Fibrosarcoma Of Bone Research Articles

Primary fibrosarcoma of the distal femur. Report of a rare case

Fibrosarcoma of bone is a relatively rare malignant neoplasia, representing less than 5% of all bone tumors. It is distinguished from other bone sarcomas by the presence of spindle-shaped tumor cells located among intertwining bundles of collagen fibers, without any other type of histological differentiation, such as the formation of cartilage or bone.
 In the present report, we present a rare case of primary fibrosarcoma in the distal femur in a 45-year-old patient with complaints of mild pain and swelling in the right knee joint for approximately 6 months. After imaging evaluation, a biopsy was performed; in the second stage, a subsequent resection of 16 cm of the distal femur and its replacement with a tumor endoprosthesis was performed. Three months postoperatively, no local recurrence or metastasis of the tumor was observed.

Comparison of clinical features between patients with bone and soft tissue fibrosarcomas.

Fibrosarcomas predominantly arise in soft tissues, but can also develop in bone. Because of their rarity, whether bone development has an impact on clinical features has not been addressed. We included fibrosarcoma patients diagnosed between 1983 and 2016 in the Surveillance, Epidemiology, and End Results database. Differences in clinical features between fibrosarcoma of bone (FS-B) and fibrosarcoma of soft tissue (FS-ST) were investigated. After excluding patients without information regarding cause of death, site of origin, distant tumor or survival, 1443 patients were included. Of those, 98 patients had FS-B. Patients with FS-B were younger, more frequently male, with fibrosarcomas that more often developed in an extremity and were histologically high-grade. In contrast, no difference in potential to metastasize was observed. Survival was almost equal between FS-B and FS-ST (FS-B/FS-ST: cancer-specific survival, hazard ratio [HR]: 1.2, 95% confidence interval [CI]: 0.8-1.7; overall survival, HR: 1.3, 95% CI: 0.9-1.7). Our results clearly indicated that patient backgrounds differed, such as younger age and greater tendencies to affect males, develop in an extremity and show high-grade tumor in patients with FS-B. In contrast, no differences were observed in distant metastatic potential or survival.

The Management of Head and Neck Sarcoma.

To describe the incidence, types, features, treatment and outcomes of head and neck sarcoma managed at a treatment center in eastern China. Cases of head and neck soft tissue sarcoma and osteogenic sarcoma treated at the Stomatology Hospital of Nanjing University between 2008 and 2018 were retrospectively analyzed. Patient characteristics, site of lesion, main presenting symptoms, treatment, histology, local recurrence, development of metastatic disease, duration of follow-up and survival rates are described and compared. Sixty-three patients were diagnosed with head or neck sarcoma of which 42.9% had soft tissue sarcoma and 57.1% had osteogenic sarcoma. Of soft tissue sarcoma patients, the most frequently observed histologies were fibrosarcoma and malignant fibrous histiocytoma. Of 36 cases of osteogenic sarcoma, osteosarcoma, and fibrosarcoma of bone were most frequent. Mean latency period between initial symptoms and clinical presentation was 4.5 months. Radical resection was performed on 56 patients. For 33 patients, resection and radiotherapy were used and 10 patients received a triple combination of resection, chemotherapy and radiotherapy. Within the observation period, 17 patients died. Head and neck sarcomas, although rare, can represent a variety of pathological diagnoses. Surgery remains the main intervention although the data suggest chemotherapy, radical resection and irradiation as treatment. Outcomes are poor with high rates of local recurrence. Positive prognostic factors were tumor-free resection margins and choice of therapy. Due to the rarity of head and neck sarcoma, information remains limited and choice of treatment should be within the focus of clinical multi-center studies.

Abstract 3421: Comparison of mutations in different subtypes of sarcomas and its clinical implications

Abstract Background: Sarcoma is a malignant cancer that arises from transformed cells of mesenchymal origin. Sarcoma has the characteristics of low incidence and wide distribution of onset age. Sarcoma patients have poor prognosis and very limited selection of approved targeted drugs. Till now, the genomic features of sarcoma patients in China have not been well understood. Here we present the comprehensive genomic features of 202 sarcoma patients and compared mutations in different subtypes of sarcomas. Methods: Deep sequencing targeting 450 cancer genes was performed on FFPE and matched blood samples collected from 202 sarcoma patients. Based on the histology patients included 33 osteosarcoma (OS), 24 rhabdomyosarcoma (RMS), 20 liposarcoma (LPS), 19 fibrosarcoma (FBS), 16 leiomyosarcoma (LMS), 14 Ewing’s sarcoma (ES), 11 hemangiosarcoma (HMS), 10 synovial sarcoma (SS), 9 chondrosarcoma (CDS), and 46 others in this study. Genomic alterations (GAs) including single nucleotide variants (SNVs), insertions and deletions, copy number variations (CNV) and fusions were assessed. Results: Based on the deep sequencing results, there are 1219 somatic mutations detected in all 202 sarcomas, average 6.0 mutations per sample. The most common GAs of LPS, ES and SS’s are consistent with those mentioned in NCCN guidelines (MDM2 55%, EWSR1 78.6% and SS18 80%, respectively). OS, RMS and LMS shared the same most common GAs of TP53 (25%-50%). The second ranked common GAs were NCOR1 (24%), FRS2 (20.8%), ATRX (25%) genes, and the third ranked GAs were RB1 (24%), CDK4 (16.7%) and MAP2K4 (25%) genes. 161/202 patients (79.7%) harbored at least one actionable mutations which might benefit from FDA approved drugs or drugs were under investigation in clinical trials. All FBS, 93.8% LMS and 90.9% HMS have actionable mutations, however, only 10% SS and 35.7% ES have actionable mutations. 8 samples have CNV (including MDM2/4, EGFR and CCND1) which was related to hyper-progression of immunotherapy. All these 8 samples were bone tumor including 4 OS, 1 CDS, 2 ES and 1 fibrosarcoma of bone. Conclusions: Through the comprehensive genomic profiling, different types of sarcomas showed different characteristics of genomic alterations, and potential therapeutic targets may be identified for the patients. Further, NGS provides information on whether or not patients may have the potential hyper-progression of immunotherapy. Citation Format: Xinghua Song, Zuping Lian, YanBin Xiao, Kunpeng Bu, Ye Qiu, Tao Ji, Dan Liu, Angen Liu, Kai Wang. Comparison of mutations in different subtypes of sarcomas and its clinical implications [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3421.

Fibrosarcoma of Mandible Presenting As Secondary Primary Tumour - A Cytological Diagnosis

Fibrosarcoma of bone occur in any location but mainly affects long bone. Its occurrence in craniofacial region is about 15%, mandible being the most common site. Fibrosarcoma of hed and neck area represents 5% of all malignant intraosseous tumours. It is commonly seen between 3rdto 6thdecades of life. Here we present a case in 65 years old female with past history of radiotherapy for carcinoma of buccal mucosa and now presents with fibrosarcoma of the left jaw which was diagnosed by FNAC and confirmed by biopsy.

P0165 The management of head and neck sarcomas: 10-Year experience from a clinical institute in east China

Background We aimed to describe the incidence, type, treatment, outcomes and features of head and neck sarcomas in a major institute of east China. Methods Cases of head and neck soft tissue sarcoma (STS) and osteogenic sarcomas treated at Stomatology Hospital of Nanjing University from 2003 to 2013 were retrospectively analysed. Information regarding patient characteristics, site of the lesion, main presenting symptoms, treatment, histology, local recurrence, development of metastatic disease, duration of follow-up, and survival was obtained. Findings 63 patients were diagnosed with head and neck sarcomas (aged 3–83 years, mean 43.1 years). 27 (42.9%) cases were soft tissue sarcoma and 36 (57.1%) were osteogenic sarcoma. In the patients with soft-tissue sarcoma, common histologies were fibrosarcoma (9), malignant fibrous histiocytoma (6), rhabdomyosarcoma (3), leiomysarcoma (3), neurofibrosarcoma (2), angiosarcoma (1), synovial sarcoma (1), Kaposi’s sarcoma (1), and olfactory neuroblastoma (1). Of the 36 cases of osteogenic sarcoma, 26 had osteosarcoma, three cases were fibrosarcoma of bone, four were malignant fibrous histiocytoma of bone, and two were Ewing’s sarcoma. There was only one case of chondrosarcoma. Initial symptoms were local swelling (48, 76.2%) and pain (29, 46.0%). The latency period between first symptoms and clinical presentation was 4.5 months. The most common treatment was surgery. A radical resection was done in 56 patients. In 33 patients, resection and radiotherapy was used. Ten patients received resection, chemotherapy, and radiotherapy. Of these patients, 17 died within the observation period. Interpretation Surgery remains the mainstay treatment for head and neck sarcomas. According to our data, treatment should possibly include chemotherapy, radical resection, and irradiation.

Incidental benign metastasizing leiomyoma in a patient with bone sarcoma: a case report.

Background. The benign metastasizing leiomyoma is an exceptionally rare entity; it presents with ectopic leiomyoma nodules with a benign pattern. Symptoms vary according to the anatomic location. The diagnosis is histopathological, usually in patients with history of hysterectomy. Case Presentation. A 36-year-old female with 2-month history of left knee pain was diagnosed with bone fibrosarcoma. A CT scan showed pulmonary nodules. The patient started neoadjuvant chemotherapy. Conservative surgery of pelvic limb was achieved. A new CT scan reported pulmonary nodules that remained in relation to the previous CT. A nodule resection by thoracotomy and TOB (transoperative biopsy) was performed. The final pathology report described benign proliferative lesions consistent with benign metastatic leiomyoma. Conclusions. Benign metastatic leiomyoma is a rare condition presenting with uterine and extrauterine nodules most commonly in the lung. The diagnosis is histopathological. The surgical procedure must be reserved for selected patients.

Malignant fibrous histiocytoma and fibrosarcoma of bone: a re-assessment in the light of currently employed morphological, immunohistochemical and molecular approaches

Malignant fibrous histiocytoma (MFH) and fibrosarcoma (FS) of bone are rare malignant tumours and contentious entities. Sixty seven cases labelled as bone MFH (57) and bone FS (10) were retrieved from five bone tumour referral centres and reviewed to determine whether recent advances allowed for reclassification and identification of histological subgroups with distinct clinical behaviour. A panel of immunostains was applied: smooth muscle actin, desmin, h-caldesmon, cytokeratin AE1-AE3, CD31, CD34, CD68, CD163, CD45, S100 and epithelial membrane antigen. Additional fluorescence in situ hybridisation and immunohistochemistry were performed whenever appropriate. All cases were reviewed by six bone and soft tissue pathologists and a consensus was reached. Follow-up for 43 patients (median 42 months, range 6-223 months) was available. Initial histological diagnosis was reformulated in 18 cases (26.8 %). Seven cases were reclassified as leiomyosarcoma, six as osteosarcoma, three as myxofibrosarcoma and one each as embryonal rhabdomyosarcoma and interdigitating dendritic cell sarcoma. One case showed a peculiar biphasic phenotype with epithelioid nests and myofibroblastic spindle cells. Among the remaining 48 cases, which met the WHO criteria for bone FS and bone MFH, we identified five subgroups. Seven cases were reclassified as undifferentiated pleomorphic sarcoma (UPS) and 11 as UPS with incomplete myogenic differentiation due to positivity for at least one myogenic marker. Six were reclassified as spindle cell sarcoma not otherwise specified. Among the remaining 24 cases, we identified a further two recurrent morphologic patterns: eight cases demonstrated a myoepithelioma-like phenotype and 16 cases a myofibroblastic phenotype. One of the myoepithelioma-like cases harboured a EWSR1-NFATC2 fusion. It appears that bone MFH and bone FS represent at best exclusion diagnoses.

Primär maligne Knochentumoren

Among human neoplasms, primary malignant bone tumors are fairly rare. They present an incidence rate of roughly 10 cases per 1 million inhabitants per year. During childhood (<15 years), the percentage of malignant bone tumors amounts to 6% of all infantile malignancies. Only leukemia and lymphoma show a higher incidence in adolescence. Of all primary malignant bone tumors, 60% affect patients younger than 45 years and the peak incidence of all bone tumors occurs between 15 and 19 years. The most common primary malignant bone tumors are osteosarcoma (35%), chondrosarcoma (25%), and Ewing's sarcoma (16%). Less frequently (≤ 5%) occurring tumors are chordoma, malignant fibrous histiocytoma of bone, and fibrosarcoma of bone. Vascular primary malignant tumors of bone and adamantinoma are very rare. Staging of the lesion is essential for systemic therapeutic decision-making and includes complete imaging and histo-pathological confirmation of the suspected entity. In most cases, this is established by open- or image-guided biopsy. Based on this information, an interdisciplinary tumor board will determine the individual therapeutic approach. Endoprosthetic or biological reconstruction following wide tumor resection is the most common surgical therapy for primary malignant bone tumors. There is vital importance in a thorough postoperative follow-up and continous after-care by a competent tumor center which is permanentely in charge of therapy.

Array comparative genomic hybridization reveals frequent alterations of G1/S checkpoint genes in undifferentiated pleomorphic sarcoma of bone

Undifferentiated pleomorphic sarcoma of bone (UPSb) is a rare tumor often difficult to differentiate from fibrosarcoma of bone (FSb), diagnostically. We applied array comparative genomic hybridization (array CGH) to screen for genes with potential importance in the tumor and compared the results with alterations seen in FSb. Twenty-two fresh frozen tissue specimens from 20 patients (18 primary tumors and 4 local recurrences) with UPSb were studied. DNA was isolated and hybridized onto Agilent 244K CGH oligoarrays. The hybridization data were analyzed using Agilent DNA Analytics Software. The number of changes ranged from 2 to 168 (average = 66). Losses were most frequently seen at 8p, 9p, 10, 13q, and 18q, and gains at 4q, 5p, 6p, 7p, 8q, 12p, 14q, 17q, 19p, 20q, 22q, and X. Homozygous deletions of CDKN2A, RB1, TP53, and ING1 were seen in 8/20, 7/20, 3/20, and 2/20 cases, respectively. Hypermethylation of both p16(INK4a) and p14(ARF) was found in two cases with loss at CDKN2A. Inactivation either of CDKN2A, RB1, or TP53 was detected in 18/20 cases. One case showed high level gains of CDK4 and MDM2. Frequent gains were seen at MYC, PDGFRA, KIT, and KDR. Immunohistochemical positivity of KIT, PDGFRA, KDR, and PDGFRB was found in 8/14, 5/14, 4/14, and 4/14 cases, respectively. The regions most significantly discriminating between UPSb and FSb included RB1 and MYC. No homozygous deletions of RB1 were found in FSb. In conclusion, our analysis showed the disruption of G1/S checkpoint regulation to be crucial for the oncogenesis of UPSb.

Frequent deletion of CDKN2A and recurrent coamplification of KIT, PDGFRA, and KDR in fibrosarcoma of bone—An array comparative genomic hybridization study

Very little is known about the genetics of fibrosarcoma (FS) of bone. We applied array comparative genomic hybridization (CGH) to identify genes and genomic regions with potential role in the pathogenesis of this tumor. Seventeen patients with FS of bone were included in the study. Array CGH analysis was carried out in 13 fresh frozen tissue specimens from 11 of these patients (nine primary tumors and four local recurrences). DNA was extracted and hybridizations were performed on Agilent 244K CGH oligoarrays. The data were analyzed using Agilent DNA Analytics Software. The number of changes per patient ranged from 0 to 132 (average = 43). Losses were most commonly detected at 6q, 8p, 9p, 10, 13q, and 20p. CDKN2A was homozygously deleted in 7/11 patients. Hypermethylation of both p16(INK4a) and p14(ARF) was found in 1/14 patients. An internal deletion of STARD13 was found in a region with common losses at 13q13.1. The most frequent gains were seen at 1q, 4q, 5p, 8q, 12p, 15q, 16q, 17q, 20q, 22q, and Xp. Single recurrent high level amplification was detected at 4q12, including KIT, PDGFRA, and KDR. No activating mutations were found in any of them. Immunohistochemistry revealed expression of PDGFRA and/or PDGFRB in 12/17 samples. Moreover, small regions of gains pinpointed genes of particular interest, such as IGF1R at 15q26.3 and CHD1L at 1q21.1. In conclusion, our analysis provided novel findings that can be exploited when searching for markers for diagnosis and prognosis, and targets of therapy in this tumor type.

Tiling resolution array comparative genomic hybridization analysis of a fibrosarcoma of bone

Fibrosarcoma of bone is a rare malignant tumor accounting for less than 5% of all primary malignant bone neoplasms. There is very limited knowledge regarding the molecular genetics of this tumor, and there are no cytogenetic data available. In the present study, a fibrosarcoma deriving from the left iliac bone of a 10-year-old girl was characterized using cytogenetics, fluorescence in situ hybridization (FISH), and whole genome tiling resolution array comparative genomic hybridization (CGH). Cytogenetic and FISH analyses revealed a ring chromosome 6 as the sole acquired aberration, a finding corroborated by array CGH. The ring formation, however, did not result in any gain of genetic material. Nor did the breakpoints in 6p25 and 6q14 seem to affect any known gene loci in such a way that the ring formation could have resulted in the creation of a fusion gene or in the exchange of regulatory sequences. Thus, a reasonable interpretation of the pathogenetic significance of the ring formation would be that it resulted in the loss of one or more putative tumor suppressor gene loci distal to the two breakpoints.

Malignant fibrous histiocytoma of bone: Analysis of genomic imbalances by comparative genomic hybridisation and C-MYC expression by immunohistochemistry

Malignant fibrous histiocytoma (MFH) of bone is a rare, highly malignant tumour. As very little is known about its genetic alterations, 26 bone MFHs were analysed by comparative genomic hybridisation (CGH). Twenty-three tumours (89%) had DNA sequence copy number changes (mean, 7.2 changes per sample). Gains were more frequent than losses (gains:losses = 2.5:1). Minimal common regions for the most frequent gains were 8q21.3-qter (35%), 9q32-qter (35%), 7q22-q31 (35%), 1q21-q23 (31%), 7p12-pter (31%), 7cen-q11.2 (31%) and 15q21 (31%). Minimal common regions for the most frequent losses were 13q21-q22 (42%) and 18q12-q22 (27%). High-level amplifications were detected in 8 out of the 26 tumours (31%). The only recurrent amplifications, 1q21-q23 and 8q21.2-q22, were present in two samples (8%). As copy number increase at 8q24 (the locus of C- MYC) was frequent, the expression of C- MYC was studied by immunohistochemistry. Increased levels of c-myc protein were detected in 7 out of 21 tumours studied (33%). 81% of the samples studied both by CGH and immunohistochemistry showed concordant results. Furthermore, the findings of the present study were compared to previous publications on osteosarcoma, soft tissue MFH and fibrosarcoma of bone. Clear differences were detected in CGH aberration patterns, further supporting the concept of bone MFH as an individual bone tumour entity. Finally, the findings of the present study reflect well the high malignancy and aggressive nature of bone MFH.

Primary Fibrosarcoma and Malignant Fibrous Histiocytoma of Bone - A Comparative Ultrastructural Study: Evidence of a Spectrum of Fibroblastic Differentiation

As primary bone fibrosarcoma (FS) and malignant fibrous histiocytoma (MFH) have similar clinical, radiographic, or survival manifestations, ultrastructural and immunohistochemical studies were undertaken to determine the differentiation pathways of constituent malignant cells. Twelve cases of primary intraosseous FS and MFH were selected for this ultrastructural comparative study and were analyzed for fibroblastic or modified fibroblastic differentiation. There were 4 FS cases and 8 MFH cases, of which 5 were storiform-pleomorphic, 2 were giant cell, and 1 was myxoid type. All FS consisted of spindle fibroblasts with a prominent rough endoplasmic reticulum and Golgi apparatus, variable amounts of vimentin intermediate filaments, and extracellular collagen fibrils. The MFH were composed of a mixture of spindle and pleomorphic fibroblasts (8/8), histiofibroblasts (4/8), and myofibroblasts (3/8). Variable numbers of undifferentiated cells were found in both tumors. In conclusion, fibroblastic differentiation and collagen production was noted in all cases. The often pleomorphic histiofibroblasts present in some MFH cases most likely represent "modified fibroblasts," similar to myofibroblasts. These findings support the hypothesis that the fibroblast and its variants are the predominant cell types found in these tumors, suggesting that the diagnostic entity MFH should be classified as a pleomorphic fibrosarcoma.

Endoprosthetic reconstruction for malignant upper extremity tumors.

Between December 1980 and December 1992, 59 patients underwent 60 reconstructions with endoprostheses after resection of malignant tumors in the upper extremity. There were 32 male patients and 27 female patients, with a mean age of 33 years (range, 3-83 years). The type of reconstruction was based on the location of the primary tumor site. The histologic diagnoses included osteosarcoma, chondrosarcoma, Ewing's sarcoma, malignant fibrous histiocytoma, soft tissue sarcoma, and fibrosarcoma of bone. Most of the patients had Stage IIB disease (N = 38), as established by the Musculoskeletal Tumor Society classification. An additional six patients had metastatic tumors to the upper extremity. Twenty-seven of 59 patients died of disease progression. Two patients died of other causes (chronic leukemia, human immunodeficiency virus infection). The 30 survivors had a mean followup of 90 months (range, 60-170 months). The Musculoskeletal Tumor Society functional analysis for the patients with a minimum 2-year followup (N = 41) averaged 74%. Sixteen of the 59 (27%) patients had local complications. Problems related to mechanical failure and infection were managed successfully with second operation. Amputation was rare, occurring in three of 60 (5%) patients and was related only to local recurrence. Endoprosthetic reconstructions of the upper extremity after tumor resections have proven to be successful.

Skeletal Malignancies Among Beagles Injected With 241Am

Seventy skeletal malignancies in 44 dogs were identified among 117 beagles injected as young adults with graded dosages of approximately 0.07 to 104 kBq 241Am kg-1 and maintained for lifetime observation. All of these tumors were osteosarcomas except four fibrosarcomas of bone and four chondrosarcomas of bone. Of these 117 animals, 114 survived beyond the minimum age (of 2.79 y) for radiation-induced bone cancer, and all are now dead. An expression was derived that described the dependence of percent occurrence of bone sarcoma on skeletal radiation dose of A = 0.76 + 30D, where A = percent of dogs with skeletal malignancy within any dosage group, D = average skeletal dose (< 3 Gy) at 1 y before death (average skeletal dose was calculated to the presumed start of tumor growth, which we have taken to be 1 y before death), and 0.76 represents the lifetime percent malignant bone tumor response among 132 suitable control dogs in our colony not given any radioactivity. All dosage groups with skeletal doses of > 3 Gy at 1 y before death exhibited close to 100% occurrence and appeared to be beyond the region of linearity. Therefore, they were excluded from the derivation of this expression. Similar analysis of corresponding data for beagles given 226Ra as young adults, excluding the two highest dosage groups in which the bone tumor response was approximately 100%, yielded the expression, A = 0.76 + 4.7D, (D < 20 Gy). A ratio of the coefficients in these two expressions indicates the effectiveness at low radiation doses for bone-cancer induction of 241Am relative to 226Ra, or (30 +/- 2.6)(4.7 +/- 0.47)-1 = 6 +/- 0.8. This compares to the relative effectiveness at low radiation doses that was obtained earlier for a 239Pu:226Ra toxicity ratio of about 16 +/- 5.

The Impact of Osteonectin for Differential Diagnosis of Bone Tumors: An Immunohistochemical Approach

75 osteosarcoma at various grades of histologic differentiation, including chondroblastic and small cell variants, and 5 fibrosarcomas of bone, 5 Ewing's sarcomas, 5 malignant fibrous histiocytomas of bone, 8 chondrosarcomas, and 2 dedifferentiated chondrosarcomas, were investigated immunohistochemically for evidence of osteonectin. According to the results of our study, osteonectin is present in all osteosarcomas, with special topographic preponderance in the osteoblastic and chondroblastic variants. Evidence of osteonectin was also found in all other bone tumors we had analysed so far. In chondrosarcomas, positive reactions appeared only in the vicinity of trabeculae and in dedifferentiated areas. Thus, osteonectin cannot be regarded as a bone-specific protein. Although a high affinity for the osseous matrix is one of its undoubted features, it is therefore unsuitable for differential diagnostic purposes.

Postirradiation Fibrosarcoma of Bone: Report of 2 Cases

Postirradiation Fibrosarcoma of Bone: Report of 2 Cases

Recurrent fibrosarcoma of skull: a 35-year surgical odyssey

Fibrosarcoma of bone is said to be the rarest and least malignant of the connective tissue tumours of bone. It may originate in the periosteum or the medullary cavity of any bone. It can be successfully removed despite delay in diagnosis and repeated inadequate surgical procedures. We report a patient who presented with a recurrent fibrosarcoma of the skull who had undergone twenty operations and two courses of radiotherapy over a period of 35 years.

Definitions of osteosarcoma, chondrosarcoma, and fibrosarcoma of bone.

The current definition of osteosarcoma, based on the prescence of tumor osteoid, is unsatisfactory because it fails to identify some examples of chondroblastic, fibroblastic, and anaplastic osteosarcoma having no demonstrable tumor osteoid. The tumor cells in osteosarcoma, whether osteoblastic, chondroblastic, fibroblastic, or anaplastic, contain abundant alkaline phsophatase, whereas this enzyme is scanty or absent in condrosarcoma and fibrosarcoma. It is therefore proposed that these bone sarcomas are best defined according to the origin of the constituent tumor cells and their alkaline phosphatase content: osteosarcoma--a malignant tumor of osteoblasts (alkaline phosphatase positive); chondrosarcoma--a malignant tumor of chondroblasts (alkaline phosphatase negative); and fibrosarcoma--a malignant tumor of fibroblasts (alkaline phosphatase negative).