉瘤、尤文肉瘤的可行性。方法自2002年12月至2005年6月,32例转移性成骨肉瘤、尤文肉瘤患者接受了以三氧化二砷为主的二线化疗方案。其中男性19例,女性13例,年龄7～32岁。成骨肉瘤27例,尤文肉瘤5例;肿瘤转移部位包括肺转移25例,多发骨转移7例。所有病例均为手术后患者,术前及术后共接受过4～6周期的规范化疗。化疗方案：三氧化二砷、VP-16、紫杉醇。化疗2个周期28例,3个周期4例。结果所有患者均获得随访,随访时间6～36个月,平均20个月。经三氧化二砷联合化疗2个疗程后,5例完全缓解（15．6％）,转移病灶消失,无新发病灶出现;6例部分缓解（18．8％）;13例稳定（40．6％）,转移病灶无明显缩小,但出现明显钙化,其中完全钙化2例,部分钙化11例;8例进展（25％）,肿瘤体积增大或转移数目增多。21例治疗前碱性磷酸酶或乳酸脱氢酶增高的病例,9例（42．9％）明显下降。32例患者中病情持续稳定,肿瘤得到控制者24例,病情加重5例,死亡3例。结论三氧化二砷是一种低毒、有效的化疗药物,对于Ⅲ期成骨肉瘤、尤文肉瘤患者有较好的近期临床疗效。     

睾旁胚胎型横纹肌肉瘤5例报告并文献复习

目的:提高睾旁胚胎型横纹肌肉瘤的诊治水平。方法:回顾性分析5例睾旁胚胎型横纹肌肉瘤患者的临床资料,结合文献复习进行讨论。结果:5例患者中精索胚胎型横纹肌肉瘤2例、附睾胚胎型横纹肌肉瘤2例、鞘膜横纹肌肉瘤1例,临床病理分期Ⅰ期2例,Ⅱ期1例,Ⅳ期2例。5例患者最终均行根治性睾丸切除术及肿块完整切除术。1例Ⅰb期和1例Ⅱ期患者术后采用异环磷酰胺、长春新碱、足叶乙甙、丝裂霉素、顺铂化疗并配合局部放疗,余3例未行进一步治疗。2例Ⅰ期、1例Ⅱ期患者随访28、18、12个月未见复发和转移,1例Ⅳ期患者随访6个月后死于多发转移,1例Ⅳ期随访6个月未见复发和转移,后失访。结论:早期诊断,根治性手术并辅助化疗、放疗是治疗睾旁胚胎型横纹肌肉瘤的有效手段。     

CD-147在骨肉瘤中的表达及其与临床病理指标的相关性实验研究

[目的]验证CD-147在骨肉瘤组织中的表达及与临床病理指标的相关性.[方法]SABC法免疫组化分析55例骨肉瘤组织中CD-147基因的表达,并对其与骨肉瘤临床病理的关系进行统计学分析.[结果]作者的研究提示CD-147基因在骨肉瘤组织有高表达,并且与其外科分级具有明显相关性.[结论]骨肉瘤CD-147蛋白的表达与肿瘤恶性程度密切相关,对骨肉瘤诊断和预后评估具有重要价值.     

Osteosarcoma of the spine: experience in 26 patients treated at the Massachusetts General Hospital

Background contextBecause of the low incidence, treatment recommendations for spinal osteosarcoma are guided by the results of small series and case reports. Many include patients who presented for treatment over the course of three to four decades.PurposeThe goal of this investigation was to report the treatments, results, and overall survivorship of 26 patients treated for osteosarcoma of the spine at a single institution.Study designRetrospective prognostic series (Level III evidence).Patient sampleTwenty-six patients treated at a single center for osteosarcoma of the spine over a 26-year period.Outcome measuresEstimation of patient survival, local recurrence, and the presence of metastatic disease.MethodsWe performed a retrospective review of cases of osteosarcoma involving the spine treated at our institution between 1982 and 2008. Medical charts, radiology reports, pathology reports, and operative notes were reviewed for all patients. Available imaging studies were also reviewed. The log-rank test was used to compare baseline differences between groups. Survivorship analysis was performed using Kaplan–Meier methodology. The effect of Paget osteosarcoma, type of resection, presence of local recurrence, tumor size, surgical margins, and metastases on overall survival were also investigated using the log-rank test.ResultsTwenty-six patients were included for review in this study. Twenty individuals were treated surgically, and 24 were treated with radiation with a mean dose of 62.2 Gy (range 20–84.7 Gy). Twenty-five patients received chemotherapy. Of those treated surgically, seven received en bloc resection. The median overall survival for all patients in our series was 29.5 months (standard error 14.7, 95% confidence interval 0.6–58). Local recurrence developed in 7 patients (27%), and metastasis occurred in 16 individuals (62%). Patients with Paget osteosarcoma had worse overall survival (p<.001).ConclusionsResults presented here confirm a poor prognosis for patients with spinal osteosarcoma. Although combination therapies, including surgery, chemotherapy, and high-dose radiation, achieve adequate short-term survival, the 5-year mortality rate remains high.     

老年骨肉瘤10例治疗总结

目的探讨老年骨肉瘤（≥60岁）的临床特点和治疗效果。 方法回顾性分析2007年1月至2017年3月期间山东大学齐鲁医院骨科收治的≥60岁的骨肉瘤患者10例,女性8例,男性2例,年龄60~76岁,平均（66±6）岁,病变位于股骨5例、踝关节软组织1例、多中心1例、骨盆（Ⅲ区）1例、肱骨1例、距骨1例。确诊后行截肢术2例,截肢术结合化疗2例,广泛切除术1例,广泛切除术结合化疗3例,边缘切除结合放疗1例,单纯化疗1例。 结果10例患者中,4例就诊时病史已超过6个月,2例就诊时已出现肺转移,5例合并基础疾病,2例血清ALP水平升高（>125 U/L）。影像学方面,7例为混合型,1例为溶骨型,1例为成骨型,1例位于软组织。肿瘤组织类型方面,普通型骨肉瘤7例,骨旁骨肉瘤2例,髓内高分化性骨肉瘤1例。10例患者随访3.5~124个月,平均（40±37）个月。1例接受单纯化疗的肺转移患者于明确诊断后3.5个月死亡,另1例肺转移患者接受转移灶射频消融术,随访58个月带瘤生存,1例距骨骨肉瘤复发后行截肢术。其余7例均未出现肿瘤复发或远处转移。 结论老年骨肉瘤临床较为少见,具有不同于青少年骨肉瘤的临床特点和预后,应早期明确诊断,采取适合患者自身情况的治疗方法,以尽可能降低复发和转移的发生率,延长生存期。     

The threat of misdiagnosis of primary osteosarcoma over the age of 60: a series of seven cases and review of the literature

Background

Osteosarcoma is the most common, non-haematopoietic, primary malignant bone tumour with an incidence of 0.3–0.5 per 100,000. There is some discrepancy in literature concerning the peaks of incidence of osteosarcoma. Some describe only one peak which arises in adolescence, whilst others report a bimodal age distribution with a second peak over the age of 60. In this retrospective study, we evaluated osteosarcoma patients over age 60 treated at our department and reviewed previous studies from the literature.

Patients and methods

Sixty-four patients (40 male, 24 female) with a mean age of 29 years (from 7 to 82) were treated for primary osteosarcomas. At the time of diagnosis, seven patients (two male and five female) were over 60 years of age with a mean follow-up of 46 months after definite diagnosis.

Results

Three out of seven osteosarcomas were primarily radiologically or histologically misdiagnosed, but only one was mistreated with intramedullary nailing at a trauma centre. At last follow-up, two patients had died from the disease, three were alive with disease, and two had no evidence of osteosarcoma.

Conclusions

We did not find an increased incidence of primary osteosarcoma in the elderly; yet, older patients had a higher rate of misdiagnosis due to untypical radiological findings in combination with longer times from the onset of first symptoms to definite diagnosis. In cases of pathological fracture, it is essential to assess whether it is caused by mechanical stress or a primary or secondary tumour before leading into mistreatment, especially in older patients.     

影响骨肉瘤生存率的多因素回归分析

[目的]探讨影响骨肉瘤术后生存的预后因素.[方法]对40例骨肉瘤患者平均随访56个月,计算5年总生存率及无瘤生存率,选择临床因素及分子生物学指标,采用比例风险模型进行多因素回归分析.[结果]本组5年总生存率为53.78%、无瘤生存率为45.00%;Cox多因素回归分析显示:肿瘤体积、肿瘤细胞坏死率(TCNR)、P-gp的表达是影响骨肉瘤术后预后的独立因素.[结论]肿瘤体积、P-gp的表达与骨肉瘤的预后呈负相关,TCNR与预后呈正相关.肿瘤体积、TCNR、P-gp的表达可作为判断预后的独立指标.     

Primary hyperparathyroidism and osteosarcoma: examination of a large cohort identifies three cases of fibroblastic osteosarcoma.

To study a possible relationship between hyperparathyroidism and osteosarcoma, we reviewed 1234 osteosarcoma patients. In this cohort, only three patients had a diagnosis of both hyperparathyroidism and fibroblastic osteosarcoma. These results indicate that hyperparathyroidism is not more prevalent in patients with osteosarcoma than in the general population. However, the presence of hyperparathyroidism may modify the histologic and cytologic features of osteosarcoma. INTRODUCTION: The finding of osteosarcoma in rats receiving human PTH(1-34) raised the question of whether hyperparathyroidism might be a risk factor for development of osteosarcoma in humans. MATERIALS AND METHODS: To study a possible relationship between hyperparathyroidism and osteosarcoma, we reviewed the medical records of 1234 osteosarcoma patients seen at The M.D. Anderson Cancer Center since 1948. Our study focused on clinical, biochemical, radiologic, and histopathologic findings indicative of primary hyperparathyroidism and the features of osteosarcoma. RESULTS: Of the 1234 cases reviewed, 3 patients had a diagnosis of both primary hyperparathyroidism and osteosarcoma. In two cases, hyperparathyroidism preceded the osteosarcoma, and in one case, both conditions were diagnosed at the same time. In two cases with concomitant hyperparathyroidism and osteosarcoma, features of osteitis fibrocystica were identified. The third patient was treated for hyperparathyroidism 3 years before osteosarcoma was diagnosed. All three patients had histologic features of fibroblastic osteosarcoma, a type that accounts for no more than 20% of osteosarcomas. To assess whether the prevalence of hyperparathyroidism was greater than expected in the normal population, we compared the age- and sex-specific prevalence in our cohort to a population of healthy individuals in Tromso, Norway. This analysis showed no significant differences between the two populations, despite the fact that a higher prevalence of hyperparathyroidism (6.9% versus 1.6%) was noted in the 60- to 69-year-old female osteosarcoma age group. CONCLUSIONS: Our results indicate that hyperparathyroidism is not more prevalent in affected individuals with osteosarcoma than in the general population. The finding of fibroblastic osteosarcoma in all three patients raises the question of whether coexistent hyperparathyroidism may modify the cytologic and histologic features of the malignancy.     

Extra-osseous osteosarcoma: a clinical and histopathological study of four cases.

Four cases of extra-osseous osteosarcoma were found among 242 cases recorded as osteosarcoma in the Swedish Cancer Registry during the years 1958 to 1968. The tumours occurred in middle-aged and elderly patients. Three of the tumours were situated in the proximal part of the thigh and one in the scapular region. Histopathologically, all tumours were subclassified as osteoblastic osteosarcomas. The patients were treated by primary local excision which in one case was followed by a radical en bloc excision of the entire tumour bed. All cases subjected to simple excision died of metastatic disease five to twenty-four months after diagnosis. The patient treated by en bloc excision is alive and apparently free from disease fourteen years after diagnosis.     

Oncological and functional outcome of periosteal osteosarcoma

Background:

Periosteal osteosarcoma is an uncommon variant of osteosarcoma which constitutes less than 2% of all osteosarcomas. Whereas adequate surgical excision remains the cornerstone of treatment, the role of chemotherapy in this tumor is still unclear. Existing literature contains very few single center studies on the outcomes for periosteal osteosarcomas and any additional information will help in better understanding of these uncommon lesions. This study aims to evaluate the oncologic and functional outcomes of treatment of periosteal osteosarcoma treated at our institute.

Materials and Methods:

A retrospective analysis of 18 cases of periosteal osteosarcoma treated between January 2001 and December 2010 was carried out. There were 12 males and 6 females. The mean age at presentation was 16.3 years (range 5-26 years). Tibia and femur were the most common sites (n = 8). 16 of 18 patients received chemotherapy, 16 had limb sparing resection, one had an amputation and one had rotationplasty. Of the 16 patients with limb salvage, conventional wide excision was done in 11 cases. In 5 cases tumor was excised with hemicortical excision. Of the 11 cases treated with wide excisions, 4 patients underwent an osteoarticular resection and in 7 patients a joint preserving segmental intercalary resection was done.

Results:

All patients were available for followup. Surgical margins were free in all patients. A good response to chemotherapy was seen in 4/11 cases and poor in 6/11 cases. In one case the histological response was not discernible due to predominant chondromyxoid nature of the tumor. The median followup was 61 months (range: 18-130 months). There were two local recurrences (11%) at 9 and 18 months postsurgery. Pulmonary metastasis subsequently occurred in 4 cases (22%). Fourteen patients are currently alive and continuously disease free. Disease free survival at 5 years was 77.8% and overall survival (OVS) was 83.3%. Patients without marrow involvement had a better OVS at 5 years when compared with patients with marrow involvement (90% vs. 75%) (P = 0.23).

Conclusion:

Surgical excision remains the mainstay of treatment. Intramedullary involvement may suggest aggressive disease biology. The role of chemotherapy is still debatable and multicenter studies are needed to provide guidelines.     

Well-differentiated osteosarcoma of the jaw bones: a clinicopathologic study of 15 cases

Well-differentiated osteosarcoma of the jaw bones is rare, and is often confused with a variety of benign fibroosseous lesions. To better understand its clinicopathologic features, we reviewed our experience with 15 cases. The patients included 7 males and 8 females (age range 14 to 66?y; mean 42.8?y). Six of the tumors arose in the mandible, and 9 in the maxilla. Microscopically, the tumors were infiltrative, relatively hypocellular, and consisted of monomorphic, minimally atypical spindle cells that were usually arranged in fascicles. The tumor cells were intimately related to the surfaces of elongated trabeculae of neoplastic woven bone that lacked osteoblastic rimming. Nine patients were treated with wide excision, 2 patients with marginal excision, and 2 patients with excision and radiation therapy. After definitive therapy, there were no reports of recurrence or metastasis over an average follow-up of 34 months (range 1 to 80 mo). Well-differentiated gnathic osteosarcoma is a low-grade malignancy that may be successfully treated with wide local excision. The prognosis in our series was excellent.