What Factors Are Associated With Stem Breakage in Distal Femoral Endoprosthetic Replacements Undertaken for Primary Bone Tumors?

BACKGROUND

The advantages of distal femoral replacement prostheses for reconstructions after tumors are well known; one such implant, the Global Modular Replacement System (GMRS), has been widely used since 2003. Although implant breakage has been reported, the frequency of this event has varied across different studies.

QUESTIONS/PURPOSES

(1) What percentage of patients who underwent distal femur resection and replacement using the GMRS for primary bone tumors at one center experienced stem breakage? (2) At what timepoints did these breakages occur, and what factors were common among the stems that broke?

METHODS

We performed a retrospective study of all patients who underwent distal femur resection and replacement using the GMRS for a diagnosis of primary bone sarcoma by the Queensland Bone and Soft-tissue Tumor service from 2003 to 2020 who had a minimum of 2 years of follow-up. Standard follow-up for primary bone sarcoma involves radiographic imaging of the femur at 6 weeks and 3 months postoperatively and yearly thereafter. From a chart review, we identified patients with femoral stem breakage. Patient and implant details were recorded and analyzed. A total of 116 patients had undergone a distal femoral replacement with the GMRS prosthesis for primary bone sarcoma; however, 6.9% (eight of 116 patients) died before completing the 2-year follow-up period and were excluded. Of the remaining 108 patients, 15% (16 patients) had died at the time of this review; however, given that they completed the 2-year follow-up period and did not experience stem breakage, they were included. Furthermore, 15% (16 patients) were considered lost to follow-up and excluded because they have not been seen in the past 5 years but were not known to have died or experienced stem breakage. This left 92 patients for analysis.

RESULTS

Stem breakages were identified in 5.4% (five of 92) of patients. All stem breakages occurred in stem diameters 11 mm or less with a porous body construct; the percentage of patients with breakage in this group was 16% (five of 31). All patients with stem fracture demonstrated minimal ongrowth to the porous coated body. The median time to stem fracture was 10 years (range 2 to 12 years); however, two of the five stems broke within 3 years.

CONCLUSION

We recommend the use of a larger-diameter GMRS cemented stem (> 11 mm), and either the line-to-line cementing method or an uncemented stem from an alternative company should be considered in order to achieve this larger stem in smaller canals. If a stem less than 12 mm in diameter must be used or there is evidence of minimal ongrowth, then close follow-up and prompt investigation of new symptoms should occur.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Femoral bone growth after extendible endoprosthetic replacement of the proximal tibia in skeletally immature patients

There is increasing preference for limb salvage techniques in the management of pediatric musculo- skeletal tumors. This study was aimed at evaluating femoral growth following proximal tibia resection (PTR) and placement of an extendible endoprosthesis with sliding stem. This was a retrospective study. The demographic and clinical data were collected. All the patients with malignant tumors were fully staged and commenced on appropriate chemotherapy. An expected discrepancy of > 3cm was considered substantial enough to warrant extendible prosthesis. Twelve patients who had follow up full length scanogram of the lower limbs were included for the evaluation of femoral growth. The last available scanograms were used for growth comparison of the femur. The age at resection for all twelve patients ranged from 4-13 years. The commonest histological diagnosis was Osteosarcoma. In the twelve patients assessed for the growth of femur, the mean femoral length was 96% [89%-102%] of the unaffected femur. Distal femoral physeal growth continued after implantation of a sliding extendible prosthesis after resection of proximal tibia tumors.

Popliteal artery entrapment syndrome secondary to a femoral osteochondroma

BACKGROUND

Osteochondromas (or exostoses) are the most common benign tumors of the bone. Vascular complications of these tumors are rare but have been increasingly reported in recent literature.

AIM

Throughout an unusual case report of popliteal artery entrapment syndrome secondary to a femoral osteochondroma, we highlight the necessity of thorough clinical and radiological examinations as well as meticulous and prompt surgical resection.

CASE REPORT

A 27-year-old male patient, who had been diagnosed with multiple osteochondromas and had never been operated on, presented with a one-year history of exercise-induced left calf pain, paresthesias of the left leg and pallor in cold weather. After radiographic and Computed Tomography angiographic evaluation, we diagnosed distal femur osteochondroma associated with an arterial compression of the left popliteal artery. A surgical treatment of all lesions was performed. No operative complications occurred. The pain was relieved. Good postoperative results have been noticed.

CONCLUSION

Popliteal aretery entrapment syndrome may be caused by solitary or multiple osteochondromas around the knee. Therefore, prophylactic resection of exostoses in the surrounding area of a vessel should be performed. Moreover, the orthopedic surgeon should consider and prevent vascular complications during surgical resection of knee osteochondromas.

Very late relapse of high-grade osteosarcoma: A case report and review of the literature

RATIONALE

Osteosarcoma is the most common primary malignant bone tumor in children. The prognosis of osteosarcoma has improved with the use of aggressive systemic chemotherapy in addition to surgery. The relapse of osteosarcomas is usually as lung metastasis observed within 2 to 3 years after the initial treatment. A relapse is rarely observed at >10 years.

PATIENT CONCERNS

We report the case of a 51-year-old Japanese man who was treated for high-grade osteosarcoma of the femur at 13 years old. He was referred to our hospital with a suspicion of primary lung cancer based on back pain, respiratory distress, and an abnormal mass on chest radiograph.

DIAGNOSES

Computed tomography-guided biopsy confirmed the lung lesion as a metastatic recurrence of high-grade osteosarcoma without local recurrence.

INTERVENTIONS

Chemotherapy was planned, but the patient's general condition rapidly deteriorated and thus palliative therapy was provided.

OUTCOMES

The patient died 2 months after the initial consultation.

LESSONS

The survival durations of osteosarcoma patients have been prolonged by recent progress in multimodality therapy, and thus clinicians as well as osteosarcoma patients should always keep in mind the possibility of very late relapse.

Unusual Bone Lesions with Osteonecrosis Mimicking Bone Metastasis of Squamous Cell Carcinoma in Recessive Dystrophic Epidermolysis Bullosa

Some bone lesions are reported to mimic bone metastasis on imaging tests. Herein, we report a case of a 55-year-old Japanese man who presented with a skin tumor on the left lower extremity. He also had a history of recurrent generalized cutaneous blister and erosion formation since childhood. His skin lesions were diagnosed as cutaneous squamous cell carcinoma complicated by recessive dystrophic epidermolysis bullosa. Magnetic resonance imaging of the left lower extremity detected multiple focal bone lesions mimicking bone metastases in the left femur and tibia. However, bone biopsy revealed that the bone lesions were osteonecrosis without tumor cells. We suggest that cancer-induced osteonecrosis should be included in the differential diagnosis of bone lesions suspected of being metastases on magnetic resonance imaging.

Desmoplastic fibroma of the femur with atypical image findings: A case report

RATIONALE

Desmoplastic fibroma of the bone (DFB) is an extremely rare benign bone tumor, which can occur in any bone at all ages. Herein, we report a case of non-specific imaging findings.

PATIENT CONCERNS

A 25-year-old female patient was consulted in the Armed Police General Hospital (Beijing, China) due to repeated pain in the right thigh lasting over 1 year. Imaging examination revealed a space-occupying lesion in the right femur.

DIAGNOSIS

Desmoplastic fibroma of the femur INTERVENTIONS:: Wide surgical resection OUTCOMES:: At the 1-year follow-up visit, no relapse in the tumor was observed.

LESSONS

In this case report, we described and emphasized the particularity of the case examined and the possible non-specificity of the imaging results of some DFB cases.

Adult Langerhans' cell histiocytosis with multisystem involvement: A case report

RATIONALE

Langerhans' cell histiocytosis (LCH), also called histiocytosis X, is an uncommon disorder manifesting in a variety of ways. Although LCH can involve various organs including bone, skin, and lymph nodes, multisystem involvement of LCH is rare in adults.

PATIENT CONCERNS

A 31-year-old woman first presented to our hospital with left leg pain. She had a history of a 20-kg weight gain over three months.

DIAGNOSES

X-ray, magnetic resonance imaging (MRI), computed tomography (CT), and bone scan images revealed enhancing lesions in the left femur and right temporal bone, multiple cystic lesions in the lung, enhancing mass in the pituitary stalk, and fat density lesions in the liver. The patient underwent excisional biopsy for the femoral lesion and histologic examination confirmed the diagnosis of LCH.

INTERVENTIONS

Excisional biopsy was performed for the bony lesion in the left femur. She received chemotherapy with vinblastine and prednisolone.

OUTCOMES

The patient expired after 21 months from initial admission following recurrent episodes of pneumothorax, pneumonia, and sepsis.

LESSONS

Our case showed LCH involvement in bone, lung, central nervous system (CNS), and liver. Although it is occasionally difficult to discriminate LCH from other disorders, systemic evaluation might be helpful for differential diagnosis. Familiarity with the various multisystemic involvements of LCH on imaging is vital for diagnosing and managing patients in daily practice.

Giant periosteal aggressive epithelioid osteoblastoma: 21-year-old male presents case in the midshaft of his femur

We report a rare case of giant periosteal osteoblastoma in the femur of a 21-year-old male. The patient presented with a painful, firm, non-tender mass in his left thigh. The pain was worse at night and was temporarily relieved with NSAIDS. He had no fevers, night sweats, or weight loss. The patient underwent preoperative radiological studies including plain radiographs, MRI, bone scan, and CT scan. An open biopsy was subsequently performed that was consistent with an aggressive, epithelioid osteoblastoma. Pathology demonstrated a neoplasm characterized by cohesive sheets of epithelioid osteoblasts, mixed with areas of conventional osteoblastoma displaying prominent osteoblastic rimming of woven bone trabeculae in a fibrovascular stroma. The patient subsequently underwent resection, cryosurgery, fixation, and bone grafting with cortical strut allografts. At final follow-up, 32 months postoperatively, there was no evidence of local recurrence. The patient had resumed all his normal activities. He could run without pain and had no restrictions with activities. The goal of this case report is to aid professionals in the diagnosis and treatment of highly uncommon aggressive osteoblastomas.

MRI assessment of the bone adjacent to giant cell tumours and its association with local recurrence after intralesional curettage

AIM

To assess the tumour border surrounding giant cell tumour of the bone (GCTB) using magnetic resonance imaging (MRI) and investigate its association with local recurrence.

MATERIALS AND METHODS

Sixty-nine GCTBs in proximal tibiae and distal femurs were studied. The pathological basis of the paintbrush border sign was explored. Expression of Ki-67, matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF), receptor activator of nuclear factor-κ B (RANK), and RANK ligand (RANKL) in GCTBs were investigated using immunohistochemistry. Patients treated with intralesional curettage were analysed retrospectively to investigate the prognostic role of the paintbrush border sign. The differences between rates were tested using the chi-square test or Fisher's exact test, as appropriate.

RESULTS

The paintbrush border sign correlated well with infiltrative margins. The expression of MMP-9 was associated with the paintbrush border sign, and positively correlated with RANKL and VEGF expression. GCTBs with the paintbrush border sign had a higher rate of local recurrence (76.19 versus 20.59%, p<0.05). The paintbrush border sign was more common in proximal tibiae, and positively correlated with cystic change. The paintbrush border signs were detected at T1-weighted imaging, but the sign was only evident in four cases on T2-weighted imaging.

CONCLUSION

Pathologically, the paintbrush border sign correlates well with invasion of the bone around GCTB. MMP-9 might play a key role in the formation of penetrating irregular margins. The paintbrush border sign is revealed as a risk factor for local recurrence of GCTB. Sagittal T1-weighted imaging is crucial to diagnose the paintbrush border sign.

A case of enchondroma from Carolingian necropolis of St. Pere De Terrassa (Spain): An insight into the archaeological record

Enchondromas occur with an estimated modern incidence rate of 27.7% of benign bone tumors (Hauben and Hogendoorn, 2010), but few are represented in the paleopathological record. The medieval site of St. Pere in Spain has produced a convincing case. The diagnosis was confirmed by X-Ray, CT-scan and μ-CT scan. Therefore UF 755 from St. Pere - a male of more than 60 years old - can be confirmed as a femoral case of enchondroma, supported by evidence, in the paleopathological record.

MRI Identification of the Osseous Extent of Pediatric Bone Sarcomas

BACKGROUND

The quantitative accuracy of MRI in predicting the intraosseous extent of primary sarcoma of bone has not been definitively confirmed, although MRI is widely accepted as an accurate tool to plan limb salvage resections. Because inaccuracies in MRI determination of tumor extent could affect the ability of a tumor surgeon to achieve negative margins and avoid local recurrence, we thought it important to assess the accuracy of MR-determined tumor extent to the actual extent observed pathologically from resected specimens in pediatric patients treated for primary sarcomas of bone.

QUESTIONS/PURPOSES

(1) Does the quantitative pathologic bony margin correlate with that measured on preoperative MRI? (2) Are T1- or T2-weighted MRIs most accurate in determining a margin? (3) Is there a difference in predicting tumor extent between MRI obtained before or after neoadjuvant chemotherapy and which is most accurate?

METHODS

We retrospectively studied a population of 211 potentially eligible patients who were treated with limb salvage surgery between August 1999 and July 2015 by a single surgeon at a single institution for primary sarcoma of bone. Of 131 patients (62%) with disease involving the femur or tibia, 107 (51%) were classified with Ewing's sarcoma or osteosarcoma. Records were available for review in our online database for 79 eligible patients (37%). Twenty-six patients (12%) were excluded because of insufficient or unavailable clinical or pathology data and 17 patients (8%) were excluded as a result of inadequate or incomplete MR imaging, leaving 55 eligible participants (26%) in the final cohort. The length of the resected specimen was superimposed on preresection MRI sequences to compare the margin measured by MRI with the margin measured by histopathology. Arithmetic mean differences and Pearson r correlations were used to assess quantitative accuracy (size of the margin).

RESULTS

All MR imaging types were positively associated with final histopathologic margin. T1-weighted MRI after neoadjuvant chemotherapy and final histopathologic margin had the strongest positive correlation of all MR imaging and time point comparisons (r = 0.846, p < 0.001). Mean differences existed between the normal marrow margin on T1-weighted MRI before neoadjuvant chemotherapy (t = 8.363; mean, 18.883 mm; 95% confidence interval [CI], 14.327-23.441; p < 0.001), T2-weighted MRI before neoadjuvant chemotherapy (t = 8.194; mean, 17.204 mm; 95% CI, 12.970-21.439; p < 0.001), T1-weighted after neoadjuvant chemotherapy (t = 10.808; mean, 22.178 mm; 95% CI, 18.042-26.313; p < 0.001), T2-weighted after neoadjuvant chemotherapy (t = 10.702; mean, 20.778 mm; 95% CI, 16.865-24.691; p < 0.001), and the final histopathologic margin. T1-weighted MRI after neoadjuvant chemotherapy compared with the final histopathologic margin had the smallest mean difference in MRI-measured versus histopathologic margin size (mean, 5.9 mm; SD = 4.5 mm).

CONCLUSIONS

T1 MRI after neoadjuvant chemotherapy exhibited the strongest positive correlation and smallest mean difference compared with histopathologic margin. When planning surgical resections based on MRI obtained after neoadjuvant chemotherapy, for safety, one should account for a potential difference between the apparent margin of a tumor on an MRI and the actual pathologic margin of that tumor of up to 1 cm.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Synovium as a widespread pathway to the adjacent joint in undifferentiated high-grade pleomorphic sarcoma of the tibia: A case report

RATIONALE

Undifferentiated high-grade pleomorphic sarcoma (UPS), originated from bone, is a rare tumor, accounting for 2% to 5% of all primary maligment bone neoplasms. Skip lesion can be found in undifferentiated high-grade pleomorphic sarcoma of bone (UPS-B). However, the direct invasion across the articular synovium to bone has not been reported previously.

PATIENT CONCERNS

We report an unusual case of a 65-year-old man complained of a year history of pain, swelling, and limitation of activity in the left knee joint. At the proximal tibia, there was extensive invasion of articular synovium, which provides a direct anatomic pathway for the tumor invasion to the adjacent bone, including patella and femoral condyle.

DIAGNOSES

Magnetic resonance imaging was important in defining the marrow involvement and joint invasion, including the thickening articular synovium. Subsequent pathological examination confirmed the diagnosis of UPS.

INTERVENTIONS

The patient underwent an extensive resection of the knee joint, except for the patellar.

OUTCOMES

After operation, routine chemotherapy was performed. Unfortunately, half a year later, soft tissue swelling of whole thigh was found. Then this patient came our hospital again. Positron emission tomography imaging showed there was recurrence of UPS with lung metastasis. A week later, this patient died.

LESSONS

In contrast to frequent infiltration pathway, the articular synovium as a media for this tumor spread is rare. This study adds a better understanding of this direct invasion way to the medical literature.

Fracture after radiation therapy for femoral metastasis: incidence, timing and clinical features

We analyzed 428 femoral metastases initially treated with radiotherapy between 2002 and 2011 to clarify the clinical details of post-irradiation fractures of femoral metastasis. Patients included 161 men and 167 women, with a mean age of 62 years. Fracture incidence, fracture site, fracture risk based on X-ray images before radiotherapy, and interval from completion of radiotherapy to fracture occurrence were assessed. In addition, 24 pathological specimens obtained during 27 surgeries for these fractures were examined. Fractures occurred in 7.7% of 428 femoral metastases (total 33: 28 actual fractures and five virtual fractures with progressive pain and bone destruction). The fracture rate was 7.8% in the proximal femur and 1.5% in the shaft (P = 0.001). Fractures occurred a median of 4.4 months after radiotherapy, with 39.4% occurring within 3 months and 63.6% within 6 months. Among femurs with high fracture risk according to Harrington's criteria or Mirels' score, the fracture rate was 13.9% and 11.8%, respectively. Viable tumor cells were detected in all five patients with painful virtual fracture, in 85.7% of femurs with actual fractures that occurred within 3 months, and in only 25.0% of actual fractures occurring after 3 months. Post-irradiation fractures of femoral metastasis most frequently occurred within 3 months after radiotherapy, and were more common in the peritrochanteric area than in the shaft. Radiological evidence of impending fracture did not correlate with a high fracture rate. Actual fractures occurring after more than 3 months were likely caused by post-irradiation fragility of the femur, without viable tumor cells.

What Happens to the Articular Surface After Curettage for Epiphyseal Chondroblastoma? A Report on Functional Results, Arthritis, and Arthroplasty

BACKGROUND

Chondroblastoma is an uncommon, benign, but locally aggressive bone tumor that occurs in the apophyses or epiphyses of long bones, primarily in young patients. Although some are treated with large resections, aggressive curettage and bone grafting are more commonly performed to preserve the involved joint. Such intralesional resection may result in damage to the growth plate and articular cartilage, which can result in painful arthritis. Prior studies have focused primarily on oncologic outcomes rather than long-term joint status and functional outcomes.

QUESTIONS/PURPOSES

(1) What local complications can be expected after aggressive intralesional curettage of epiphyseal chondroblastoma? (2) What is the joint survival of a joint treated in this way for chondroblastoma? (3) What additional procedures are used in treating symptomatic joint osteoarthritis after treatment of the chondroblastoma? (4) What are the functional outcomes in this group of patients?

METHODS

A retrospective study of our prospectively collected database between 1975 and 2013 was done. We found 64 patients with a diagnosis of chondroblastoma of bone. After applying our selection criteria, 53 patients were involved in this study. We excluded seven patients with tumors initially treated with en bloc resection (five located in the extremities and two in the axial skeleton) and two patients with apophyseal tumors. One patient who underwent nonsurgical treatment and one patient lost to followup were also excluded. The mean age was 18 years (range, 11-39 years); the minimum followup was 2 years with a mean followup 77 months (range, 24-213 months). We analyzed all patients with a diagnosis of epiphyseal chondroblastoma of the limb treated with aggressive curettage and joint preservation surgery. During the period in question, our general indications for curettage were patients with active, painful tumors and those with more aggressive ones that remained intracompartmental, whereas initial wide en bloc resection was indicated in patients who had tumors with an extracompartmental extension breaching the adjacent joint cartilage and massive articular destruction. The tumor location was the distal femur in 14 patients, proximal tibia in 11, proximal humerus in 10, proximal femur in eight, the talus in seven, and elsewhere in the lower extremity in three. Local complications including joint degeneration and tumor recurrence were evaluated. Based on radiographic analysis, secondary osteoarthritis was classified by using the Kellgren-Lawrence grading system from Grade 0 to Grade IV. Patients who underwent joint replacement resulting from advanced symptomatic osteoarthritis were considered to have had joint failure for purposes of survivorship analysis, which was estimated using the Kaplan-Meier method. Functional results were evaluated with the Musculoskeletal Tumor Society functional score by the treating surgeon, who transcribed the results on the digital records every 6 months of followup.

RESULTS

Twenty-two patients (42%) developed 26 local complications. The most common local complication was osteoarthritis in 20 patients (77% [20 of 26 complications]); tumor recurrence was observed in four patients; an intraarticular fracture and superficial infection treated with surgical débridement and antibiotics developed in one patient each. Joint survival was 90% at 5 years (95% confidence interval [CI], 76%-100%) and 74% at 10 years (95% CI, 48%-100%). Proximal femoral tumor location was associated with lower survivorship of the joint than other locations showing a 5-year survival rate of 44% (95% CI, 0%-88%; p = 0.000). Of the 20 patients with osteoarthritis, four were symptomatic enough to undergo joint replacement, all of which were for tumors in the proximal femur. The mean Musculoskeletal Tumor Society functional score was 28 of 30 points (93%).

CONCLUSIONS

Osteoarthritis was a frequent complication of aggressive curettage of epiphyseal chondroblastoma, and tumors located in the proximal femur appeared to be at particular risk of secondary osteoarthritis and prosthetic replacement. Because chondroblastoma is a tumor that disproportionately affects younger patients, the patient and surgeon should be aware that arthroplasty at a young age is a potential outcome for treatment of proximal femoral chondroblastomas.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Intra-articular osteoid osteoma at the femoral trochlea treated with osteochondral autograft transplantation

We present the case of an intra-articular osteoid osteoma at the femoral trochlea. Intra-articular osteoid osteoma can present a diagnostic challenge both clinically and with imaging because it presents differently from the classic cortical osteoid osteoma. Given the lesion's proximity to overlying cartilage, the patient underwent resection of the lesion with osteochondral autograft transplantation at the surgical defect. A comprehensive literature review and discussion of intra-articular osteoma will be provided.

Trauma-Induced Resolution of Solitary Osteochondroma of the Distal Femur

Osteochondromas are benign lesions manifested as bony protrusions capped by cartilage. The exact cause of these growths is not known, and there is no treatment other than surgical excision if the lesion becomes symptomatic. Spontaneous resolution is an uncommon phenomenon that is not completely understood. A 12-year-old girl presented with a mass behind the left knee diagnosed as an osteochondroma. She was followed with serial radiographs because the lesion was minimally symptomatic. At 2.5 years after presentation, the patient reported feeling a "pop" with knee hyperflexion, and radiographic follow-up confirmed a decrease in the size of the growth. The protrusion continued to decrease in size until it was no longer detectable with radiographs, physical examination, and advanced imaging. Spontaneously resolving osteochondromas have been previously documented, but the literature is limited. There were just over 20 cases reported as of the writing of this article, and only 1 other case includes postresolution magnetic resonance imaging. This report of localized trauma inducing spontaneous resolution provides additional evidence and insight supporting previous theories on spontaneous resolution of osteochondromas, which may assist in counseling patients and their families regarding expected natural history. [Orthopedics.2016; 39(5):e1001-e1004.].

Linea Aspera as Rotational Landmark for Tumor Endopostheses: A Computed Tomography Study

This computed tomography study examined the reliability of the linea aspera as a rotational landmark in tumor endoprosthetic replacement by determining its cross-sectional location on the femur.

Malignant Transformation of an Aneurysmal Bone Cyst to Fibroblastic Osteosarcoma

Aneurysmal bone cysts are uncommon primary bone tumors typically regarded as histologically and clinically benign. Malignant transformation of these lesions occurs almost exclusively in the context of prior radiation exposure. However, 4 cases of an osteosarcoma developing without prior radiation exposure have been reported. In this article, we report a fifth case of degeneration of an aneurysmal bone cyst to a fibroblastic osteosarcoma. In addition to reviewing the earlier cases, we describe the radiologic, pathologic, and immunohistochemical basis of this diagnosis.

Solitary Osteochondroma in a Ring-Tailed Lemur (Lemur catta)

A 20-y-old, male, ring-tailed lemur (Lemur catta) presented with a large, firm mass on the proximal caudolateral left femur. The animal displayed no clinical signs associated with the mass. Radiographs revealed a mineralized mass protruding from the femur, with an intact femoral cortex. Histopathology diagnosed osteochondroma in view of the presence of a peripheral layer of cartilage with progressive endochondral ossification and typical remodeling of bony trabeculae. The mass grew quickly after the initial biopsy, and a second surgery to debulk 95% of the tumor was performed. Histopathologic features of the larger samples were similar to those of the initial biopsies, with the cartilage layer being discontinuous and development of bone from some borders progressing directly from a periost-like layer. Nineteen months after the second surgery, the mass had regrown and extended further proximally on the femur toward the epiphysis, but the animal remained asymptomatic, and additional debulking was not attempted. This report is the first description of an osteochondroma in a prosimian and describes unique behavior of the tumor compared with osteochondromas found in humans, dogs, and cats.

Intermittent internal fixation with a locking plate to preserve epiphyseal growth function during limb-salvage surgery in a child with osteosarcoma of the distal femur: a case report

Limb shortening is a problem associated with surgery for osteosarcoma of the lower extremity in adolescents, as the tumors frequently occur near the epiphysis. Herein we report the use of a less invasive stabilization system (LISS) and an intermittent fixation method to preserve the growth function of epiphysis in an 11-year-old patient with an osteosarcoma of the distal femur.The 11-year-old male presented with left knee enlargement and pain for 2 weeks, and magnetic resonance imaging (MRI) and biopsy were consistent with osteosarcoma of the left distal femur. After preoperative chemotherapy, en bloc tumor resection was performed with margins based on MRI findings preserving the epiphyseal growth plate, the tumor cavity was filled with inactivated bone and bone cement, and a LISS was used to stabilize the femur. Aggressive postoperative chemotherapy was given. Approximately 105 weeks after surgery radiography showed that the distal end of the plate had moved superior to the epiphysis along with bone growth. Locking screws were placed in the distal part of the LISS plate to stabilize the re-implanted bone, and external fixation was not needed.The patient was able to walk with the crutches 1 week postoperatively, and bear weight on the extremity 6 weeks postoperatively. At 6 years after surgery, the patient's height had increased 52 cm, shortening of the affected limb was only 1 cm, and the circumference of the affected limb was 2 cm smaller than that of the contralateral limb. There was no significant discomfort in the affected limb, and there was no gait abnormality. The patient could jump and run, and could participate in sports including basketball and badminton to the same degree as his peers.In summary, the novel method of bone reconstruction and fixation provided good results in a child with an osteosarcoma of the distal femur. This fixation method preserves the osteogenic function of the epiphysis and restored bone integrity simultaneously, and provides good functional recovery.

Composite artificial semi-knee joint system

OBJECTIVES

The purpose of the study was to investigate the clinical implantation protocol of custom-made artificial semi-knee joint based on computer-aided design so as to improve the limb salvage efficiency.

MATERIALS AND METHODS

The custom-made artificial semi-knee joint was designed and manufactured based on rapid prototyping technology. The repeated modifications were carried out in the design and manufacture of the semi-knee joint, together with the operation protocol. Clinical trial was conducted on 2 cases of osteosarcoma, one receiving allograft prosthesis composite transplantation, and the other receiving synthetic bone graft prosthesis composite transplantation. The clinical outcomes of the 2 patients were evaluated.

RESULTS

The custom-made artificial semi-knee joint met the clinical customization needs. In clinical trial, 18-month follow-up demonstrated the satisfactory knee joint function recovery in near future.

CONCLUSIONS

The custom-made artificial semi-knee joint based on computer-aided design can afford satisfactory knee joint function recovery following allograft bone transplantation.

Patient-specific imaging and missed tumors: a catastrophic outcome

Patient-specific instrumentation (PSI) is a relatively new technology aimed at increasing the accuracy and efficiency of total knee arthroplasty (TKA). Its premise is reliant upon preoperative imaging techniques to acquire detailed measurements of a patient's distal femur and proximal tibia. Although a limited number of studies in the current literature have begun to critically evaluate this promising technology, a number of potential controversies exist. We present 2 patients with radiographic evidence of musculoskeletal neoplasms present on initial preoperative imaging that were not recognized prior to placement of patient-specific total knees. The expanding role of non-diagnostic imaging in TKA is examined, and we suggest guidelines for prevention of further devastating outcomes.

Asymptomatic grade-2 central chondrosarcoma of the distal femur with non-aggressive radiological features

This paper discusses the case of a 57-year-old man with an incidental finding of a radiologically non-aggressive chondroid lesion and concomitant osteonecrosis in the left distal femur. The final resected specimen showed a grade-2 chondrosarcoma. This case illustrates that long-term follow-up is necessary for non-aggressive chondroid lesions. If surgical management is considered, resection with an adequate margin is superior to intralesional curettage.

Treatment of bone tumors in the femoral trochanteric area

OBJECTIVE

To report the management of bone tumor in the femoral trochanteric area in terms of safety,functional outcome and patient satisfaction.

MATERIAL AND METHOD

Thirty-eight patients with impending or pathological fracture at the trochanteric region of the femur were treated surgically at the Department of Orthopaedic Surgery, Faculty of Medicine Siriraj Hospital from 1998 to 2007. Thirteen males and 25 females with a mean age of 49.7 years, 11 patients had benign bone tumors (5 fibrous dysplasia, 3 chondroblastoma and 1 each of aneurysmal bone cyst, bone island and intraosseous hemangioma). Twenty-seven patients had metastatic lesions (10 breast, 3 lung, 2 hepatocellular, 2 colon, 2 prostate and 1 each of multiple myeloma, gastric, cervix, thyroid, nasopharynx, bladder, secondary sarcoma and of unknown origin). Twenty-six patients presented an impending fracture and the remainder had a pathological fracture. All patients were treated with curettage in conjunction with a sliding hip compression screw and plate, except one patient with bone deformity from fibrous dysplasia who had an adjunct valgus osteotomy. Eleven patients were augmented with bone grafting, 19 with bone cement and 8 patients had no augmentation.

RESULTS

The mean follow-up time was 3 years. The mean operative time and estimated blood loss was 98 minutes and 542 ml respectively. Two complications were found in this series and successfully managed. There was no serious intra or perioperative complication. The mean functional score was 79.5 percent in metastatic group and 89.7 percent in benign bone group.

CONCLUSION

In the present study, the outcomes of intralesional curettage and stabilization with a sliding hip compression screw and plate for bone tumors in the femoral trachanteric area were safe and only 2 treatable complications were found. Most patients had less pain after the operation and could ambulate independently with gait support and all satisfied with the results.

Chondroblastoma of the femoral head disrupting the articular cartilage. Description of a novel surgical technique

Chondroblastoma is a rare benign tumour. Involvement of the femoral head may often lead to a delayed diagnosis. We present the case of a 15-year-old patient with right hip pain which was first attributed to adductor tendinitis. Following aggravation of the symptoms, thorough investigation including a CT-guided biopsy, revealed the diagnosis of chondroblastoma of the femoral head. Removal of the lesion based on the techniques described in literature was not possible, mainly because the articular cartilage was breached. A novel surgical technique was used in order to address the rare location and behaviour of the tumour. This technique offered the patient pain relief and return to his previous every day and sports activities. No recurrence was seen at two years follow-up.

Liposclerosing myxofibrous tumor (LSMFT), a study of 33 patients: should it be a distinct entity?

Liposclerosing myxoid fibrous tumor (LSMFT) is a recently described bone lesion site specific to the proximal femur. We have studied the radiographs and clinical features of 33 patients with this disorder. Histologic material was available for study in 18 of these patients. Histologic study revealed that 12 of these 18 had an underlying fibrous dysplasia and these had an underlying intraosseous lipoma. Because of this histologic evidence as well as the radiographic spectrum of the other lesions, we conclude that LSMFT is not a specific lesion and use of the term should be discontinued.

Imaging interpretation of oncologic musculoskeletal conditions

There is considerable overlap in the clinical and imaging presentation of general orthopaedic conditions and musculoskeletal neoplasms. At centers that treat orthopaedic oncologic conditions, it is not uncommon to see patients with spine and extremity tumors previously treated for presumed general orthopaedic ailments. It is important for orthopaedic surgeons to understand how to interpret commonly ordered radiographic studies (radiographs, MRIs, and CT scans) as they relate to bone and soft-tissue tumors, to be familiar with the imaging appearance of common musculoskeletal lesions in the extremities and spine, and to understand what imaging findings should trigger a referral to an orthopaedic oncologist.

Osteochondral allograft transplantation after excision of femoral head giant cell tumour: a case report

We report a case of Giant Cell Tumour of the femoral head in a 22-year-old man that was excised and reconstructed with an osteochondral allograft. After 3.5 years follow-up, the graft had completely united and there were no signs of recurrence or resorption; the patient had an excellent functional outcome. Osteochondral allograft transplantation may provide a viable option for joint salvage after excision of a benign or locally aggressive tumour in the femoral head in selected cases.

[Clinicopathologic features of primary osteosarcoma in elderly patients]

OBJECTIVE

To study the clinical manifestations, radiologic findings, pathologic diagnosis and differential diagnosis of primary osteosarcoma in elderly patients.

METHODS

Twelve cases of primary osteosarcoma occurring in patients older than 60 years were encountered during the period from 1985 to 2010. The clinical manifestations, radiologic features and pathologic findings were studied and the follow-up data were analyzed.

RESULTS

The sites of involvement included long bones (number = 7), ilium (number = 1), craniofacial bones (number = 2) and soft tissue (number = 2). Radiologic examination showed a mixture of osteosclerotic and osteolytic lesions in 10 patients, soft tissue lesions with high-density areas in 2 patients and soft tissue lesions with periosteal reaction in 8 patients. Histologically, most cases showed features of conventional osteosarcoma. There were 2 cases of malignant fibrous histiocytoma-like osteosarcoma, 2 cases of chondroblastic osteosarcoma and 1 case of well-differentiated intraosseous osteosarcoma. Immunohistochemical study played little role in pathologic diagnosis. Ten patients had undergone amputation, including one patient who had received adjuvant chemotherapy beforehand. Nine patients had follow-up information available. Three of them died of lung metastasis and 1 died of cardiovascular disease.

CONCLUSIONS

Primary osteosarcoma rarely occurs in elderly patients and can easily be missed. Correlation with clinical, radiologic and histologic features is important for arriving at a correct diagnosis.

[Surgical treatment of pertrochanteric femoral benign tumors in children]

INTRODUCTION

Disclosure of the tumor area intertrochanteric femur occurs mostly at the time of pathological fracture. Detection of changes can also be made in conjunction with x-ray of the hip joint such as the hip injury. The purpose of this study was to present the treatment of benign tumors of the intertrochanteric area in children and adolescents.

MATERIALS AND METHODS

From 1. 01. 2002 to 31. 12. 2009 13 patients were treated with benign tumors of the femur intertrochanteric area, including 10 with pathological fractures in the background. Average age was 9.8 years (5-13 years). There were 11 boys and 2 girls. The procedure was performed with resection of the tumor,histopathology, allogenic bone grafting, the femur was fixed using locked plate (10 patients) or angular plate (3 patients).

RESULTS

The mean observation time was 62 months (24-94 months). Histopathology examination showed a simple cyst in 7 patients, aneurysmal cyst in 2 patients, and fibrous dysplasia of bone in 4 patients. Bone consolidation was achieved in 10 patients after an average of 4 months (3-5 months) after surgery, as determined by X-ray examination and clinical examination. In 3 cases there was a recurrence of the tumor, 2 patients with fibrous dysplasia after 4 months and 6 months after surgery were found in X-ray partial resorption of bone graft >25%, and 1 patient after 4 months presented fatigue fracture at Adams angle. After re-treatment complete bone consolidation was achieved in this group after an average of 4 months (2.5-5 months) from the second surgery. 1 patient with aneurysmal cyst in 11 month after surgery, presented femoral infection, sequestrum and plate were surgically removed, antibiotic therapy was used and the inflammatory process was stopped.

CONCLUSION

Surgical treatment of benign tumors of the intertrochanteric area of the femur gives good results if it is carried out by a complex surgery (resection of the tumor - bone graft - osteosynthesis).

Peripheral ossifying fibroma and juxtacortical chondrosarcoma in cynomolgus monkeys (Macaca fascicularis)

Literature on spontaneous primary bone tumors in nonhuman primates is sparse. This case report describes 2 different neoplastic bone lesions in 2 adult cynomolgus monkeys (Macaca fascicularis), including macroscopic, radiographic, histologic, and immunohistochemical findings. In one monkey, a firm mass located at the palatogingival junction of the left rostral maxilla was confirmed to be a peripheral ossifying fibroma in light of its histologic and immunohistochemical characteristics. In another monkey, a lobulated tumor at the right distal femur that radiographically showed moderate radiopacity with splotchy areas of mineralization was confirmed to be a juxtacortical chondrosarcoma on histologic examination. The 2 neoplastic bone lesions revealed rare histologic and immunohistochemical characteristics and contribute to the known tumor spectrum of cynomolgus monkeys.

Chondrosarcoma of the femur with histology-imaging correlation of tumor growth--preliminary observations concerning periosteal new bone formation and soft tissue extension

The objective of this study was, in chondrosarcoma (CHS) of the femur, to evaluate by radiologic-pathologic correlation, the degree of tumor growth, cortical destruction, periosteal reaction, and soft tissue extension present.

MATERIALS AND METHODS

Eight cases of histologically proven CHS of the femur were studied. All cases were resected, evaluated histologically with coronal slabs, and compared with radiographs and magnetic resonance imaging (MRI) scans. In two resected specimens, the tumors were studied in more detail; along with coronal slabs, axial sections of the remaining anterior and posterior halves of both tumors were taken, and the bone specimens were X-rayed and examined histologically.

RESULTS

CHS initially involved the medullary cavity and subsequently destroyed the cortex; first, by endosteal scalloping and, second, by subsequent invasion and destruction of the cortex. During this process, there was periosteal new bone formation (PNBF), with increased cortical thickness, the degree of which often correlated with the degree of cortical destruction. In the areas of cortical thickening of three cases, a "grey line" was seen on MRI that separated the cortex from the periosteal new bone; the line, in reality,is a space between the two structures. The presence of this line suggests that the tumor does not extend beyond the cortex. PNBF occurred in all cases and varied in thickness. It frequently developed independent of direct periosteal tumor involvement. The periosteum of one case contained porotic bone with interposed marrow fat, which was easily misinterpreted as tumor extension on MRI. Expansion and remodeling of the femoral diaphysis in CHS, with widening of the medullary cavity, is usually due to extensive cortical destruction with PNBF. Soft tissue extension was present in five cases and apparently occurred by two different mechanisms: direct tumor destruction of the cortex and periosteum, with extension into the soft tissues; and subtle MRI occult tumor permeation through the periosteum. As far as we know, a first literature histologic description of the thickened CHS periosteum also was accomplished.

CONCLUSION

PNBF is a common imaging manifestation of CHS of the femur, which correlated with the degree of cortical destruction. A grey line between the cortex and periosteum is an MRI finding described in this study and may facilitate the evaluation of periosteal thickening and tumor invasion in CHS. PNBF often occurs in the absence of direct periosteal involvement. Periosteal imaging abnormalities suggestive of tumor infiltration should be interpreted with caution on MRI, and early soft tissue extension in CHS may be difficult to determine on MRI.

Chondrosarcoma of the upper end of the femur

Chondrosarcoma is a malignant tumor that produces cartilage matrix. Occurs in the fourth to sixth decades and has a male to female ratio of 2/1. It is most common in the long bones and on the surface of the pelvis. The authors present a case of chondrosarcoma of the upper end of the femur of a 50-year-old female patient who has come in our Department of Orthopedics and Traumatology two month ago, complaining of severe and persistent pain in the left hip joint and presenting limitation of adduction movement, limitation of internal-external rotation movements, and also could not be able to do thigh flexion on the abdomen. The woman presented a four-month history of persistent and severe pain, not assigned at anti-inflammatory drugs. Laboratory tests not had shown any significance. On radiographies and magnetic nuclear resonance the lesion was shown very clear, deciding for biopsy. The tumor had been large surgical excised with safe limits. Histopathology indicated the histological feature as a differentiated chondrosarcoma, grade III. Our patient has started the chemotherapy and radiation.

[Reconstructive interventions on the hip joint for tumors of proximal part of the femur]

In 41 patients with proximal femur tumors there were studied clinical results of performance of various reconstructive interventions on a hip joint. It was established, that the hip joint endoprosthesis using the cement two-polar total prosthesis had secured the lower extremity function restoration on the level of (84.6 +/- 2.2)%, in arthrodesis--the lower extremity function had restored up to (52.3 +/- 0.5)%. After endoprosthesis an early (in 30% of observations) and late (in 20%) complications had occurred, in arthrodesis the complications were absent.

[Clinicopathologic diagnosis of de-differentiated chondrosarcoma]

OBJECTIVE

To study the clinicopathologic and radiologic features of dedifferentiated chondrosarcoma, focusing on its diagnosis and differential diagnosis.

METHOD

Clinical, radiological and pathologic findings of 14 cases of dedifferentiated chondrosarcoma (including biopsy and surgical specimens) were analyzed by hematoxylin and eosin stained sections and immunohistochemistry.

RESULTS

The mean age of patients was 52 years. The male-to-female ratio was 9:5. The most common sites of involvement were pelvis, femur and humerus, similar to the conventional chondrosarcoma. Radiologically, they were malignant tumors with dimorphic pattern. Grossly, central chondrosarcomas were more common than those of the peripheral. An essential histological feature of dedifferentiated chondrosarcoma was an abrupt interface between the low-grade cartilaginous tumor and high-grade anaplastic sarcoma. The most common dedifferentiated components were osteosarcoma, malignant fibrous histocytoma and fibrosarcoma. False negative diagnosis and erroneous diagnosis were frequent when only one-time biopsy was available.

CONCLUSIONS

Dedifferentiated chondrosarcoma is a rare subtype of chondrosarcoma with poor prognosis, which has different features of clinical manifestation, imaging features and pathological characteristics, compared to conventional chondrosarcoma and chondroblastic osteosarcoma.

[Conservative surgery as an alternative treatment of a knee osteosarcoma in the presence of a pathological fracture]

INTRODUCTION

classical osteosarcoma is defined as a very malignant spindle cell sarcoma, characterized by the production of osteoid matrix, it is the most common primary malignant bone tumor. It is most common among males in their twenties. Factors involved include those related with the skeletal growth and development, pathological fractures, and very young patients who are still growing. Conservative surgery is inappropriate; however, preoperative chemotherapy and a good choice of conservative treatment are an alternative.

MATERIAL AND METHODS

a 15-year-old male patient presented at the orthopedics service with a diagnosis of a pathological fracture in the distal third of the right femur and a tumor in the lateral aspect of the knee, with pain and limitation of gait. Based on X-rays, a bone scan and a biopsy, the diagnosis of a fibroblastic osteosarcoma, an Enneking IIB lesion, was made. Treatment consisted of conservative surgery with broad tumor resection involving 18 cm of the femur, resection of the vastus medialis and vastus lateralis, release of the femoral bundle, the popliteal and sciatic nerves, as well as placement of a modular stryker tumor prosthesis, with knee replacement.

RESULTS

the clinical and radiological course was appropriate. After a 3-week rehabilitation period the patient was able to walk and the lower limb was salvaged. At 5 months there is no evidence of tumor relapse, the patient can walk properly and has recovered the strength.

DISCUSSION

this is a case salvage surgery to treat a pathological fracture resulting from a malignant bone tumor. We think that staging is essential to select the treatment. In the case presented herein a comprehensive management is fundamental to the success of conservative treatment.

[Three-dimensional finite element analysis and biomechanical study on reconstruction of the large defect of proximal femur with allograft prosthesis composite in clinical bone-healing phase]

Three-dimensional finite element models of the large defect of proximal femur were reconstructed with allograft prosthesis composite in clinical bone-healing phase; current model was under the given conditions of 138mm-intramedullary stem-length of host bone and 135mm defect-length of proximal femur. The femur was constructed with efilm software from CT data, then three-dimensional concrete models were created by using Proe-Wildfire software; the three-dimensional finite element models of allograft prosthesis composite were made in ANSYS11 software. Loads were simulated using the peaking values during stance walking. The stress on femur-cement-callus-prostheses and the influence of stress on the clinical bone-healing phase were analysed. The highest stress value of femur is on the medial side of the tip of the prostheses. The highest stress value of cement mantle is on the medical side of the cement mantle at the tip of the stem. The highest stress value of the prostheses is on the medial side near the upper 4cm of the stem tip. The highest stress value on the callus is at the medial side of the callus layer. The highest stress value on every part is under the corresponding fatigue strength. Clinical bone-healing phase model is well enough for stance walking.

[Value of thallium-201 scintigraphy in assessment of neoadjuvant chemotherapy for osteosarcoma]

OBJECTIVE

To investigate the significance of Tl-201 scintigraphy for assessment of neoadjuvant chemotherapy for osteosarcoma.

METHODS

Thirty-four cases with osteosarcoma were enrolled into this study. The Tl-201 scintigraphy features including uptake ratio(UR) and size ratio(SR) were obtained in both early and delay imaging stages before and after chemotherapy. The responses of chemotherapy were classified into three grades according to the percentage of tumor necrosis in the specimens: necrosis < 50% as grade 1, necrosis of 50% approximately 90% as grade 2, diffuse necrosis > 90% as grade 3. The alteration ratio (AR) and SR were calculated according to tumor necrosis ratio (TNR).

RESULTS

Of the 6 patients with grade 1 response, the mean alteration ratios were 3.19% +/- 8.40% and -26.29% +/- 63.61% in early and delay imaging stages, respectively. Among the 18 patients with grade 2 response, the mean alteration ratios were 40.07% +/- 11.95% and 39.30% +/- 9.87%, respectively. Of the 10 patients with grade 3 response, the mean alteration ratios were 78.32% +/- 8.33% and 63.26% +/- 6.06% in early and delay imaging stages, respectively. The results of liner regression analysis of TNR of the surgical specimens showed a significantly positive correlation (r = 0.71) between AR and TNR. The lesion size was reduced in 18 cases, but unchanged in 8 and increased in 8. The liner regression analysis results showed a negative correlation between SR and TNR.

CONCLUSION

The alteration ratio changes significantly after neoadjuvant chemotherapy and has a significantly positive correlation with tumor necrosis ratio. Thallium-201 scintigraphy is helpful in the evaluation of neoadjuvant chemotherapy for osteosarcoma.

Surgical treatment of myelomatosis--a review of 18 cases

The authors review 18 patients with multiple myeloma who had bone destruction of a kind that indicated surgical therapy. Eight patients had paralegic myelopathy and one had compression of the cauda equina. Four of them displayed partial to complete regression. One patient lived for 77 months after the operation, most of the time in excellent condition. The operative technique is discussed, with laminectomy, exeresis, filling of bone with cement and, in some instances, mechanical support from metal plates. Early diagnosis and operation is imperative, postoperative irradiation obligatory in severe cases. Radiation alone may be the method of choice in early stages. The other 9 patients were operated upon for bone destruction in the limbs. A Moore operation on the destroyed hip was performed in one patient, who lived in excellent condition for about four years. Active surgical therapy combined with radiation and cytostatics seems to be of value in many patients with multiple myeloma.

Functional results in patients with sarcoma around the knee joint

Authors evaluated functional outcomes after three different surgical procedures for sarcoma around the knee joint. Sixteen patients with sarcoma were given four to six preoperative courses of chemotherapy. Patients were separated into three groups according to the pattern of tumour excision. The first group underwent the resection of proximal fibula and tibialis anterior muscle resection, the second group underwent resection of distal femur or proximal tibia with total knee replacement, and the third group underwent radical amputation. The mean functional evaluations were 100, 95 and 80%. All marginal resections of proximal fibula resulted in excellent function. No local evidence of tumour recurrence was seen at mean follow-up of 24 months (Tab. 1, Fig. 2, Ref. 7).

Occult large epiphyseal solitary plasmacytoma at multidetector row computer tomography detected by magnetic resonance imaging

Myeloma or Kahler-Bozzolo disease represents around 1% of all malignant tumors and 10% of the haematological variety; it is a B-lymphocellular malignant neoplasia which originates from plasma cells that produce monoclonal immunoglobulin, infiltrating in and destroying the adjacent bone tissue. Myeloma may be distinguished at radiological imaging in four distinct types: single osseous lesions (solitary plasmacytoma), diffused skeletal effects (myelomatosis), diffused osteopenia and sclerosing myeloma. It is known that initial osteolysis may not be shown through radiographic examination or CT; the lysis only becomes evident when there is a bone loss of over 50%, usually in the presence of a > or = 0.5 cm focal lesion. We present here the clinical-radiological aspects of a solitary bone plasmacitoma (SBP) of the knee of a 35 year old male which was not evidenced at radiological examination or CT but was evident as a 3 cm focal alteration at MR. The lesion was confirmed by PET and the histological diagnosis was performed by a CT guided bioptic sample.