P. Wuisman

Analysis of mutant P53 protein in osteosarcomas and other malignant and benign lesions of bone

SummaryAlterations of tumour suppressor genes are considered crucial steps in the development of human cancers. Expressions of p53 protein, a product of the tumour suppressor gene altered most commonly in human cancers examined so far, were investigated immunohistochemically in 18 osteosarcomas and 40 other malignant and benign lesions of bone. A monoclonal antibody clone PAb240, which recognizes a common conformational epitope of mutant p53 proteins, stained nuclei of tumour cells in 12 of 18 osteosarcomas (67%). Six tumours (33%) particularly showed positive immunoreactions in more than half of the tumour cells. PAb240 also stained tumour cells in a small number of other malignant bone tumours, such as malignant fibrous histiocytoma, chondrosarcoma, and Ewings sarcomas. Furthermore, a small number of cells of giant-cell tumours were positively stained. In contrast, PAb240 was completely negative in 21 benign bone tumours and reactive lesions examined. Another monoclonal antibody clone PAb1801, which reacts with both wild- and mutant-type p53 protein, reacted in nuclei of tumour cells of 7 osteosarcomas (39%). Most of those also reacted with PAb240. PAb1801 was expressed much more frequently in other malignant bone tumours and giant-cell tumours. In addition, PAb1801 showed intranuclear positive reactions in tumour cells of a benign chondroblastoma, and reactive cells such as actively proliferating preosteoblasts in a myositis ossificans and osteoclast-like giant cells in a giantcell tumour. The immunoelectron-microscopic observation that p53 protein was localized in euchromatic areas of nuclei of osteosarcoma cells supported the specificity of immunoreaction for p53 protein, indicating an active role of p53 protein in the regulation of DNA synthesis and transcription. These findings suggest that point mutation of the p53 gene is frequently involved in the development of osteosarcomas. PAb240 may be a useful tool not only in screening point mutations of the p53 gene in osteosarcomas but also in the differential diagnosis between osteosarcomas and reactive bone-forming lesions. Expressions of mutant p53 protein were not correlated with any clinical or pathological factors examined, although the results should be confirmed in studies of a large number of osteosarcomas.

Chondroblastoma of bone : a clinical, radiological, light and immunohistochemical study

This is a retrospective study of 70 patients with chondroblastoma treated between 1973 to 2000. Of these 70 patients, 53 had their primary procedure performed at our unit in the form of an intralesional curettage. The purpose of this study was to determine the rates of recurrence and the functional outcomes following this technique. Factors associated with aggressive tumour behaviour were also analysed. The patients were followed up for at least 22 months, up to a maximum of 27 years. 6 out of these 53 cases (11. 3%) had a histologically proven local recurrence. Three patients underwent a second intralesional curettage procedure and had no further recurrences. Two patients had endoprosthetic replacement of the proximal humerus and one patient underwent a below knee amputation following aggressive local recurrences. One patient had the rare malignant metastatic chondroblastoma and died eventually. The mean MSTS score was 94. 1%. We conclude that meticulous primary intralesional curettage without any additional procedure can achieve low rates of local recurrence and excellent long-term functional results.The clinical and morphological findings of 53 chondroblastomas in the files of the Bone Tumour Registry of Westphalia are presented. The mean age of all patients was 19.2 years. The male-to-female ratio was 1.5∶1. Forty-two of the tumours (79.8%) were located in the long tubular bones and short tubular bones of the hands and were closely related to the growth plate. Six cases (11.3%) were found in the flat bones, 4 cases (7.5%) in the tarsal bones and 1 case (1.9%) in the craniofacial bones. The characteristic radiological feature of 44 investigated lesions was a mostly eccentric radiolucency with a geographic pattern of bone destruction and matrix calcifications. Periosteal reaction was evident in 9% of the cases. Most tumours demonstrate the typical morphological features of chondroblastoma, but 3 cases resembled a giant cell tumour. In 2 cases a haemangio-pericytomalike growth pattern was observed. Nine of the tumours had an aneurysmal bone cyst-like component. Vascular invasion was seen in 1 case. Immunohistochemically most cells in 30 of the cases and fetal chondroblasts in 3 cases were strongly positive with vimentin and S-100 protein. Collagen type II was positive in the chondroid matrix of the tumours and in fetal cartilage tissue; collagen type VI was present focally around individual tumour cells and was always seen in the chondroid matrix of the lesions and in fetal cartilage. These findings support the cartilaginous nature of these tumours. In paraffin sections, 46.6% of the cases revealed a distinct positive reaction of some tumour cells with the monoclonal cytokeratin antibody KL1 (molecular weight 55–57 kDa). Only 4 of them demonstrated a coexpression with the other monoclonal cytokeratin anti-body CK (clone MNF 116, molecular weight 45–56.5 kDa). In paraffin sections all fetal chondroblasts were negative with both cytokeratin antibodies. Frozen sections of 3 tumours showed a strong positive reaction with both cytokeratin antibodies in many chondroblasts, indicating an “aberrant” cytokeratin expression. Osteoclast-like giant cells stained positive with leucocyte-common antigen (LCA) and with the macrophage-associated antibody KP1, but were negative with the other macrophage-associated antibody MAC 387. Recurrence rate was 10.7%. The clinical course of all tumours was benign.The clinical and morphological findings of 53 chondroblastomas in the files of the Bone Tumour Registry of Westphalia are presented. The mean age of all patients was 19.2 years. The male-to-female ratio was 1.5∶1. Forty-two of the tumours (79.8%) were located in the long tubular bones and short tubular bones of the hands and were closely related to the growth plate. Six cases (11.3%) were found in the flat bones, 4 cases (7.5%) in the tarsal bones and 1 case (1.9%) in the craniofacial bones. The characteristic radiological feature of 44 investigated lesions was a mostly eccentric radiolucency with a geographic pattern of bone destruction and matrix calcifications. Periosteal reaction was evident in 9% of the cases. Most tumours demonstrate the typical morphological features of chondroblastoma, but 3 cases resembled a giant cell tumour. In 2 cases a haemangio-pericytomalike growth pattern was observed. Nine of the tumours had an aneurysmal bone cyst-like component. Vascular invasion was seen in 1 case. Immunohistochemically most cells in 30 of the cases and fetal chondroblasts in 3 cases were strongly positive with vimentin and S-100 protein. Collagen type II was positive in the chondroid matrix of the tumours and in fetal cartilage tissue; collagen type VI was present focally around individual tumour cells and was always seen in the chondroid matrix of the lesions and in fetal cartilage. These findings support the cartilaginous nature of these tumours. In paraffin sections, 46.6% of the cases revealed a distinct positive reaction of some tumour cells with the monoclonal cytokeratin antibody KL1 (molecular weight 55–57 kDa). Only 4 of them demonstrated a coexpression with the other monoclonal cytokeratin anti-body CK (clone MNF 116, molecular weight 45–56.5 kDa). In paraffin sections all fetal chondroblasts were negative with both cytokeratin antibodies. Frozen sections of 3 tumours showed a strong positive reaction with both cytokeratin antibodies in many chondroblasts, indicating an “aberrant” cytokeratin expression. Osteoclast-like giant cells stained positive with leucocyte-common antigen (LCA) and with the macrophage-associated antibody KP1, but were negative with the other macrophage-associated antibody MAC 387. Recurrence rate was 10.7%. The clinical course of all tumours was benign.

Juvenile Intracortical Adamantinoma of the Tibia with Predominant Osteofibrous Dysplasia-Like Features

In view of the still disputed relationship between adult adamantinoma and osteofibrous dysplasia in children, a unique case of adamantinoma, indicating a direct relationship between the two lesions, is presented with a review of the literature. The patient was a six-year-old boy who complained of pain and swelling in the left lower leg. Roentgenographs showed a loculate osteolysis surrounded by sclerosis within the cortex of the tibial shaft that would be typical of osteofibrous dysplasia. Although an osteofibrous-dysplastic component predominated histologically, some small islands of epithelial cells were scattered throughout the lesion. Immunohistochemically, the tumor cells of these epithelial islands gave a constant positive reaction for cytokeratin as well as vimentin, while the stromal cells in the osteofibrous dysplasia-like lesion were positive for vimentin only. This type of lesion is recorded in the Bone Tumor Registry of Westphalia at a rate of 8.3% for osteofibrous dysplasia, and of 25% for adamantinoma. A review of the literature, yielding reports with remarkable uniformity on 14 cases beyond the present one, suggests the existence of a separate clinicopathologic entity to be called juvenile intracortical adamantinoma with predominant osteofibrous dysplasia-like features, and which might be a regressing form of adamantinoma specific in childhood.

Prognostic implication of immunodetection of P glycoprotein in Ewing's sarcoma

Increased expression of P glycoprotein is associated with multidrug resistance in many cell lines. P glycoprotein has been detected in different human tumors. To assess the implication of multidrug resistance in the prognosis of Ewings sarcoma the expression of P glycoprotein was studied immunohistochemically in pre- and post-therapeutic tumor tissues of 21 cases treated according to the CESS 81 or 86 protocol. The response to chemotherapy was evaluated histologically. Formalin-fixed, paraffin-embedded and fresh frozen sections were immunostained with a monoclonal antibody to P glycoprotein, clone JSB 1, using the double APAAP method. P glycoprotein was detected in 12 cases of 21 (57%) in either pre- or postchemotherapy tumor tissues. From the 21 cases 8 revealed a good morphological response to chemotherapy (33%); 10 of the 13 non-responders were positive for P glycoprotein (77%), but only 2 of the 8 responders (25%). The difference was statistically significant (P<0.05). Comparing P glycoprotein expression with the clinical outcome, we found that 7 of 12 positive cases had died (58%). From the negative cases only 3 of 9 had died (33%). However, judged by the the Kaplan Meyer life tables, these data were not significant. In conclusion our results suggest that the immunodetection of P glycoprotein indicates a poor response to chemotherapy and probably a bad clinical outcome for Ewings sarcoma patients.

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 Ewings 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.

Histogenesis of clear cell chondrosarcoma. An immunohistochemical study with osteonectin, a non-collagenous structure protein.

SummaryThe histogenesis of clear cell chondrosarcoma is still unclear: Apart from typical clear cell tumor areas, extensive production of woven bone formation suggests within the clear cell cartilagineous stroma is an intriguing phenomenon. Three cases of clear cell chondrosarcoma documented in the Bone Tumor Registry of Westphalia were examined for their patterns of osteonectin expression, and compared with other bone tumors of either osseous or cartilagineous origin, and with normal cartilage tissue. Found predominantly in osseous structures, the protein osteonectin takes part in the formation of new bone. The three clear cell chondrosarcomas showed a strong immunoexpression of osteonectin in clear cell, chondroid and in osseous tumor areas. Similarly, evidence of osteonectin was also found in osteoblastic and in chondroblastic osteosarcomas as well as in osteoblastomas. In contrast, osteonectin could not be demonstrated in the chondrosarcomas and mesenchymal chondrosarcomas from our registry that were analysed for comparison, and was found only minimally in the fibroblastic areas of dedifferentiated chondrosarcomas. The chondroblastic tumor components were always negative. There was no immunoexpression of osteonectin either in fetal or adult intervertebral disc tissue. The present immunohistochemical study of osteonectin has distinctly separated clear cell chondrosarcoma from the other variants of chondrosarcoma, and aptly verified the specificity of this entity. Moreover, the study would call for further histogenetic evaluation of clear cell chondrosarcoma, since the pattern of osteonectin expression in that tumor seems to indicate an osteogenic rather than a chondrogenic origin.

(Sub)periosteal Ewing's sarcoma of bone

SummaryEwings sarcoma is a small malignant round-cell tumour that arises from mesenchymal cells, predominantly in the medullary cavity of bone. In exceptional cases it originates in the soft tissues and subsequently invades the underlying bone. A (sub)periosteal origin of Ewings sarcoma is a very rare condition: only a few cases have been published so far. Three cases of (sub)periosteal Ewings sarcoma, having received neoadjuvant chemotherapy and radiation therapy as well as wide excision, are reported.

Spindle Cell (Leiomyomatous) Rhabdomyosarcoma, a Rare Variant of Embryonal Rhabdomyosarcoma

A rare case of the leiomyomatous variant of embryonal rhabdomyosarcoma is reported. A 13-year-old boy presented with a recurrent painless mass on the ventral side of the right forefoot. Microscopically, the tumor consisted of spindle-shaped and round tumor cells in a fascicular or storiform, focally hemangiopericytoma-like growth pattern. The cytoplasm of the spindle-shaped tumor cells was eosinophilic and fibrillary, in some areas resembling smooth muscle cells. Immunohistologically, all tumor cells were vimentin-positive, most of them also stained with antibodies to desmin and muscle specific actin (MSA). In addition, many tumor cells showed a co-expression of alpha-sarcomeric actin and myoglobin. All tumor cells were negative with alpha-smooth muscle actin. Two years after surgical treatment and chemotherapy the patient is well with no evidence of distant metastases. The clinicopathological features and differential diagnostic problems are discussed.

High malignant surface osteosarcoma arising at the site of a previously treated aneurysmal bone cyst.

A patient who developed a high malignant surface osteosarcoma at the site of a previously treated aneurysmal bone cyst is reported. The patient developed the osteosarcoma 4 years after complete curettage and bone-grafting of the cyst. The clinical, radiological and light microscopic features of this case are described. A causal relationship between the preexisting aneurysmal bone cyst and osteosarcoma is discussed, but seems to be unlikely.

Case report 669

A case is presented of an 18-year-old women who suffered pain and swelling after intraarterial cisplatin chemotherapy for osteosarcoma of the left fibula. Radiological studies showed minimal changes at the metadiaphyseal portion of the left tibia. Bone scans and MR studies were highly suggestive of necrosis of bone and muscle of the proximal end of the tibia. Multiple biopsies of the tibia at the time of excision and 2 years later showed histological features consistent with a slowly healing osteonecrosis of bone. Review of the literature reported transient pain and swelling after intraarterial chemotherapy but did not demonstrate the association with necrosis of bone and muscle. It can be anticipated that as intraarterial chemotherapy of malignant tumors of bone and soft tissues becomes more widely used, these complications will be observed more frequently.