[Bone and soft tissue tumours in children : Proposal for a rational diagnostic approach]

CLINICAL/METHODOLOGICAL ISSUE

Bone and soft tissue tumours are often incidental findings in children. Because they are usually benign tumours, nonspecialised radiologists generally have little experience in the diagnosis and differentiation from malignant tumours. Various imaging techniques are used in the diagnosis of skeletal tumours.

STANDARD RADIOLOGICAL METHODS

Imaging techniques used to evaluate bone and soft tissue tumours include sonography, computed tomography (CT) and magnetic resonance imaging (MRI).

METHODOLOGICAL INNOVATIONS

An algorithm to determine malignancy of bone and soft tissue tumours in children is proposed.

PERFORMANCE

By using the presented algorithms, further diagnostic procedures such as biopsies can be avoided in the majority of children with bone and soft tissue tumours. Aggressive bone lesions and unclear soft tissue tumours are guided to biopsy to confirm diagnosis.

ACHIEVEMENTS

The algorithms presented are based on the proposals of European professional societies and have been adapted by the authors for use in children and adolescents.

PRACTICAL RECOMMENDATIONS

In the clarification of soft tissue tumours, sonography is the first diagnostic tool; depending on the sonographic findings, MRI is the technique for further clarification. Biopsy confirmation of the diagnosis in unclear cases or in cases of probable malignancy should be carried out in a paediatric oncology centre.

The knee joint in early juvenile idiopathic arthritis: An ROC study for evaluating the diagnostic accuracy of contrast-enhanced MR imaging

Purpose: Diagnosis of juvenile idiopathic arthritis (JIA) remains difficult due to unspecific clinical and laboratory findings, especially in early stages of the disease. The purpose of our study was to determine the sensitivity and specificity of MR imaging in diagnosing JIA of the knee joints.

Material and Methods: Forty children (3–17 years old) clinically diagnosed with JIA (follow-up >1 year) of a knee joint and a control group of 40 children with painful knee joints (MR diagnosis: bone bruise of the knee (n=7), normal knee joint (n=12), osteomyelitis (n=6), septic arthritis (n=2), bone tumor (n=7) and miscellaneous bone lesions (n=6)) were examined using a 1.5 T MR unit. T1-weighted spin-echo (SE), T2-weighted fast SE, contrast-enhanced T1-weighted SE and 2D gradient echo sequences were performed. The receiver operating characteristic (ROC) curves evaluation was conducted by 5 independent radiologists.

Results: The positive criteria for diagnosing JIA were joint effusions (n=40), contrast-enhancing synovitis (n=39), cartilage lesions (n=15), subchondral erosions and bony destruction (n=1). Sensitivity and specificity were 93.5= and 92.5=, respectively. Both cases of septic arthritis were misdiagnosed as JIA by all radiologists.

Conclusion: Contrast-enhanced MR imaging seems to be a highly sensitive tool in establishing the diagnosis of JIA.

FDG-PET imaging for the staging and follow-up of small cell lung cancer

The staging procedures for small cell lung cancer do not differ appreciably from those for other forms of lung cancer. For practical purposes, the TNM stages are usually collapsed into a simple binary classification: limited disease and extensive disease. This study was performed to answer the question of whether fluorine-18 labelled 2-deoxy-2-D-glucose positron emission tomography (FDG-PET) imaging permits appropriate work-up (including both primary and follow-up staging) of patients presenting with small cell lung cancer, as compared with currently recommended staging procedures. Thirty-six FDG-PET examinations were performed in 30 patients with histologically proven small cell lung cancer. Twenty-four patients were examined for primary staging while four were imaged for therapy follow-up only. Two patients underwent both primary staging and up to four examinations for therapy follow-up. Static PET imaging was performed according to a standard protocol. Image reconstruction was based on an ordered subset expectation maximization algorithm including post-injection segmented attenuation correction. Results of FDG-PET were compared with those of the sum of other staging procedures. Identical results from FDG-PET and the sum of the other staging procedures were obtained in 23 of 36 examinations (6x limited disease, 12x extensive disease, 5x no evidence of disease). In contrast to the results of conventional staging, FDG-PET indicated extensive disease resulting in an up-staging in seven patients. In one patient in whom there was no evidence for tumour on conventional investigations following treatment, FDG-PET was suggestive of residual viability of the primary tumour. Furthermore, discordant results were observed in five patients with respect to lung, bone, liver and adrenal gland findings, although in these cases the results did not affect staging as limited or extensive disease. Moreover, FDG-PET appeared to be more sensitive for the detection of metastatic mediastinal and hilar lymph nodes and bone metastases. Finally, all findings considered suspicious for tumour involvement on the other staging procedures were also detected by FDG-PET. It is concluded that FDG-PET has potential for use as a simplified staging tool for small cell lung cancer.

Distal phalangeal bone cysts: differentiation of enchondromata and epidermal cysts

Enchondromas are common in the hand but less frequent in the distal phalanges. Epidermal cysts are rare in the hand but when they occur can be difficult to differentiate from enchondromas both clinically and radiologically. Our review of seven distal phalangeal bone lesions treated over 7 years included four enchondromas and three epidermal cysts. The patients with epidermal cysts all had a history of previous penetrating trauma 5-8 years earlier. One patient with an enchondroma had a history of a penetrating injury. Patients presenting with distal phalangeal lesions and a history of previous penetrating injury appear more likely to have an epidermal cyst than an enchondroma. This is important as there may be a higher recurrence rate following curettage and bone grafting.

Comparison of total and partial traumatic tears of the subscapularis tendon

We treated surgically 16 shoulders with an isolated traumatic rupture of the subscapularis tendon over a six-year period. Nine patients had a total and seven a partial tear of the subscapularis tendon. Repair was undertaken through a small deltopectoral groove approach. The mean Constant score improved in total tears from 38.7 to 89.3 points (p = 0.003) and in partial tears from 50.7 to 87.9 points (p = 0.008). The total tears were significantly more improved by surgery than the partial tears (p = 0.001). The delay between trauma and surgery was inversely proportional to the improvement in the Constant score suggesting that early diagnosis and surgical repair improves outcome.

The knee joint in early juvenile idiopathic arthritis. An ROC study for evaluating the diagnostic accuracy of contrast-enhanced MR imaging

PURPOSE

Diagnosis of juvenile idiopathic arthritis (JIA) remains difficult due to unspecific clinical and laboratory findings, especially in early stages of the disease. The purpose of our study was to determine the sensitivity and specificity of MR imaging in diagnosing JIA of the knee joints.

MATERIAL AND METHODS

Forty children (3-17 years old) clinically diagnosed with JIA (follow-up > 1 year) of a knee joint and a control group of 40 children with painful knee joints (MR diagnosis: bone bruise of the knee (n = 7), normal knee joint (n = 12), osteomyelitis (n = 6), septic arthritis (n = 2), bone tumor (n = 7) and miscellaneous bone lesions (n = 6)) were examined using a 1.5 T MR unit. T1-weighted spin-echo (SE), T2-weighted fast SE, contrast-enhanced T1-weighted SE and 2D gradient echo sequences were performed. The receiver operating characteristic (ROC) curves evaluation was conducted by 5 independent radiologists.

RESULTS

The positive criteria for diagnosing JIA were joint effusions (n = 40), contrast-enhancing synovitis (n = 39), cartilage lesions (n = 15), subchondral erosions and bony destruction (n = 1). Sensitivity and specificity were 93.5% and 92.5%, respectively. Both cases of septic arthritis were misdiagnosed as JIA by all radiologists.

CONCLUSION

Contrast-enhanced MR imaging seems to be a highly sensitive tool in establishing the diagnosis of JIA.

Liposarcoma

Using nuclear suspensions, the DNA-content of 7 bone-associated, paraffin-embedded liposarcomas and 3 lipomas were examined by means of flow cytometry (FCM) and was compared with the results of image cytophotometric measurements (ICM). Using ICM, 6 of 7 liposarcomas showed an aneuploid DNA content (86%), whereas FCM showed aneuploidy in 3 cases (43%). None of the lipomas had an aneuploid DNA-content using either method. The correspondance of the two methods was 70%. Because aneuploidy is of prognostic importance, ICM could be the method to determine the DNA content of liposarcoma.