[Tumor-like lesions of bone]. / Tumorähnliche Knochenläsionen.

Historically, tumor-like lesions of bone were defined as non-neoplastic bone lesions. Today, however, some of them are considered real neoplasms. They are among the most frequent bone lesions. They usually grow slowly, but occasionally they grow rapidly. Many of them can be diagnosed by plain films alone; in others, CT and MRI yield additional features for a correct diagnosis. Some lesions do not need treatment; others should be resected, and some may even recur. Non-ossifying fibroma, juvenile and aneurysmal bone cysts, fibrous and osteofibrous dysplasia and eosinophilic granuloma are presented.

[MRI morphology of bone tumors and tumor-like lesions]. / MRT-Morphologie von Knochentumoren und tumorähnlichen Läsionen.

Spin-echo sequences are mandatory at MRI for staging and characterization of bone tumors and tumor-like lesions. MRI is of minor value in the estimation of the malignant potential of an osseous lesion. Although many bone tumors and tumor-like lesions present similar morphology at MRI, some entities can be diagnosed with good reliability. These include chondrogenic tumors, solitary and aneurysmal bone cysts, giant cell tumors, lesions containing fatty tissue and, to a certain extent, osteoid-osteomas and osteoblastomas. Practical advice is given regarding when to perform a MRI study in cases of tumor suspicion. Further advice is given for cases a tumor is found incidentally at a MRI study, how to modify the study and which kind of tumor may be present.

[Basic diagnostics of bone tumors]. / Basisdiagnostik von Knochentumoren.

Primary bone tumors and tumorlike lesions are rare. However, they are found on x-ray incidentally or during examination of a painful skeletal region. This article explains how to diagnose such a detected lesion. Primarily, the growth rate is analyzed according to the Lodwick classification to differentiate a benign from a malignant lesion. With that, the lesser experienced clinician has solved the most important task in the diagnostic process. Further steps include analysis of the tumor matrix and the location within the tumor-bearing bone to make a specific diagnosis. Finally, the patient's age is included as a further parameter. With an optimized combination of the different parameters, the expert achieves a correct specific diagnosis in about 80% of cases.

Imaging and differential diagnosis of primary bone tumors and tumor-like lesions of the spine.

Primary bone tumors and tumor-like lesions of the spine and sacrum are rare. A wide variety of benign and malignant lesions can arise in the spine and sacrum. Specific diagnosis is based on the location, matrix appearance and patient's age at time of presentation. In this location CT is often necessary for matrix characterization, particularly, detection of mineralization. MRI can be helpful for further characterization and radiological differential diagnosis. An overview of age distribution and imaging features including pattern for differential diagnosis is presented for the most frequent primary spinal bone tumors and tumor-like lesions.

(Sub)periosteal Ewing's sarcoma of bone.

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

Spindle cell (leiomyomatous) rhabdomyosarcoma, a rare variant of embryonal rhabdomyosarcoma.

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

"Solid" variant of aneurysmal bone cyst.

A case of the so-called "solid" variant of aneurysmal bone cyst is reported. A 12-year-old girl with a few weeks' history of backache presented with a tender palpable mass located thoraco-spinal in the back at Th 3. Radiologically, the lesion was consistent with conventional aneurysmal bone cyst. Morphologically, it showed fibroblastic, fibrohistiocytic, fibromyxoid, osteoclastic and osteoblastic components as well as small aneurysmal sinusoids. Based on four other well documented cases, the clinico-pathological features and the differential diagnostical problems are discussed.

[Tumorous space-occupying lesions of the pelvic skeleton. A radiological analysis of 234 cases]. / Tumoröse Raumforderungen des Beckenskeletts. Eine radiologische Analyse von 234 Fällen.

PURPOSE: From the material of a bone tumour record file, an attempt was made to determine criteria enabling radiographic prediction of malignancy and tumour entity of lesions of the pelvis. METHODS: Patients' age, location and radiographic morphology of 234 space-occupying lesions of the pelvis were analysed retrospectively. RESULTS: 62.8% of all lesions were malignant, and the portion of malignant tumours increased with increasing age. While 68.0% of the lesions were found in the ilium, 18.8% in the pubis and 13.2% in ischium, the proportion of benign and malignant lesions did not vary in the different bones. Lesions showing a growth rate according to Lodwick grade IA and to IB were benign in 100% and in 82.0%, respectively. In contrast, tumours of grade II or III were malignant in 89.1% and 88.0% of cases, respectively. CONCLUSIONS: By the construction of subgroups by combining the patients' age and growth rate, the prediction of the malignant potential of a lesion increased significantly. The younger the patient, the more aggressively a benign lesion may grow, while the older the patient the slower a malignant tumour may grow. Prediction of the tumour entity is rarely possible.

[Efficient use of flash sequences in the staging of bone and soft tissue tumors]. / Rationeller Einsatz von Flash-Sequenzen im Staging von Knochen- und Weichteiltumoren.

Delineation of neoplasms from normal tissue is possible using Flash sequences. These sequences prove useful in preoperative staging of bone tumours and soft tissue tumours. However, contrast between neoplastic and surrounding normal tissue is lower than in optimal selected spin-echo sequences. Flash-90 sequence is superior to Flash-10 sequence in the demonstration of intraosseous extension of predominantly sclerotic, calcified and purely fibrous tumours. In contrast, Flash-10 sequence proves superior for the demarcation of osteolytic tumours with minimal fibrous tissue content. Delineation of extraosseous tumour masses against muscle can best be achieved using Flash-90 sequence after intravenous administration of Gadolinium-DTPA. Flash-90 sequence enables sharp demarcation of extraosseous masses of bone tumours against surrounding fat, whereas Flash-10 sequence proves useful in the delineation of non-lipomatous soft tissue tumours against normal fat.

[Contrasts in the FLASH sequences in the study of musculoskeletal tumors: phantom study and theoretical calculations]. / Kontraste in FLASH-Sequenzen bei der Untersuchung von muskuloskelettalen Tumoren: Phantomstudie und theoretische Berechnung.

The contrast between samples simulating musculoskeletal neoplasms and muscle or bone marrow achieved with FLASH sequences, was analysed in phantom studies and was compared with theoretically calculated contrast with and without correction for flip angle distribution over the slice profile. The contrast was correlated closer with the flip angle than with TR or TE. For delineation of the tumour from muscle, only a FLASH sequence with a large flip angle following intravenous administration of Gd-DTPA can be recommended, if a tumour shows a clear Gd-DTPA uptake. With all FLASH sequences analysed, no sufficient contrast between "tumour" without Gd-DTPA uptake and muscle was obtained. Maximal contrast between "tumour" and bone marrow was achieved with small flip angles; and an additional peak was noted with large flip angles and short TR. Experimentally measured T2*-dependent contrasts were nearly identical with theoretically calculated contrasts without correction of flip angle distribution. For calculation of T1-dependent contrasts, correction of the flip angle distribution over the slice profile was of high value.

[Aneurysmal bone cyst or giant cell tumor. The value of x-ray diagnosis for differential diagnosis]. / Aneurysmatische Knochenzyste oder Riesenzelltumor. Wertigkeit der Röntgendiagnostik zur Differentialdiagnose.

Depending on analysis of radiographic morphology, location and patient's age of 72 aneurysmal bone cysts (ABC) and 47 giant cell tumours (GCT), the following criteria suggest an ABC with a high positive predictive value: location in the diaphysis (100%), in the shaft (92%), in the metaphysis or metadiaphysis (86%), patient younger than 17 years (97%) and growth rate grade Lodwick-IA (88%). GCT were selected via the following criteria: epimetaphyseal location (82%) and growth rate grade Lodwick-II (100%). In 14% of the cases, differential diagnosis between both entities is radiologically impossible.

[Tumorous space-occupying lesions of the tibia. A radiological analysis of 459 cases]. / Tumoröse Raumforderungen der Tibia. Eine radiologische Analyse von 459 Fällen.

The patients' age, location and radiography of 459 bone tumours and tumour-like lesions of the tibia were analysed retrospectively. 79.2% of all lesions were benign, and the portion of malignant tumours increased with increasing age. Predominantly malignant tumours were found in a distal central metadiaphyseal (100%), in proximal central epimetadiaphyseal (90%) and in a proximal central metadiaphyseal (63%) location. Lesions showing a growth rate according to Lodwick IA and those to IB were benign in 99.5% and in 95.4%, respectively. In contrast, tumours showing a grade II or III were malignant in 85.2% and 100% of cases, respectively. Through the construction of subgroups by combination of patients' age, location and growth rate special tumours were selected in that way, that they were predominantly found in that subgroups.

[The MR tomography of hemophilic osteoarthropathy with special reference to the synovial and chondrogenic changes]. / MR-Tomographie der hämophilen Osteoarthropathie unter besonderer Berücksichtigung der synovialen und chondrogenen Alterationen.

52 knee and ankle joints of hemophiliacs were examined by MRI using FLASH and FISP-3-D sequences; and the degree of synovial hypertrophy and of cartilage destruction were assessed. Findings of synovial hypertrophy varied between thin membranes and tumorous tissue destroying the joint cartilage. Degree of cartilage destruction varied between focal signal decrease and total loss. In spite of recurrent joint bleedings no synovial or cartilaginous changes were seen in 31% and 29% of joints, respectively. Changes were more frequently seen and degree was more marked in the ankle than in the knee joints. With the exception of cysts, osseous destruction was more obvious with radiographs. MRI is suitable for the investigation of joints of hemophiliacs showing no osseous destruction.

[Imaging of femur head necrosis using MR tomography]. / Die Darstellung der Femurkopfnekrose in der MR-Tomographie.

Magnetic resonance tomography (MR) was used to examine the femoral heads of 20 normals and of 56 patients with diseases of the femoral head, including Perthe's disease (four cases), adult necrosis of the femoral head (39 cases) and pain of unknown cause (13 cases). Femoral head necrosis and Perthe's disease regularly produce reduced signal intensity. The localisation of the areas of necrosis can be determined accurately in the coronary and sagittal plane. In 11 femoral heads, necrosis could be demonstrated unequivocally by MR in the presence of normal radiographic findings. Follow-up of nine patients with negative MR findings and indefinite symptoms confirmed the absence of necrosis.

[Space-occupying tumor lesions of the spinal column. An analysis of the material submitted to the Westphalia Bone Tumor Register]. / Tumoröse Raumforderungen der Wirbelsäule. Eine Analyse des Einsendematerials des Knochengeschwulstregisters Westfalen.

308 tumorous lesions of the spine were identified in the material submitted to the bone tumour register in Münster for recording. Histological examination revealed metastases in 38.6% primary bone tumours in 33.1%, tumour-like lesions in 10% and haematological and lymphatic disease in 13%. 5.3% of all lesions could not be classified in these groups. Primary bone tumours were seen more often than metastases in the cervical spine, the sacrum and the coccyx. 54.9% of the primary bone tumours of the spine were benign. However, only 31.2% of all the tumorous lesions of the spine, metastases included, were benign. The portion of malignant disorders increased with increasing age. The risk of having a malignant spine tumour was 5.9% in patients under 10 years of age but 92.3% in patients in the seventh decade.

[Computed tomography changes in children with shunted hydrocephalus and intermittent cranial pressure crises]. / Computertomographische Veränderungen bei Kindern mit drainiertem Hydrozephalus und intermittierenden Hirndruckkrisen.

Seven children with drained hydrocephalus are described who showed increasingly severe and frequent episodes of intermittently raised intracranial pressure. CT examinations during symptom-free intervals, or after conservative treatment, showed collapsed slit-like ventricles. Examination during attacks of raised pressure showed relative dilatation of the ventricles as compared with earlier examinations. Children with ventricular shunts of long duration may develop a shunt-dependent syndrome; CT may show normal or narrow ventricles and this does not exclude the possibility of a rise of intracranial pressure. These findings may help in making the diagnosis by means of CT without any further invasive procedures.

[Staging of hemophilic osteoarthropathy using the Pettersson score. A study of 40 children and adolescents]. / Stadieneinteilung der hämophilen Osteoarthropathie mit dem Pettersson-Score. Eine Untersuchung von 40 Kindern und Jugendlichen.

The degree of haemophilic osteoarthropathy was assessed by the Pettersson-score in 219 knees, elbows and ankles of 40 children and adolescents suffering from haemophilia. 55.3% of the joints were unaffected and only 8 joints showed score values greater than 8. Enlargement of epiphyses (36.1%) and irregular subchondral surface (32.9%) were the most frequent observations, while osteoporosis (5.4%) was only rarely observed. Haemophilic osteoarthropathy was most severe in the ankles, while the knees were only moderately affected. Among 11 patients 493 bleedings into 61 joints were observed during a four-year period. If the bleedings recurred, more than 3 bleedings per year always resulted in haemophilic osteoarthropathy.

[The x-ray morphology of chondromyxoid fibroma]. / Röntgenmorphologie des Chondromyxoidfibroms.

29 cases of chondromyxoid fibroma (CMF) from the material submitted to the Bone Tumour Register in Münster were reviewed. The tumour was observed most frequently in the second and third decades of life, with a slight female preponderance in our series. The diaphyseal and metaphyseal regions of the lower limb were most commonly affected, with a particular predisposition for the knee. The lesions were located eccentrically in 71% showed cortical expansion in 72%, and pseudotrabeculation in 51% of cases. The lytic patterns were classified as Lodwick IA in 35%, as Lodwick IB in 45%, as Lodwick IC in 17% and as Lodwick II in 3% of cases. Due to the absence of characteristic radiographic features, the differential diagnosis from aneurysmal bone cyst, giant cell tumours and non-ossifying fibroma is often difficult. Radiographic findings would however indicate benignity and, therefore, help to differentiate the lesion from chondrosarcoma, to which it bears strong histological similarity.

[The x-ray morphology of parosteal osteosarcoma (POS)]. / Röntgenmorphologie des parossalen Osteosarkoms (POS).

31 cases of parosteal osteosarcoma (POS) including both the differentiated and dedifferentiated variant were reviewed. Most patients were in the second and third decades of life. The tumours usually arose in the meta-diaphyseal (52%) and diaphyseal (33%) portion of long bones with a predilection for the knee (55%). Twenty-seven percent of patients showed involvement of the medullary cavity. 68% of lesions affected the bone cortex. A periosteal reaction was observed in 24% of patients. The characteristic but not pathognomic sign of a fine radiolucent line separating the tumour from the cortex was seen in only 48%. No characteristic radiographic features were evident that allowed a differentiation between the differentiated and the dedifferentiated POS. The presence or absence of medullary involvement was no a reliable diagnostic criterion. In all dedifferentiated POS, however, we observed a periosteal reaction.

[Localization dependent patterns of findings in chondroblastoma]. / Lokalisationsabhängige Befundmuster beim Chondroblastom.

In a retrospective study the radiographs of 48 chondroblastomas from the files of the Bone Tumour Registry of Westphalia were evaluated. The purpose of the study was to investigate whether chondroblastomas display localisation-dependent radiographic patterns. All radiographs were analysed using the Lodwick criteria. All chondroblastomas (mean age: 18 y., m:f = 1.25:1) showed a geographic pattern of bone destruction. 32 lesions affected long bones, 10 short bones, and 6 flat bones. Chondroblastomas localised in flat bones (Lodwick IA: 0%, IB: 33%, IC: 67%) demonstrated more aggressive patterns of bone destruction compared to lesions affecting long bones (Lodwick IA: 56%, IB: 31%, IC: 13%) or short bones (Lodwick IA: 40%, IB: 50%, IC: 10%). There was no difference between the three bone types in other radiographic patterns (periostitis, calcification, trabeculation).