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Notes: Zusammenfassung Mit Hilfe kombinierter biochemischer und zytophotometrischer DNS-Messungen wurde die Anzahl der Herzmuskelzellen in Menschenherzen bestimmt. Normale Menschenherzen (330 g) haben nach dieser Berechnung 2×109 Muskelzellen. In hypertrophierten Herzen (500–900 g) nimmt die Zellzahl bis auf 4 × 109 Muskelzellen zu.

Notes: Abstract. The aim of our study was to correlate MRI with histologic findings in normal and degenerative cartilage. Twenty-two human knees derived from patients undergoing amputation were examined with 1.0- and 1.5-T MR imaging units. Firstly, we optimized two fat-suppressed 3D gradient-echo sequences. In this pilot study two knees were examined with fast imaging with steady precession (FISP) sequences and fast low-angle shot (FLASH, SPGR) sequence by varying the flip angles (40, 60, 90 °) and combining each flip angle with different echo time (7, 10 or 11, 20 ms). We chose the sequences with the best visual contrast between the cartilage layers and the best measured contrast-to-noise ratio between cartilage and bone marrow. Therefore, we used a 3D FLASH fat-saturated sequence (TR/TE/flip angle = 50/11 ms/40 °) and a 3D FISP fat-saturated sequence (TR/TE/flip angle = 40/10 ms/40 °) for cartilage imaging in 22 human knees. The images were obtained at various angles of the patellar cartilage in relation to the main magnetic field (0, 55, 90 °). The MR appearances were classified into five categories: normal, intracartilaginous signal changes, diffuse thinning (cartilage thickness 〈 3 mm), superficial erosions, and cartilage ulcers. After imaging, the knees were examined macroscopically and photographed. In addition, we performed histologic studies using light microscopy with several different stainings, polarization, and dark field microscopy as well as electron microscopy. The structural characteristics with the cartilage lesions were correlated with the MR findings. We identified a hyperintense superficial zone in the MR image which did not correlate to the histologically identifiable superficial zone. The second lamina was hypointense on MRI and correlated to the bulk of the radial zone. The third (or deep) cartilage lamina in the MR image seemed to represent the combination of the lowest portion of the radial zone and the calcified cartilage. The width of the hypointense second zone correlated weakly to the accumulation of proteoglycans in the radial zone. The trilaminar MRI appearance of the cartilage was only visible when the cartilage was thicker than 2 mm. In cartilage degeneration, we found either a diffuse thinning of all layers or circumscribed lesions (“cartilage ulcer”) of these cartilage layers in the MR images. Early cartilage degeneration was indicated by a signal loss in the superficial zone, correlating to the histologically proven damage of proteoglycans in the transitional and radial zone along with destruction of the superficial zone. We found a strong effect of cartilage rotation in the main magnetic field, too. A rotation of the cartilage structures caused considerable variation in the signal intensity of the second lamina. Cartilage segments in a 55 °angle to the magnetic main field had a homogeneous appearance, not a trilaminar appearance. The signal behavior of hyaline articular cartilage does not reflect the laminar histologic structure. Osteoarthrosis and cartilage degeneration are visible on MR images as intracartilaginous signal changes, superficial erosions, diffuse cartilage thinning, and cartilage ulceration.

Notes: Summary A case of a 19-year-old female patient with a primary B-cell lymphoma of bone is presented. Although extensive diagnostic procedures including CT and MRI scans as well as bone histology were used, the case was initially misdiagnosed as chronic osteomyelitis. Resection of the distal femur including the knee joint was performed and bisegmental callus distraction was initiated. After local exacerbation a B-cell lymphoma was diagnosed histologically and immunohistochemically in a soft tissue specimen. Above-knee amputation had to be carried out due to severe local soft tissue necrosis and superinfection. Diagnostic problems arose from non-specific clinical symptoms, uncertain radiographic signs and non-diagnostic histology. Growth factors may have stimulated tumor growth after initiation of callus distraction.

Notes: Abstract It has been well documented in laboratory animals that β-sympathicomimetics, such as isoprenalin, can cause myocardial lesions. Other so called “β2-selective” symphaticomimetic drugs, which nevertheless induced β1-cardiostimulatory side effects, are now widely used for suppression of premature labor. We examined the hearts of 25 newborns whose mothers had been treated with β-sympathicomimetics for various lengths of time (24 h to 8 weeks). Three types of lesions were detected: (1) focal subendocardial necroses (3 cases), similar to isoprenalin-induced myocardial necroses in animal experiments, (2) diffuse fatty degeneration of myocardial cells (3 cases), and (3) nuclear polyploidization in the subendocardial layer of the right ventricular wall (14 cases). However, the immediate causes of death could not be directly related to the tocolytic treatment in any of the cases.

Notes: Abstract DNA content, ploidy level, cell size and nuclear number were investigated in 54 mammalian hearts from nine species. DNA content was determined biochemically and ploidy level of cells was studied by the means of Feulgen cytophotometry. Nuclear number was calculated by a new method, while cell size was determined by using ocular micrometry. In most mammals diploid cell nuclei predominate. Higher ploidy levels were found in the human and the pig hearts. The total amount of DNA correlated with the myocardial weight. Eight million heart muscle cell nuclei were found in mice (myocardial weight 160 mg), and 2600 million heart muscle cell nuclei in the human heart (myocardial weight 210 g), but in the hearts of horses up to 35 000 million heart muscle cell nuclei (myocardial weight 3.4 kg) were found. The number of heart muscle and connective tissue cell nuclei was correlated with myocardial weight. The ratio of connective tissue cell nuclei to heart muscle cell nuclei was between 2:1 and 3:1. In cardiac growth this ratio shifted towards connective tissue cell nuclei. Increased heart weight corresponds to an increase in cell size. Diameter between 11 μm and 18 μm may be an optimum for heart muscle cells of mammals.

Notes: Summary A case of fibromyxoma of the long bone is presented. This benign bone tumor is more often found in the bones of the jaw, but is a rare lesion in extragnathic bones. In the presented case of a 28-year-old man the tumor was situated in the right femoral neck. In the roentgenograms it showed a cast-like osteolytic defect with unclear marginal sclerosis and patchy densities within the lesion. Histologically, the tumor consisted of a proliferating hypocellular myxomatous tissue with some focal calcification and fibrous areas. No chondroid pattern was present and there was no clear lobulation. Differential diagnostic considerations include ganglia of bone, chondromyxoid fibroma, chondrosarcoma and fibrosarcoma, all of which may contain prominently myxoid zones.

Notes: Summary Massive osteolysis is a very rare tumour-like lesion usually affecting young adults. There are 132 reported cases which we have reviewed, including 31 single cases of pelvic involvement. The term “massive osteolysis” is based on the typical radiological findings, such as increasing translucency and loss of bone density. The diagnosis of the Gorham-Stout syndrome must be confirmed by the microscopic finding of intramedullary vascular structures. Our patient was a 23 year old white Caucasian, who had the full clinical signs of Gorham-Stout syndrome. She had achieved 2 normal pregnancies and deliveries in spite of her massive pelvic osteolysis.

Notes: Summary Haemangiosarcoma of bone is a very rare primary tumour with a variable history and differing radiographic and histological appearances. In some cases the lesion has similar features to the so-called “adamantinoma of long bones” in which the histogenesis is also unknown. Such a lesion is described which ocurred in the shaft of the right humerus of a 31-year-old man. Radiographically a centrally located area of osteolysis was seen without marginal sclerosis, but with erosion of the bony cortex. A biopsy was performed 16 months after the first radiographic examination and showed malignant tumour tissue which was difficult to classify histomorphologically. Several different neoplasms such as Ewing's sarcoma, myeloma, liposarcoma, malignant fibrous histiocytoma or a bone metastasis were suggested. Finally, a haemangiosarcoma or so-called “adamantinoma of long bones” was considered. The tumour was completely removed by en-bloc resection. Careful histomorphological investigation of the tumour tissue by means of light microscopy, cytology and electronmicroscopy showed a vascular pattern characteristic of a haemangiosarcoma. Using cytophotometric DNA measurements of the tumour cells, the lesion could be classified as being of lowgrade malignancy. This is confirmed since there has now been a 4-year follow up with no local recurrence or metastasis. There are many similarities between a well-differentiated haemangiosarcoma and an “adamantinoma of long bones”. The differential diagnosis and the histogenesis of the latter lesion is discussed. It is emphasized that the so-called “adamantinoma of a long bone” probably has a vascular origin.

Notes: Abstract  Osteoblastoma is a benign bone tumor with uncertain radiologic and typical histologic pattern that, in most cases, can be diagnosed without any problems. Usually, it is a solitary bone tumor. The case presented is a 9-year-old child with multiple osteoblastomas occurring in multiple bones of the right hand. The child had pain in his right hand for several weeks. On physical examination, no swelling or other symptoms were elicited. All lesions noted radiologically were treated by curettage, and in all the pattern of osteoblastoma was diagnosed.