Three to six tissue specimens for histopathological analysis are most accurate for diagnosing periprosthetic joint infection

AIMS

The aim of this study was to evaluate the optimal deep tissue specimen sample number for histopathological analysis in the diagnosis of periprosthetic joint infection (PJI).

METHODS

In this retrospective diagnostic study, patients undergoing revision surgery after total hip or knee arthroplasty (n = 119) between January 2015 and July 2018 were included. Multiple specimens of the periprosthetic membrane and pseudocapsule were obtained for histopathological analysis at revision arthroplasty. Based on the Infectious Diseases Society of America (IDSA) 2013 criteria, the International Consensus Meeting (ICM) 2018 criteria, and the European Bone and Joint Infection Society (EBJIS) 2021 criteria, PJI was defined. Using a mixed effects logistic regression model, the sensitivity and specificity of the histological diagnosis were calculated. The optimal number of periprosthetic tissue specimens for histopathological analysis was determined by applying the Youden index.

RESULTS

Based on the EBJIS criteria (excluding histology), 46 (39%) patients were classified as infected. Four to six specimens showed the highest Youden index (four specimens: 0.631; five: 0.634; six: 0.632). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of five tissue specimens were 76.5% (95% confidence interval (CI) 67.6 to 81.4), 86.8% (95% CI 81.3 to 93.5), 66.0% (95% CI 53.2 to 78.7), and 84.3% (95% CI 79.4 to 89.3), respectively. The area under the curve (AUC) was calculated with 0.81 (as a function of the number of tissue specimens). Applying the ICM and IDSA criteria (excluding histology), 40 (34%) and 32 (27%) patients were categorized as septic. Three to five specimens had the highest Youden index (ICM 3: 0.648; 4: 0.651; 5: 0.649) (IDSA 3: 0.627; 4: 0.629; 5: 0.625).

CONCLUSION

Three to six tissue specimens of the periprosthetic membrane and pseudocapsule should be collected at revision arthroplasty and analyzed by a pathologist experienced and skilled in interpreting periprosthetic tissue.Cite this article: Bone Joint J 2023;105-B(2):158-165.

Results in the surgical treatment of aneurysmal bone cysts - A retrospective data analysis

BACKGROUND

Aneurysmal bone cysts (ABC) are benign tumors mostly occurring in children and young adults. Different open and minimal invasive surgical approaches have been proposed for the treatment of ABCs and yet no consensus is defined to date. The aim of this study was to retrospectively review data of a large single center series of ABCs with patients treated by open curettage with or without filling of the cavity or en-bloc resection. Questions/purposes We asked: (1) What was the local recurrence rate of ABC after surgical treatment at our institution? (2) What were positive or negative predictors for local recurrence? (3) Was there a benefit from adjuvant burring, phenolization or filling, respectively? (4) Where there changes in recurrence free survival in different time periods of primary surgery?

METHODS

By retrospective data analysis of the Vienna Bone and Soft Tissue Tumor Registry, 123 patients surgically treated for primary aneurysmal bone cysts were identified. After exclusion of 33 patients (27%) due to a postoperative follow up below one year, 90 patients who were treated for primary ABCs between 1986 and 2009 were evaluated. These included 50 males and 40 females with a mean age of 16 years (SD 10 years; range: 2 to 51 years). The mean follow-up was 99 months. (SD 72 months, range: 13 to 329 months) RESULTS: Curettage was performed in 84 patients, while 45 patients received adjuvant phenolization. Local recurrence occurred in 28 patients after a mean time of 16 months, with a corresponding local recurrence free survival (RFS) of 83% after one year, 77% after 2 years and 66% after 5 years. ABCs located in hands and feet (p=0.044) showed a superior RFS, while younger patients (p=0.001) displayed an inferior RFS. Regarding adjuvant surgical techniques, mechanical cavity burring (p=0.004) and filling with autologous cancellous bone graft (p=0.024) showed protective effects on RFS. Patients treated between 1986 and 1999 (n=47) had a higher RFS than patients treated between 2000 and 2009 (n=43, p=0.011), as surgeons and surgical indications changed over time.

CONCLUSION

Although curettage, burring, phenolization and reconstruction with bone grafts came with a relatively high risk of local recurrence, open surgery is still justified in aggressively growing ABCs of critical localizations.

LEVEL OF EVIDENCE

IV; therapeutic study.

Diagnostic accuracy of neutrophil counts in histopathological tissue analysis in periprosthetic joint infection using the ICM, IDSA, and EBJIS criteria

Aims

Histology is an established tool in diagnosing periprosthetic joint infections (PJIs). Different thresholds, using various infection definitions and histopathological criteria, have been described. This study determined the performance of different thresholds of polymorphonuclear neutrophils (≥ 5 PMN/HPF, ≥ 10 PMN/HPF, ≥ 23 PMN/10 HPF) , when using the European Bone and Joint Infection Society (EBJIS), Infectious Diseases Society of America (IDSA), and the International Consensus Meeting (ICM) 2018 criteria for PJI.

Methods

A total of 119 patients undergoing revision total hip (rTHA) or knee arthroplasty (rTKA) were included. Permanent histology sections of periprosthetic tissue were evaluated under high power (400× magnification) and neutrophils were counted per HPF. The mean neutrophil count in ten HPFs was calculated (PMN/HPF). Based on receiver operating characteristic (ROC) curve analysis and the z-test, thresholds were compared.

Results

Using the EBJIS criteria, a cut-off of ≥ five PMN/HPF showed a sensitivity of 93% (95% confidence interval (CI) 81 to 98) and specificity of 84% (95% CI 74 to 91). The optimal threshold when applying the IDSA and ICM criteria was ≥ ten PMN/HPF with sensitivities of 94% (95% CI 79 to 99) and 90% (95% CI 76 to 97), and specificities of 86% (95% CI 77 to 92) and 92% (95% CI 84 to 97), respectively. In rTKA, a better performance of histopathological analysis was observed in comparison with rTHA when using the IDSA criteria (p < 0.001).

Conclusion

With high accuracy, histopathological analysis can be supported as a confirmatory criterion in diagnosing periprosthetic joint infections. A threshold of ≥ five PMN/HPF can be recommended to distinguish between septic and aseptic loosening, with an increased possibility of detecting more infections caused by low-virulence organisms. However, neutrophil counts between one and five should be considered suggestive of infection and interpreted carefully in conjunction with other diagnostic test methods.

Cite this article: Bone Joint Res 2021;10(8):536–547.

Osteosarcoma of the jaw - experience at the Medical University Vienna and comparative study with international tumor registries

OBJECTIVES

Osteosarcoma of the jaw (OSAJ) is fundamentally different in clinical practice from its peripheral counterparts. Studies are difficult to conduct due to low incidence rates. The primary aim of this study was to provide for the first time a comprehensive retrospective analysis of the treatment concepts and outcome data of OSAJ patients treated at the University Hospital Vienna and to compare these with two recently published studies on OSAJ. The clinical study was accompanied by a biomarker study investigating the prognostic relevance of melanoma-associated antigen-A (MAGE-A) in OSAJ specimens.

METHOD

Eighteen patients were included, and their outcomes were compared to published data. Immunohistochemistry was performed with mouse monoclonal antibodies against MAGE-A. Survival rates were estimated by the Kaplan-Meyer method. The log-rank test was used to analyze potential prognostic parameters. Fisher's exact test was performed to define the significant differences between the survival rates of the current study and the DOESAK registry.

RESULTS

Disease-specific survival was 93.8% after five and 56.3% after ten years. The development of metastases (p=0.033) or relapse (p=0.037) was associated with worsened outcomes in our group as well as in the comparative group. Despite the different treatment concepts of the study groups, survival rates were comparable. MAGE-A failed to show prognostic relevance for OSAJ patients.

CONCLUSIONS

Uncertainties about the optimal treatment strategies of OSAJ patients will currently remain. Thus, prospective studies of OSAJ are needed but are only feasible in a multicenter study setting, conducted over a prolonged time period.

Uptake of 18F-FLT and 18F-FDG in primary head and neck cancer correlates with survival

The aim of the study was to determine the practicability of 18F-FLT in tumours of the head and neck area in terms of visualization, a possible correlation between FLT uptake and proliferation fraction as determined by Ki-67 immunostaining, and if tumoural FLT-uptake has a prognostic meaning, as determined by a correlation to patient survival time. Results were compared to 18F-FDG. Patients, methods: 20 patients with previously untreated lesions of the head and neck area, which were clinically highly suspicious to be malignant, underwent PET scans with 18F-FLT and 18F-FDG, a CT of the head and neck area, and a biopsy. Tumour tracer uptake was determined by standardized uptake value (SUV) normalized to body weight and /non-tumor ratios (T/N). 18F-FDG and 18F-FLT uptake were compared with histopathologic and immunohistochemical results. Results: 19 patients had malignant tumours; one patient had a benign cystadenoma (so called Warthin's tumour) of the parotid gland. One negative lesion turned out to be a malignant T1 stage squamous cell carcinoma in both PET scans, the Warthin's tumour was false positive with 18F-FDG but showed only faint uptake with 18F-FLT, resulting in a sensitivity of 95 % for both tracers. Of all lesions, maximum SUVs of 18F-FLT ranged from 1.53 to 11.70 (mean ± SD 5.81 ± 2.28) those of FDG from 2.63 to 16.50 (mean ± SD 8.91 ± 3.58), p < 0.001. 18F-FLT-T/N ranged from 0.94 to 5.85 (mean ± SD, 3.18 ± 1.21), 18F-FDG-T/N was from 0.92 to 7.50 (mean ± SD, 3.6 ± 1.74), n.s. The mean survival time was 18 months in a maximum follow up time of 36 months. A significant correlation between both PET tracers and survival was detected, but no correlation between the amount of Ki-67 positive cells and FLT. Conclusion: In head and neck cancer in the primary setting 18F-FLT does not provide additional visual information in comparison to 18F-FDG.18F-FLT uptake is inversely correlated with patient survival, as well as 18F-FDG.

Choice of High-Dose Intravenous Iron Preparation Determines Hypophosphatemia Risk

Background

Ferric carboxymaltose (FCM) and iron isomaltoside 1000 (IIM) are increasingly used because they allow correction of severe iron deficiency in a single infusion. A transient decrease in serum phosphate concentrations is a frequent side effect of FCM.

Aim

To characterize this adverse event and search for its predictors in a gastroenterology clinic patient cohort.

Methods

Electronic medical records of patients attending the University Hospital of Innsbruck were searched for the keywords ferric carboxymaltose or iron isomaltoside. Eighty-one patients with documented administration of FCM or IIM with plasma phosphate concentrations before and after treatment were included.

Results

The prevalence of hypophosphatemia (<0.8 mmol/L) increased from 11% to 32.1% after treatment with i.v. iron. The hypophosphatemia risk was greater after FCM (45.5%) compared with IIM (4%). Severe hypophosphatemia (<0.6 mmol/L) occurred exclusively after FCM (32.7%). The odds for hypophosphatemia after i.v. iron treatment were independently determined by baseline phosphate and the choice of i.v. iron preparation (FCM vs. IIM—OR = 20.8; 95% CI, 2.6–166; p = 0.004). The median time with hypophosphatemia was 41 days, but prolonged hypophosphatemia of ≥ 2 months was documented in 13 of 17 patients in whom follow-up was available. A significant increase in the phosphaturic hormone intact FGF-23 in hypophosphatemic patients shows that this adverse event is caused by FCM-induced hormone dysregulation.

Conclusion

Treatment with FCM is associated with a high risk of developing severe and prolonged hypophosphatemia and should therefore be monitored. Hypophosphatemia risk appears to be substantially lower with IIM.

C-reactive protein as a prognostic factor in patients with chordoma of lumbar spine and sacrum--a single center pilot study

Study design

This is a retrospective, diagnostic study, level IV.

Background

It appears to be necessary to identify prognostic markers for individual risk estimation for progression and survival in patients with chordoma, a rare disease. Are pre-operative serum levels of C-reactive protein (CRP) associated with disease progression and survival?

Methods

Survival rates of 24 patients (18 males, 6 females) (mean age 67 years (SD ± 16; range 20–85 years); minimum follow-up 2 years, mean follow-up 5 years (SD ± 5; range 2–19 years)) with chordoma of the lower spine and sacrum were assessed with a focus on pre-operative CRP levels.

Results

The survival rate of patients with pre-operative CRP level of >1.0 mg/dl was lower than that of patients with a CRP level <1.0 mg/dl (p = 0.01). The estimated 10-year survival of patients with pre-operative CRP values <1.0 and >1.0 mg/dl was 76 and 25 %, respectively. CRP remained as an independent survival factor (p = 0.025; CI 95 % 1.0–2.6) in multivariable analysis.

Conclusions

Pre-operative CRP levels appear to be a biomarker for disease-specific survival in patients with chordoma of the lumbar spine and sacrum. A validation of our finding with larger cohorts and integration of putative risk factor would further elucidate CRP a surrogate for tumor progression.

Recurrence rate and progression of chondrosarcoma is correlated with heat shock protein expression

Heat shock proteins (HSPs) are involved in tumour immunity, and are correlated with survival and drug resistance in numerous types of cancer. The present study investigated the expression of HSPs and multiple drug resistance (MDR) in human chondrosarcoma. HSP and P-glycoprotein (the MDR1 gene product) expression was evaluated by immunohistochemical analysis of paraffin-embedded sections obtained from 37 patients with chondrosarcoma (19 male and 18 female; aged 33–85 years; mean age, 48.5 years). HSP73 and 90 were significantly overexpressed in patients with local recurrence: HSP73 was expressed in 7/7 patients (100%) with local recurrence and 9/18 patients (50%) without recurrence (P<0.02), while HSP90 was expressed in all patients with recurrence but only 8/18 (44%) without recurrence (P<0.02). A marked association was also identified between HSP expression and survival. HSP72 and 73 were significantly overexpressed in tumours from patients who succumbed to the disease (all positive for HSP72 and 73; P<0.05). No differences were observed between HSP27, 73 or 90-positive or -negative tumours according to age or gender. In addition, HSP72 expression was correlated with differentiation of the tumours (P<0.02). These results indicate that HSP72, 73 and 90 may function as novel prognostic markers for chondrosarcoma, and initiate further studies regarding the use of such markers for the identification of patients with poor prognosis.

Vascularization of primary and secondary ossification centres in the human growth plate

Background

The switch from cartilage template to bone during endochondral ossification of the growth plate requires a dynamic and close interaction between cartilage and the developing vasculature. Vascular invasion of the primarily avascular hypertrophic chondrocyte zone brings chondroclasts, osteoblast- and endothelial precursor cells into future centres of ossification.

Vascularization of human growth plates of polydactylic digits was studied by immunohistochemistry, confocal-laser-scanning-microscopy and RT-qPCR using markers specific for endothelial cells CD34 and CD31, smooth muscle cells α-SMA, endothelial progenitor cells CD133, CXCR4, VEGFR-2 and mesenchymal progenitor cells CD90 and CD105. In addition, morphometric analysis was performed to quantify RUNX2⁺ and DLX5⁺ hypertrophic chondrocytes, RANK⁺ chondro- and osteoclasts, and CD133⁺ progenitors in different zones of the growth plate.

Results

New vessels in ossification centres were formed by sprouting of CD34⁺ endothelial cells that did not co-express the mature endothelial cell marker CD31. These immature vessels in the growth plate showed no abluminal coverage with α-SMA⁺ smooth muscle cells, but in their close proximity single CD133⁺ precursor cells were found that did not express VEGFR-2, a marker for endothelial lineage commitment. In periosteum and in the perichondrial groove of Ranvier that harboured CD90⁺/CD105⁺ chondro-progenitors, in contrast, mature vessels were found stabilized by α-SMA⁺ smooth muscle cells.

Conclusion

Vascularization of ossification centres of the growth plate was mediated by sprouting of capillaries coming from the bone collar or by intussusception rather than by de-novo vessel formation involving endothelial progenitor cells. Vascular invasion of the joint anlage was temporally delayed compared to the surrounding joint tissue.

Bcl-2 correlates with localization but not outcome in human osteosarcoma

bcl-2 is a member of the bcl-2 family that inhibits apoptosis, plays a crucial role in cell viability and is expressed in various types of tumors. With respect to inconsistent results in previous studies, the aim of the present study was to generate a clear hypothesis with regards to the value of bcl-2 expression as a predictive or prognostic factor in human osteosarcoma. The expression of bcl-2 was examined immunohistochemically in 49 patients with high-grade osteosarcoma and the results were correlated with localization, histological response to chemotherapy, survival and the occurrence of metastases. In patients with osteosarcoma, 21/49 cases (43%) were positive for bcl-2 expression and the remaining cases were negative. A significantly higher expression of bcl-2 was observed in central tumors located in the pelvis (83 vs. 37% positive; P<0.05). The bcl-2 expression status revealed no statistically significant correlation with response to chemotherapy, with 57% of patients with bcl-2-positive tumors showing a good response and 43% showing a poor response. No significant difference was observed when comparing survival or occurrence in bcl-2-positive and -negative tumors. In conclusion, the results of the present study indicate that, despite higher bcl-2 expression in central osteosarcoma, the expression in high-grade osteosarcoma is not a reliable prognostic or predictive marker.

Altered matrix mineralization in a case of a sclerosing osteosarcoma

Little is known about the tumor matrix mineralization of highly sclerotic osteosarcoma. We used quantitative backscattered electron imaging (qBEI) to determine the Bone mineralization density distribution (BMDD) of a highly sclerosing osteosarcoma of the proximal tibia as well as adjacent normal bone of a 10-year-old girl following chemotherapy according to the EURAMOS-1 protocol. Data were compared to recently published normative reference data for young individuals. Backscattered electron imaging of the tumor region revealed a dense accumulation of mineralized tumor bone matrix (up to 90% of the medullar space). The BMDD was shifted tremendously towards higher matrix mineralization (CaMean +18.5%, CaPeak +22.5%, CaHigh +100 fold) compared to normal bone. Additionally the BMDD became much wider, indicating a higher heterogeneity in mineralization (CaWidth +40%). In contrast to lamellar bone, which mineralizes via a mineralization front, the mineralization of the tumor matrix starts by randomly distributed spots of mineral clusters fusing together to a highly mineralized non-lamellar bone matrix. We also found an altered BMDD of the patient's normal bone when compared with the reference BMDD of young individuals. In conclusion this high radiodensity region of the sclerosing sarcoma is not only due to the high amount of tumor matrix but also to its high mineralization density. Chemotherapy may lead to altered matrix mineralization of normal bone due to suppression of bone turnover. The mechanism of matrix mineralization in a sclerosing osteosarcoma warrants further studies.

Osteoarthritis: histology and pathogenesis

Osteoarthritis is the most common joint disease, affecting over 60 % of the elderly population, leading to incapacity of movement. The primary form is usually oligoarticular. In case of an underlying systemic disease or local injury, the cartilage destruction is considered as secondary osteoarthritis. The pathogenesis of primary osteoarthritis suggests an intrinsic disease of cartilage in which biochemical and metabolic alterations result in its breakdown. Within the last decades, different models were established concentrating on joint structures such as bones or ligaments. Changes of the subchondral bone were found to precede cartilage damage, suggesting a primary alteration of the subchondral region. Other studies concentrated on the metabolic activity of chondrocytes in healthy cartilage of patients with osteoarthritis. The precise event that leads to these changes is still not clear. This review concentrates on the histological features in the course of the disease and provides a summary on different pathogenetic risk factors.

Expression of platelet-derived growth factor-alpha receptor in human osteosarcoma is not a predictor of outcome

AIMS

The aims of this study were to examine the prognostic relevance of platelet-derived growth factor-α receptor (PDGFRA) expression in human osteosarcomas and to evaluate the mutation status of exon 12 and exon 18 of the PDGFRA gene.

METHODS

PDGFRA expression was examined in 100 human osteosarcomas by immunohistochemistry using paraffin embedded tumour tissues, and capillary sequencing of genomic DNA was performed to search for mutations in exons 12 and 18 of the PDGFRA gene.

RESULTS

Ninety-six osteosarcomas showed PDGFRA expression ranging from 4% to 90% (mean 40%, median 37.5%, SD 27.11%). Furthermore, DNA sequence of exon 12 and exon 18 of the PDGFRA gene were not altered in 40 tumours with high PDGFRA expression. Overall and disease-free survival analysis did not reveal any differences between osteosarcoma patients with high PDGFRA expression and patients with low PDGFRA expression.

CONCLUSIONS

The protein expression is not linked to mutations in exon 12 or exon 18 of PDGFRA gene. Therefore, treatment modalities based on the suppression of PDGFRA tyrosine kinase activity may need further investigation. PDGFRA expression is not a prognostic marker for osteosarcoma patients.

[Squamous cell carcinoma in Dupuytren's disease--a case report]

Squamous cell carcinoma in the palm is an extremely rare entity. In the following case report we describe the occurrence of a squamous cell carcinoma in the presence of Dupuytren's disease. A 49-year-old man was operated on the right hand for ulcerating Dupuytren's disease. A squamous cell carcinoma was diagnosed by performing obtaining a fast section intraoperatively. The patient had an invasive, highly differentiated keratinizing squamous cell carcinoma. The lesion was resected together with the Dupuytren lesion and the defect covered with a full-thickness graft. Postoperatively the patient was irradiated. He is free of recurrence for three years now. To our knowledge, this is the first published report of a squamous cell carcinoma in the presence of Dupuytren's disease.

Diffusion-weighted magnetic resonance imaging of head and neck squamous cell carcinomas

OBJECTIVE

To evaluate whether diffusion-weighted imaging (DWI) is a reliable technique to quantify microstructural differences between head and neck squamous cell carcinomas (SCC) and tumour-free soft tissue.

MATERIALS AND METHODS

DWI was obtained from 20 patients with histologically proven, untreated head and neck SCC. DWI was acquired using a diffusion-weighted, navigated echo-planar imaging sequence with a maximum b-value of 800 s/mm2. For an objective assessment of image quality, the signal-to-noise ratio (SNR) was calculated. Microstructural differences between vital tumour tissue and tumour-free soft tissue were quantified by calculating the apparent-diffusion-coefficients (ADC) on a pixel by pixel method.

RESULTS

Echo-planar DWI provided good image quality in all patients (mean SNR 18.4). The mean ADC of SCC, (0.64+/-0.28 x 10(-3) mm2/s), was significantly (P<0.0001) lower than that of the tumour-free soft tissue, (2.51+/-0.82 x 10(-3) mm2/s).

CONCLUSION

DWI is a reliable diagnostic tool to quantify the microstructural differences between vital tumour tissue and tumour-free soft tissue in patients with head and neck SCC.

Cinacalcet decreases bone formation rate in hypercalcemic hyperparathyroidism after kidney transplantation

BACKGROUND/AIMS

Cinacalcet reduces serum calcium in kidney transplant recipients with hypercalcemic hyperparathyroidism. Its effect on bone, however, has not been investigated in this population.

METHODS

We prospectively examined bone turnover, histomorphometry and density as well as serum bone biomarkers in 10 transplant recipients before and after treatment with cinacalcet.

RESULTS

After 18-24 months of treatment with cinacalcet, bone formation decreased in 7, increased in 2, and remained zero in 1 patient (p = 0.11). Trabecular bone volume was maintained. Trabecular number decreased (p = 0.03), but trabecular thickness was unchanged (p = 0.17). Osteoid decreased (p = 0.02) and osteoblast surface increased (p = 0.02). Bone mineral density of the femur remained stable in 1 patient, decreased in 2 patients, but increased in 7 patients (p = 0.153). Serum calcium concentration (p = 0.005), iPTH (p = 0.01) and calcitonin concentration decreased (p = 0.03), while 25(OH) vitamin D(3) increased (p = 0.02). No fractures were reported. Graft function remained stable.

CONCLUSION

While cinacalcet might decrease bone formation rate, it did not change bone volume, and bone mineral density of the femur increased. Therefore, the use of cinacalcet in hypercalcemic hyperparathyroidism might be safe with regard to the bone disease present after kidney transplantation.

In vitro determination of biomechanical properties of human articular cartilage in osteoarthritis using multi-parametric MRI

The objective of this study was to evaluate the correlations between MR parameters and the biomechanical properties of naturally degenerated human articular cartilage. Human cartilage explants from the femoral condyles of patients who underwent total knee replacement were evaluated on a micro-imaging system at 3T. To quantify glycosaminoglycan (GAG) content, delayed gadolinium-enhanced MRI of the cartilage (dGEMRIC) was used. T(2) maps were created by using multi-echo, multi-slice spin echo sequences with six echoes: 15, 30, 45, 60, 75, and 90 ms. Data for apparent diffusion constant (ADC) maps were obtained from pulsed gradient spin echo (PGSE) sequences with five b-values: 10.472, 220.0, 627.0, 452.8, 724.5, and 957.7. MR parameters were correlated with mechanical parameters (instantaneous (I) and equilibrium (Eq) modulus and relaxation time (tau)), and the OA stage of each cartilage specimen was determined by histological evaluation of hematoxylin-eosin stained slices. For some parameters, a high correlation was found: the correlation of T(1Gd) vs Eq (r=0.8095), T(1Gd) vs I/Eq (r=-0.8441) and T(1Gd) vs tau (r=0.8469). The correlation of T(2) and ADC with selected biomechanical parameters was not statistically significant. In conclusion, GAG content measured by dGEMRIC is highly related to the selected biomechanical properties of naturally degenerated articular cartilage. In contrast, T(2) and ADC were unable to estimate these properties. The results of the study imply that some MR parameters can non-invasively predict the biomechanical properties of degenerated articular cartilage.

Uptake of (18)F-FLT and (18)F-FDG in primary head and neck cancer correlates with survival

The aim of the study was to determine the practicability of (18)F-FLT in tumours of the head and neck area in terms of visualization, a possible correlation between FLT uptake and proliferation fraction as determined by Ki-67 immunostaining, and if tumoural FLT-uptake has a prognostic meaning, as determined by a correlation to patient survival time. Results were compared to (18)F-FDG.

PATIENTS, METHODS

20 patients with previously untreated lesions of the head and neck area, which were clinically highly suspicious to be malignant, underwent PET scans with (18)F-FLT and (18)F-FDG, a CT of the head and neck area, and a biopsy. Tumour tracer uptake was determined by standardized uptake value (SUV) normalized to body weight and /non-tumor ratios (T/N). (18)F-FDG and (18)F-FLT uptake were compared with histopathologic and immunohistochemical results.

RESULTS

19 patients had malignant tumours; one patient had a benign cystadenoma (so called Warthin's tumour) of the parotid gland. One negative lesion turned out to be a malignant T1 stage squamous cell carcinoma in both PET scans, the Warthin's tumour was false positive with (18)F-FDG but showed only faint uptake with (18)F-FLT, resulting in a sensitivity of 95 % for both tracers. Of all lesions, maximum SUVs of (18)F-FLT ranged from 1.53 to 11.70 (mean +/- SD 5.81 +/- 2.28) those of FDG from 2.63 to 16.50 (mean +/- SD 8.91 +/- 3.58), p < 0.001. (18)F-FLT-T/N ranged from 0.94 to 5.85 (mean +/- SD, 3.18 +/- 1.21), (18)F-FDG-T/N was from 0.92 to 7.50 (mean +/- SD, 3.6 +/- 1.74), n.s. The mean survival time was 18 months in a maximum follow up time of 36 months. A significant correlation between both PET tracers and survival was detected, but no correlation between the amount of Ki-67 positive cells and FLT.

CONCLUSION

In head and neck cancer in the primary setting (18)F-FLT does not provide additional visual information in comparison to (18)F-FDG.(18)F-FLT uptake is inversely correlated with patient survival, as well as (18)F-FDG.

Expression of platelet-derived growth factor-AA and platelet-derived growth factor-alpha receptor in ameloblastomas

BACKGROUND

Platelet-derived growth factor (PDGF)-AA isoform and its receptor, PDGF-alpha receptor (PDGFRA) regulate tooth development and growth. We investigated the expression of both proteins in ameloblastomas, to contribute the understanding of the potential role of the PDGF/PDGFR system in this odontogenic neoplasm.

METHOD

Twenty-nine specimens of ameloblastoma were analyzed for PDGF-AA and PDGFRA expression using immunohistochemistry. The proliferation activity was investigated with the MIB-1 antibody. Additionally, capillary sequencing of genomic DNA was performed to search for mutations in therapeutically relevant exons 12 and 18 of the PDGFRA gene.

RESULTS

PDGF-AA and PDGFRA expression were detectable in all cases with the exception of one tumor. However, protein expression levels did neither correlate with each other nor with MIB-1 expression. Unicystic ameloblastomas did not differ from solid tumors with regard to PDGF-AA, PDGFRA, and MIB-1 expression. One tumor revealed a somatic mutation of exon 12 of the PDGFRA gene.

CONCLUSION

PDGF-AA and PDGFRA proteins are regularly expressed in variable levels in ameloblastomas, and somatic mutations of exon 12 and exon 18 of the PDGFRA gene are rare findings.

Low-turnover bone disease in hypercalcemic hyperparathyroidism after kidney transplantation

Hypercalcemia in persistent secondary hyperparathyroidism after kidney transplantation is considered to result from increased bone resorption. Bone biopsies' studies, however, have never been performed in these patients. Bone biopsies after double tetracycline labeling were obtained from 17 patients with hypercalcemic hyperparathyroidism and an estimated glomerular filtration rate > 30 mL/min/1.73 m2. Serologic bone markers, calcitriol, intact fibroblast growth factor-23 (iFGF-23), and serum and 24h urine concentration of calcium and phosphate were measured in all patients. Tubular maximum for phosphate corrected for GFR (TmP/GFR), and the fractional excretion of calcium (FeCa) were calculated. High-turnover renal osteodystrophy (ROD) was present in nine and low-turnover ROD in eight patients. The bone formation rate was significantly associated with bone alkaline phosphatase, c-telopeptide and osteocalcin. In patients with high turnover ROD, osteocalcin was also significantly higher than in patients with decreased bone formation. The FeCa was normal or below normal in 14/17 patients. TmP/GFR was below normal in all patients. Neither intact PTH nor iFGF-23 was associated with TmP/GFR, FeCa or any histomorphometric bone parameter. We conclude that hypercalcemia of posttransplant hyperparathyroidism can be associated with high or low turnover bone disease. Decreased calcium excretion suggests an additive tubular effect on hypercalcemia.

Livin and Bcl-2 expression in high-grade osteosarcoma

AIMS

The evaluation of prognosis in patients with osteosarcoma is limited to clinical parameters. Although numerous molecular markers have been studied, none are currently in routine clinical use. The aim of this study was to determine if Livin and Bcl-2, acting as antiapoptotic proteins through different mechanisms, are expressed in osteosarcoma, and whether they can be used as prognostic markers in human osteosarcoma.

METHODS

Tumor specimens of 29 patients with high-grade central osteosarcoma, with complete clinical follow-up for a minimum of 5 years, were studied. The localization and distribution of Livin and Bcl-2 were investigated using immunohistochemistry. Results were correlated with the histological response to chemotherapy, 5-year disease-free and 5-year overall survival.

RESULTS

Bcl-2 was expressed only in the cytoplasm of 16/29 cases and there was no statistically significant correlation between expression and any of the studied parameters. Livin was detected in 17/29 cases, in the cytoplasm of all 17 and in the nucleus of only 3 cases. Nuclear expression was significantly correlated with a decreased overall survival (P < 0.0002) compared with those patients without nuclear expression.

CONCLUSIONS

The results of this study indicate that Bc1-2 and Livin are highly expressed in osteosarcoma cells and that possibly, the evaluation of nuclear Livin expression might be a useful prognostic marker in osteosarcoma.

Expression of c-kit in human osteosarcoma and its relevance as a prognostic marker

AIMS

To examine the prognostic relevance of c-kit expression in human osteosarcomas and to evaluate the mutation status in exon 9 and exon 11 of the c-kit gene.

METHODS

c-kit expression was examined in 100 human osteosarcomas by immunohistochemistry using paraffin embedded tumour tissues, and capillary sequencing of genomic DNA was performed to search for mutations in exons 9 and 11 of the c-kit gene.

RESULTS

20 osteosarcomas showed c-kit expression ranging from 5% to 90% (mean 5.9%; SD 16.74%). Furthermore, DNA sequences of exon 9 and exon 11 of the c-kit gene were not altered in these tumours. Overall and disease free survival analysis did not reveal any differences between patients with osteosarcoma with c-kit expression and those with c-kit negative tumours.

CONCLUSIONS

C-kit expression is not a prognostic marker in patients with osteosarcoma. The protein expression is not linked to mutations in exon 9 or exon 11 of the c-kit gene. Therefore, these exons may not function as targets for treatment modalities based on the suppression of c-kit tyrosine kinase activity.

High-Resolution 3 T MR Microscopy Imaging of Arterial Walls

PURPOSE

To achieve a high spatial resolution in MR imaging that allows for clear visualization of anatomy and even histology and documentation of plaque morphology in in vitro samples from patients with advanced atherosclerosis. A further objective of our study was to evaluate whether T2-weighted high-resolution MR imaging can provide accurate classification of atherosclerotic plaque according to a modified American Heart Association classification.

METHODS

T2-weighted images of arteries were obtained in 13 in vitro specimens using a 3 T MR unit (Medspec 300 Avance/Bruker, Ettlingen, Germany) combined with a dedicated MR microscopy system. Measurement parameters were: T2-weighted sequences with TR 3.5 sec, TE 15-120 msec; field of view (FOV) 1.4 x 1.4; NEX 8; matrix 192; and slice thickness 600 microm. MR measurements were compared with corresponding histologic sections.

RESULTS

We achieved excellent spatial and contrast resolution in all specimens. We found high agreement between MR images and histology with regard to the morphology and extent of intimal proliferations in all but 2 specimens. We could differentiate fibrous caps and calcifications from lipid plaque components based on differences in signal intensity in order to differentiate hard and soft atheromatous plaques. Hard plaques with predominantly intimal calcifications were found in 7 specimens, and soft plaques with a cholesterol/lipid content in 5 cases. In all specimens, hemorrhage or thrombus formation, and fibrotic and hyalinized tissue could be detected on both MR imaging and histopathology.

CONCLUSION

High-resolution, high-field MR imaging of arterial walls demonstrates the morphologic features, volume, and extent of intimal proliferations with high spatial and contrast resolution in in vitro specimens and can differentiate hard and soft plaques.

Tissue reactions induced by different embolising agents in cerebral arteriovenous malformations: a histopathological follow-up

AIMS

Comparative histopathological analysis was performed in 47 incompletely embolised and resected cerebral arteriovenous malformations (AVMs).

METHODS

Thirty-three AVMs were embolised with n-butyl-cyanoacrylate (NBCA), four with iso-butyl-cyanoacrylate (IBCA), seven with polyvinyl alcohol particles (PVA), one with a fibrin mixture, one with silicon pellets, and one with microcatheter balloons. Maximum exposure time (MET) of the embolising agent (interval between embolisation and surgery) ranged from <24 hours to 80 months. All AVMs were investigated regarding angionecrosis, angiofibrosis, acute inflammation, chronic inflammation, foreign-body reactions, vascular calcification, blood admixture to embolising cast, and capillary recanalisation within the AVMs. These parameters were correlated with MET, comparing different embolising agents, age, and sex.

RESULTS

A typical sequence of events depending on MET is observed in all embolised AVMs: acute inflammation with mural angionecrosis is soon replaced by prominent chronic granulomatous vasculitis, which remains stable and is detectable for a very long time, even in AVMs with a MET of more than 6 years.

CONCLUSION

Capillary recanalisation is always present in incompletely embolised AVMs, detectable after 3 months of MET, irrespective of the embolising agent used. Age and sex does not influence pattern and time course of tissue lesions and recanalisation in incompletely embolised AVMs.

Diagnosis of renal osteodystrophy

The idiom renal osteodystrophy (ROD) represents a heterogeneous pattern of bone disturbances caused by chronic renal insufficiency and concomitant diseases. For the clinical decision of therapy it is most important to differentiate between high and low or adynamic turnover ROD because the therapeutically consequences of these two ends of the ROD spectrum are fundamentally different. Bone histology remains the gold standard for the exact classification of ROD. Serological markers of bone metabolism are not suited for the accurate nomenclature of ROD but are useful for the sequential follow up of ROD after a clear diagnosis has been made. Similarly, radiological diagnosis of ROD using dual energy X-ray absorptiometry (DEXA) or quantitative computer tomography scan (q-CT) is inaccurate and thus more suited for the routine follow up of established disease. Besides mineralization, bone strength and the rate of fractures are strongly determined by the architecture of the bone matrix. This information, however, is also only available on bone biopsy sections and cannot be estimated by non-invasive diagnostic methods. In summary, bone biopsy should be used more liberally for correct classification of bone disease. The sequential follow up and guidance of therapy success can be performed by non-invasive procedures such as biochemical bone marker determination in blood. X-ray imaging and densitometry is suitable only for sequential evaluation of osteoporosis.

Preoperative radiochemotherapy and radical resection for stages II to IV oral and oropharyngeal cancer: grade of regression as crucial prognostic factor

The purpose of this study was to assess the prognostic value of histological response to preoperative radiochemotherapy in an established multimodal therapy concept for advanced oral and oropharyngeal cancer. Two hundred and twenty-two patients who underwent preoperative radiochemotherapy (RCT: 50 Gy, mitomycin C and fluorouracil) and radical surgery were retrospectively evaluated. Resected tumours of all patients were histologically analysed and response to RCT was classified in histopathological grades of regression (RG). In a multivariate statistical analysis, RG was compared with established factors regarding their predictive value for overall and disease-specific survival. The 5-year overall survival probability in the different groups of histopathological regression grades were: RG1 (no vital tumour): 73.4%, RG2 (minimal tumour remnants encompassing less than 5%): 72.1%, RG3 (5-50% vital tumour cells): 41.9%, RG4 (more than 50% vital tumour): 37.9%. For disease-specific survival probability no significant differences were found between both groups of "responders" (RG1 and RG2) nor between "non-responders" (RG3 and RG4), whereas responders and non-responders differed significantly from each other (log-rank test; p < 0.001). T-classification, N-classification and disease stage, histological grading, tumour site, age, and sex had less prognostic value than RG in a Cox regression model. In the neoadjuvant multimodal therapy concept, histological response to preoperative RCT is a crucial prognostic factor even when surgical R0-resection is accomplished. Thus, non-responders have to be regarded as high-risk patients for recurrence and may benefit from further therapy.

Quantification of dose perturbation by plaque in vascular brachytherapy

BACKGROUND

Dose prescription and reporting in vascular brachytherapy (VBT) is based on the assumption that the vessel wall is water equivalent, which does not consider a possible dose perturbation by plaque. As the extent of this perturbation is unknown, we aimed to quantify dose attenuation by atherosclerotic plaque for beta- and gamma-radiation.

MATERIAL AND METHODS

The dose delivered from Strontium-90/Yttrium-90 ((90)Sr/Y) and Iridium-192 ((192)Ir) sources with and without human peripheral arteries ((90)Sr/Y: n = 38, (192)Ir: n = 7) surrounding the respective delivery catheter was determined with radiochromic films. Plaque and vessel wall thickness were measured using light microscopy. From the ratio-attenuated doseunattenuated dose (dose perturbation factor: DPF) we determined averaged attenuation coefficients for atherosclerotic plaque (micro(P)) and the residual part of the vessel wall (micro(W)) by regression analysis based on the function DPF = exp(-micro(P) * plaque thickness -micro(W) * residual wall thickness).

RESULTS

Attenuation in case of (192)Ir was less than the measurement uncertainties. For beta-radiation correlation was found by discrimination between calcified and noncalcified plaque. Classifying noncalcified plaque as normal arterial tissue, the regression coefficient was r = 0.845 at micro(P)= 0.5356 mm(-1) and micro(W) = 0.0663 mm(-1).

CONCLUSIONS

Vascular brachytherapy with beta radiation in calcified arteries results in significant dose attenuation within the vessel wall, which can be calculated on knowing the vascular morphometry. Thus, plaque thickness should be taken into account in treatment planning and retrospective analyses.

Aggressive fibromatosis of the mandible: a case report

An extensive tumour in a 7-year-old girl, leading to severe disfigurement, proved to be an aggressive fibromatosis on histological examination. Eighteen months after surgery there was no evidence of recurrent disease. This suggests that tumour resection and reconstruction of the mandible had been successful. Contrary to some reports, tumour resection led to curative therapy whereas radiotherapy failed.

Conservative treatment of large cystic lesions of the mandible: a prospective study of the effect of decompression

Our aim was to evaluate prospectively the effects of decompression as the primary treatment of large mandibular cysts, irrespective of their histological type. Twenty patients with large mandibular cysts completed treatment successfully. After a mean duration of decompression of 446 days, cysts had shrunk by a mean of 81%. Mean follow-up was 527 days after removal of the decompression stent and removal of the cyst. There were no recurrences. The advantages of this approach are simplicity, immediate gathering of information on the type of cyst with simultaneous start of treatment, low morbidity and low incidence of complications during treatment. Despite the length of the treatment, we recommend the use of decompression stents in the treatment of large mandibular cysts.

Neoadjuvant radiochemotherapy of oral cavity and oropharyngeal cancer: evaluation of tumor response by CT differs from histopathologic response assessment in a significant fraction of patients

BACKGROUND

Our aim was to compare and assess the predictive value of CT and histopathologic grading of tumor regression at primary tumor sites in patients with squamous cell carcinoma of the oral cavity and oropharynx after neoadjuvant (preoperative) radiochemotherapy (RCT).

METHODS

We investigated 55 patients with carcinomas of the oral cavity and oropharynx who underwent RCT before curative surgery. Two blinded observers measured RCT-induced reduction of tumor volume in pretherapeutic and posttherapeutic CT scans. Volume changes were compared with histopathologic findings obtained at surgery.

RESULTS

Histopathologic response evaluation revealed 31 complete remissions, 12 cases of partial response, and 12 nonresponders. We performed a logistic regression analysis to evaluate whether measured volume reduction could predict the likelihood of belonging to a certain response group. Taken together, we found 35 correct, 12 false-negative, and seven false-positive predictions.

CONCLUSIONS

The extent of remission as assessed by CT scans 4 to 5 weeks after completion of neoadjuvant RCT leads to false predictions in a significant percentage of patients.

CD9 expression is not a prognostic factor in human osteosarcoma

CD 9, also known as Motility-Related Protein-1 (MRP-1), is a member of the transmembrane four superfamily and plays a crucial role in cell adhesion, motility and signalling events. Downregulation of CD 9 has been reported to be associated with tumour progression, metastasis and clinical outcome in various kinds of solid tumours. Although prognosis of osteosarcoma has been improved by chemotherapy during the last decades, the problem of non-responders remains. At the present time prognostic factors at diagnosis have not been clearly identified. Furthermore, there is a need for markers that predict the response to chemotherapy at the time of biopsy, allowing stratification of osteosarcoma patients. In this study we investigated the effect of CD9 expression on the response to chemotherapy and survival in osteosarcoma. The expression of CD9 was examined immunohistochemically in 52 patients with high grade osteosarcoma and the results were correlated with histologic response to chemotherapy, 5 year disease free and 5 year overall survival. In patients with osteosarcoma 22 of 52 cases (42%) were positive for CD 9 expression, the rest were negative. CD 9 expression status showed no statistically significant correlation with response to chemotherapy; 41% had a poor response and 59% a good response in the CD9 positive group. In the CD9 negative group 57% had a good and 47% had a bad response. No significant difference was found when comparing disease free survival (58.9% in CD9 positive- versus 69.3% in CD9 negative tumours; P = 0.99) and overall survival of patients (54.0% in CD9 positive- versus 58.1% in CD9 negative tumours; P = 0.90) with CD9 expressing tumours to those with reduced CD9 expression. In conclusion our findings suggest that in contrast to solid tumours, CD9 is unlikely to provide any additional prognostic information for clinical purposes in osteosarcoma patients.

Expression of platelet-derived growth factor-alpha alpha receptor is associated with tumor progression in clear cell renal cell carcinoma

Platelet-derived growth factors (PDGFs) exert their biologic function by binding to 3 different tyrosine kinase receptor isoforms. Especially the PDGF-alpha alpha receptor binds PDGF proteins with high specificity, which results in growth stimulation. The expression of the receptor and its ligand was studied in human renal cell carcinomas (RCCs) by immunohistochemical analysis, and the expression of PDGF-alpha alpha receptor and PDGF-AA was correlated with clinicopathologic parameters of patients with clear cell RCC (CCRCC). In CCRCC, the mean expression of PDGF-alpha alpha receptor and PDGF-AA was 38.8% (range, 0.0%-96.0%) and 18.4% (range, 0.0%-90.0%), respectively. PDGF-alpha alpha receptor expression was significantly higher in grade 3 and grade 4 tumors compared with grade 1 and grade 2 tumors (P = .027; Mann-Whitney test), and high receptor expression correlated with tumor progression in univariate analysis (P = .0253; log-rank test), while PDGF-AA expression had no prognostic influence on the outcome of patients with CCRCC. Therefore, immunohistochemical detection of high PDGF-alpha alpha receptor expression in CCRCC is associated with adverse outcomes. Furthermore, the PDGF receptor-factor interaction loop may be considered as a possible target for novel therapeutic strategies.

Survivin expression in human osteosarcoma is a marker for survival

AIMS

Osteosarcoma is the most frequent malignant bone tumor with a peak incidence in the second and third decade of life. Evaluation of prognosis of patients with osteosarcoma is limited to clinical parameters whereas molecular markers of tumor aggression have not yet been identified. Inhibition of apoptotic cell death could play a role in the development or progression of neoplasia. Survivin is a member of the inhibitor of apoptosis (IAP) protein gene family and is expressed both during normal fetal development and in human cancer.

METHODS

The localization and distribution of survivin was investigated immunohistochemically in high-grade osteosarcomas by an indirect immunoperoxidase method.

RESULTS

Survivin was detected in the cytoplasm in 23/40 and in the nucleus in 20/40 cases of osteosarcoma. Nuclear localization of survivin expression was significantly correlated with a prolonged survival (P=0.0347) but cytoplasmic staining showed no correlation with patient outcome.

CONCLUSIONS

The results of this study indicates that the evaluation of survivin expression might be a useful prognostic marker in osteosarcoma. Patients with osteosarcoma exhibiting nuclear survivin expression could potentially benefit from stratification of neoadjuvant chemotherapy.

Investigation of apparent diffusion constant as an indicator of early degenerative disease in articular cartilage

PURPOSE

To investigate the apparent diffusion constant (ADC) as a prospective magnetic resonance imaging (MRI) marker of early degeneration in articular cartilage.

MATERIALS AND METHODS

Early degenerative changes were studied using in vitro MRI on cartilage-bone specimens excised from human femoral condyles. The loss of proteoglycans developed in vivo due to a degenerative process was compared with a gadolinium diethylenetriamine pentaacetate anion (Gd-DTPA(2-)) enhanced decrease of T(1) relaxation times, and with an increase of ADCs and T(2) relaxation times.

RESULTS

Contrast enhanced T(1) values decreased and the diffusion constants increased in cartilage regions with depleted proteoglycans. The relative changes in diffusion constants were smaller than those of Gd-DTPA(2-) enhanced T(1), and in some proteoglycan-depleted regions no changes in the diffusion constants were detected. T(2) relaxation times showed considerable spatial variability that did not correlate with proteoglycan concentration.

CONCLUSION

In contrast to Gd-DTPA(2-) enhanced T(1), which reflects changes in chemical composition, diffusion constants may reflect structural degradation of the cartilage matrix.

Elective and emergent endovascular treatment of subclavian artery aneurysms and injuries

PURPOSE

To demonstrate our short and long-term results after transbrachial treatment of subclavian artery aneurysms and injuries with stent-grafts in elective and emergency settings.

METHODS

Ten of 12 consecutive patients (6 men; mean age 63.8 years, range 38-80) were treated electively with commercially prepared endografts delivered via a transbrachial access to repair a subclavian artery aneurysm (n=3) or an injury from a misplaced central venous catheter (n=7). Two patients required emergency treatment for a ruptured atherosclerotic aneurysm in one and an unintentional arterial puncture during placement of a central venous access in the other. Stent-graft patency during follow-up was assessed by physical examination with comparison of brachial blood pressures in all patients; computed tomography angiography (CTA) was performed in available patients.

RESULTS

Successful deployment of stent-grafts with sealing of the lesion was achieved in all cases. There were 2 (17%) procedural complications. One patient developed an access-site hematoma that required surgical revision. The second patient, who had a right subclavian injury, suffered an embolic cerebral infarction. The primary stent-graft patency during follow-up (mean 11.6 months) was 100%. CTA examinations in 7 patients at a mean 18 months showed strut dislocation at the thoracic outlet without luminal narrowing in 1 patient. A 50% intraluminal narrowing due to compression between the clavicle and the first rib occurred in another patient. Six patients with a mean follow-up of 23 months (range 0.3-4.5 years) are still alive with patent stent-grafts.

CONCLUSIONS

Endovascular stent-graft treatment of subclavian artery aneurysms and injuries is a less invasive alternative to surgical repair. Long-term results must still be confirmed in further studies.

Expression of platelet-derived growth factor-AA is associated with tumor progression in osteosarcoma

Platelet-derived growth factors are secreted by mesenchymal cells. The homodimer platelet-derived growth factor-AA especially stimulates bone cells through interaction with the platelet-derived growth factor-alpha receptor homodimer. In this study we wanted to determine the expression of the receptor and its ligand in human osteosarcomas and to correlate the expression of platelet-derived growth factor-AA and -alpha receptor with clinicopathological parameters. Fifty-seven osteosarcomas were immunohistochemically analyzed for expression of platelet-derived growth factor-AA and platelet-derived growth factor-alpha receptor. Spearman's correlation coefficient revealed a strong correlation between the expression of platelet-derived growth factor-AA and platelet-derived growth factor-alpha receptor (r = 0.867). No differences were observed relative to gender, age, tumor stage, tumor location, and response to neoadjuvant chemotherapy between high or low platelet-derived growth factor-AA and platelet-derived growth factor-alpha receptor expression. High platelet-derived growth factor-AA expression correlated with tumor progression in univariate analysis (P = .0415; log-rank test), whereas platelet-derived growth factor-alpha receptor expression showed a trend toward a shorter disease-free survival, which failed to reach significance (P = .0627, log-rank test). In multivariate analysis, platelet-derived growth factor-AA expression remained a significant independent predictor of tumor progression (P = .021, Cox regression). Immunohistochemical analysis of platelet-derived growth factor-AA expression in osteosarcoma may be a useful marker of prognosis and may be considered as a possible target for novel therapeutic strategies.

MRI of the cartilage

With the introduction of fat-suppressed gradient-echo and fast spin-echo (FSE) sequences in clinical routine MR visualization of the hyaline articular cartilage is routinely possible in the larger joints. While 3D gradient-echo with fat suppression allows exact depiction of the thickness and surface of cartilage, FSE outlines the normal and abnormal internal structures of the hyaline cartilage; therefore, both sequences seem to be necessary in a standard MRI protocol for cartilage visualization. In diagnostically ambiguous cases, in which important therapeutic decisions are required, direct MR arthrography is the established imaging standard as an add-on procedure. Despite the social impact and prevalence, until recent years there was a paucity of knowledge about the pathogenesis of cartilage damage. With the introduction of high-resolution MRI with powerful surface coils and fat-suppression techniques, visualization of the articular cartilage is now routinely possible in many joints. After a short summary of the anatomy and physiology of the hyaline cartilage, the different MR imaging methods are discussed and recommended standards are suggested.

Expression of osteopontin and vascular endothelial growth factor in benign and malignant bone tumors

Osteopontin (OPN), one of the major non-collagenous proteins of bone matrix, is together with vascular endothelial growth factor (VEGF) a potent angiogenic protein. In this study we determined the expression of OPN in benign and malignant bone tumors and investigated the prognostic influence of OPN expression on the outcome of osteosarcoma patients. Fifty-seven osteosarcomas and 11 osteoblastomas as well as 5 bone specimens with remodeling sites were immunohistochemically analyzed for expression of OPN and VEGF. OPN was not detected in osteoblasts of remodeling sites. Osteoblastoma osteoblasts as well as osteoclastlike giant cells and osteosarcoma mononuclear cells showed variable staining. In osteosarcomas OPN and VEGF expression correlated with each other (r=0.390, P=0.003, Spearman's test). Although osteosarcoma patients with high VEGF expression showed a trend towards shorter overall survival ( P=0.0841, log-rank test), OPN expression had no influence on patients overall or on disease-free survival. Our data indicate that expression of this protein might be upregulated in bone neoplasia. Although OPN expression correlates with VEGF expression in osteosarcomas, OPN expression does not provide predictive information about the outcome of osteosarcoma patients.

[Coxarthrosis]

Osteoarthritis of the hip joint is a very common disease. There is a minor prevalence of males. By etiology one can distinguish primary (idiopathic) from secondary osteoarthritis. Secondary are due to well-known etiologies as overweight, repetitive traumata, malposture, muscle- and tendon-imbalance etc. Osteoarthritis includes not only cartilage abnormalities, but also such of the subchondral-region, synovialis, synovial fluid and periarticular muscles. The cartilage shows in osteoarthritis typically edema and swelling, defects with tears, fibrillation, and "baldness" and (or) cartilagenous repair-islands and joint space narrowing as well, while subchondrally micro-edema, necrosis, ev. microfractures, "cysts", demineralisation followed by sclerosis, osteophyte-formation and deformity is seen. With conventional radiographs and CT joint space narrowing, subchondral cysts, sclerosis and osteophytes and deformities are well delineated, MRI however allows visualization of subtle bone marrow and cartilage abnormalities. Clinically, the diagnosis of pre-osteoarthritis becomes more and more important. This includes e.g. deformities and malpostures, labrum-pathologies and structural imbalances. There are three prognostic different types of hip-osteoarthritis depending on the migration of the head of the hip joint: the most common are the latero-cranial and the medio-caudal ones, while the central one is found very rarely. Basic imaging method are conventional radiographs, and CT, followed by MRI. The diagnosis of an "activated osteoarthritis" is made by bone-scintigraphy or MRI with i.v. application of contrast-media. The labrum- and cartilage diagnosis should be done with MRI or MR-arthrography. Functional computer-animated analysis will be of great diagnostic value in the near future. MRI indications are differences between clinical results and imaging, missing clinical improvement of an "activated" osteoarthritis under standard therapy, unclear joint-pain and before any arthroscopy.

Pathophysiology and imaging in inflammatory and blastomatous synovial diseases

Variable pathologies are subsumed under the term "synovial disease", including common pathologies such as rheumatoid arthritis. While formerly radiologists had to rely on conventional radiographs and bone scintigraphy with their inherent problems in visualizing soft tissue, noninvasive imaging of the synovium has recently improved substantially with the technical development of MRI and (Doppler) ultrasound. These imaging modalities allow differentiation of characteristic pathologic features based on a profound knowledge of normal anatomy and pathophysiology.