Hiroshi Orui

Chondro-osseous differentiation in fat tissue tumors: magnetic resonance imaging with pathological correlation

Abstract Chondro-osseous differentiation of three benign or malignant fat tissue tumors – two chondrolipomas and a liposarcoma with cartilaginous metaplasia – was studied with magnetic resonance (MR) imaging and compared with their pathological findings. The results suggest that demarcation of cartilage tisssue can be clearly defined on MR imaging when the size of the cartilaginous area is large. Myxoid matrix, degenerative fat tissue and lipodystrophic change may decrease the delineation of the cartilage tissue.

Proliferation and apoptosis of follicular lymphocytes: relationship to follicular dendritic cell-associated clusters.

Experiments were designed to determine the in vivo cell‐cycle phase of lymphocytes in secondary lymphoid follicles, and whether B‐cell proliferation and apoptosis occur within follicular dendritic cell (FDC)‐associated clusters. Using frozen serial sections of human tonsils, lymphoid follicles were stained to reveal histone H3 mRNA, as an S‐phase marker, using in situ hybridization, and stained immunohistochemically with antibodies against cyclin E as a late G1 phase marker, cyclin B1 and p34cdc2 as S‐G2‐M phase markers, and Ki‐67 as a marker of cycling cells. Each LF was divided into five zones: mantle zone, outer zone, apical light zone, basal light zone and dark zone, with the help of haematoxylin and eosin staining, and a CD23 immunostain. The rate of occurrence of positively labelled cells was calculated by dividing the number of positive cells by the number of all cells in each zone. The cells that were positive for cyclin E, histone H3 mRNA, cyclin B1, p34cdc2, and Ki‐67 were found most frequently in the dark zone (54·5±6·6%, 22·0±5·7%, 36·7±14·5%, 40·0±10·2%, and 59·0±13·4%, respectively), followed by the outer zone (52·7±7·8%, 14·9±4·1%, 22·9±9·7%, 24·9±7·9%, and 44·6±12·3%, respectively), showing that both the outer zone and the dark zone contain many proliferating lymphocytes. Furthermore, FDC‐associated clusters and free lymphocytes were obtained from enucleated germinal centres, using enzymatic digestion. The rates of occurrence of cells that were positive for cyclin B1 and Ki‐67 within the clusters (7·2±1·9% and 37·9±10·5%, respectively) were significantly lower than those of free lymphocytes outside the clusters (22·2±4·0% and 62·8±14·0%, respectively). The rates of occurrence of apoptotic bodies and cells within the clusters, as detected by in situ tailing or in situ nick translation (0·2±0·4% and 0·4±0·4%, respectively) were significantly lower than those outside the clusters (1·1±0·3, 1·6±0·5 %, respectively). These results suggest that FDC‐associated clusters are not the site of proliferation, and that they rarely contain apoptotic bodies and cells of B lymphocytes.

Calcifying fibrous pseudotumor : A case report

Calcifying fibrous pseudotumor is a rare, benign, tumorlike lesion that is composed of fibrous tissue with diffuse deposits of calcium and infiltration of inflammatory cells. We report the case of a girl who had such a lesion in the shoulder girdle. Histopathological examination revealed circulatory disturbances, including narrowing of the feeding artery with thickening of the wall, hyalinization of collagen fibers around the capillaries, and thrombi in the capillaries. A thirteen-year-old girl was seen in June 1995 because of a mass in the left shoulder girdle that she had first noticed a month before. The patient had been a pitcher for a softball team but had no history of major traumatic injury. She had slight pain with movement and had not noticed any recent increase in the size of the mass. She had a history of congenital dislocation of the hip, but there was no family history of such dislocation. Physical examination revealed a six by six-centimeter, hard, mobile, tender mass between the eminence of the deltoid and the lateral head of the triceps. Plain radiographs (Fig. 1-A) and computerized tomography scans (Fig. 1-B) revealed a lobular mass. Magnetic resonance images revealed a well demarcated lobular mass between the deltoid and the lateral head of the triceps; the border between the mass and the surrounding muscles was well marginated in most areas but was poorly defined in some areas. On T1-weighted images, the signal intensity of the mass was equal to that of the surrounding muscles, with irregularly striped areas of low signal intensity that were suggestive of calcification (Fig. 2-A). On T2-weighted images, the mass had low signal intensity with irregularly scattered areas of high signal intensity (Fig. 2-B). On T1-weighted images that were enhanced with gadolinium-diethylenetriamine pentaacetic acid, the mass had high signal intensity with irregular focal areas …

Radiological features of long bones in synovitis, acne, pustulosis, hyperostosis, osteitis syndrome and their correlation with pathological findings

Abstract The purpose of this study was to demonstrate the radiological features of long bones in synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome and to correlate these with the clinical findings. Eleven long bone lesions in seven cases of SAPHO syndrome were examined. The patients ranged in age from 6 to 63 years, with a mean of 47 years. In all seven cases, radiography, 99mtechnetium bone scintigraphy, CT scan, and magnetic resonance imaging (MRI) were performed. In six of the cases, bone biopsy and bone culture were carried out for 7 long bones. Seven of the involved lesions were from the shaft of the femur, one each was from the neck and the shaft of the humerus, and one was from the proximal tibia. These lesions showed radiologically hyperostosis, osteolysis, and bone infarction-like lesion. Osteolysis was occasionally accompanied by sclerotic change. Hyperostosis usually showed diaphyseal involvement, presenting low signal intensity on T1- and T2-weighted MR images. Histologically, these findings corresponded to massive bone necrosis, new bone formation, fibrosis, or a mixture of these associated with mild inflammatory cell infiltration. Osteolysis involved dyaphysis, metaphysis, or epiphysis associated with arthritis, and presented low signal intensity on T1-weighted images, nonhomogeneous signal intensity lower than fat on T2-weighted images, and high signal intensity on fat suppression images. These findings corresponded to fibrosis, granulation, and inflammatory cell infiltration with lymphocyte aggregation. Bone infarction-like lesion was observed in the shaft or neck of the femur and the humerus and accompanied by calcification and cystic change. Bone cultures were negative in all cases in which bone biopsy was performed. Although hyperostosis is thought to be a characteristic bone lesion in SAPHO syndrome, the long bone lesion can occasionally show not only hyperostosis but also osteolytsis and bone infarction-like lesions.

The response of costal cartilage to mechanical injury in mice.

Background: The healing potential of articular cartilage in response to injury is poor, because articular cartilage lacks blood vessels or perichondrium. Costal cartilage is covered with a vascularized perichondrium, which is known to have chondrogenic potential. The purpose of this study was to determine whether costal cartilage can heal in response to mechanical injury. Methods: Sixty-five ICR mice were used. Under anesthesia, the left tenth costal cartilage was dissected using microscissors. At 1 day and at 1, 2, 3, and 12 weeks after injury, the mice were killed and paraffin sections were prepared. Safranin O staining, in situ hybridization of type II collagen, and immunostaining for CD44 were performed. Localization of cell proliferation was performed using immunohistochemistry with bromodeoxyuridine monoclonal antibody. In situ detection of apoptosis (deoxynucleotidyl transferase-mediated dUTP nick end labeling) was performed using an Apop Tag Kit. Results: From 1 to 2 weeks after costal cartilage injury, bromodeoxyuridine-positive cells were observed in the perichondrium. Two weeks after injury, the dissected cartilage fragments had combined with newly formed safranin O–positive tissue. Type II collagen mRNA was strongly expressed in the cells of the newly formed tissue. Apoptosis was detected in newly formed cartilaginous tissue at 1 and 2 weeks after injury. The cartilage fragments failed to unite at 12 weeks after injury. CD44 immunoreactivity was detected on the surface of the cavity between the cartilage fragments. Conclusion: Although the dissected fragments of costal cartilage can combine with newly formed cartilaginous tissue temporarily, they fail to unite ultimately.

Lipoblastoma with aberration in the long arm of chromosome 8.

Abstract We report a case of lipoblastoma in a 6-month-old girl with a new chromosomal aberration, 46, XX, der (2) add (2) (p23) del (2) (q33), add (8) (q1?). In addition to the patients age and pathological features, aberration of long arm of chromosome 8 in lipoblastoma can assist the differential diagnosis from myxoid or well differentiated liposarcoma.

Malignant intramuscular forearm tumor with overwhelming squamous element

Squamous cell carcinoma (SCC) arising in the skeletal muscle is rare. A case of a 19‐year‐old female patient with an intramuscular forearm tumor showing a histopathologically overwhelming squamous element is presented. Microscopic examination revealed the classical features of SCC, including horn pearls, individual cell keratinization and intercellular bridge. A malignant spindle cell component was not detected. Neither evidence of another primary site nor skin lesion over the tumor was found and no metastatic lesion was detected in the 5 years since the appearance of the mass.