Alkaline phosphatase-positive and negative bone tumors. Ultrastructural and immunohistochemical studies of fibroblast-like tumor cells.

Bone tumors, which consist largely of fibroblast-like cells, were categorized into ALPase-positive (3 ossifying fibromas and 2 fibroblastic osteosarcomas) and negative (4 non-ossifying fibromas and 5 MFHs) groups. They were investigated as to their ultrastructure and immunophenotype using antibodies of fibroblast markers (collagen I, III, aminopeptidase M, dipeptidylpeptidase IV and factor XIIIa), classical macrophage markers (AACT and AAT) and vimentin. In the case of the ALPase-positive group, fibroblast-like cells showed short, branching rough endoplasmic reticulum with bundles of microfibrils in their cytoplasms. They were often intermingled with osteoblastic cells particularly in proximity to osteoid tissue. Furthermore, these cells expressed fibroblast markers of collagen I, aminopeptidase M, dipeptidylpeptidase IV and factor XIIIa. Fibroblast-like cells of the ALPase-negative group more or less revealed phagosomes in addition to fibroblastic features admixed with histiocyte-like cells. They expressed classical macrophage markers, but rarely fibroblast markers. The above findings indicated that derivation from different precursor cells should be proposed between the two groups and that the tumors in the ALPase-positive group might be intimately related to a certain population of the bone marrow stromal cells.

Sacral cyst managed with cyst-subarachnoid shunt: a technical case report.

STUDY DESIGN: This report describes the cyst-subarachnoid shunt, a novel surgical treatment, for sacral cysts. OBJECTIVE: To introduce a new surgical technique for sacral cysts. SUMMARY OF BACKGROUND DATA: There is no consensus on the appropriate treatment for symptomatic sacral cysts. The hydrostatic and pulsatile forces of cerebrospinal fluid are attributed to the growth of the cyst and their becoming symptomatic. METHODS: The clinical and radiologic features of a 41-year-old man with a symptomatic sacral cyst are detailed. A cyst-subarachnoid shunt was set to equalize the cerebrospinal fluid pressure between the cephalad thecal sac and the cyst. RESULTS: Immediately after surgery, the patient had no pain in his left leg and was free of pain at 2 years. Magnetic resonance imaging 1 year after surgery showed a decrease in the size of the cyst. CONCLUSION: Although this is a preliminary study, a cyst-subarachnoid shunt can be a useful alternative for symptomatic sacral cysts.

Osteosarcoma with features mimicking malignant fibrous histiocytoma.

Three osteosarcomas (OS) with features resembling malignant fibrous histiocytoma (MFH) were selected and investigated to identify any clinico-pathological similarities. In all cases there was no significant difference from conventional OS on the radiography and laboratory data. The appearance of MFH-like features within the whole tumour tissue varied from 7% to 55%. It was composed of spindle-shaped cells arranged in short irregular fascicles and a storiform pattern admixed with osteoclast-like giant cells, but devoid of neoplastic osteoid. Such spindle-shaped cells had a poorly developed rough endoplasmic reticulum and expressed a strong alkaline phosphatase activity as well as vimentin. A series of allografts to athymic mice using the MFH-like tissues also showed histologically a proliferation of plump spindle-shaped cells with a storiform pattern lacking osteoclast-like giant cells, and intensely positive for alkaline phosphatase. These findings indicate that the MFH-like features are identified as modulated OS. The constituting cells are most likely to be poorly developed with possible phenotypic alteration in the maturation stage of osteoblastic cell lineage, but different from conventional MFH of bone as regards their distinct histochemical pattern.

Knee deformities in multiple hereditary exostoses. A longitudinal radiographic study.

For a mean period of 7.8 years, the morphology of knee deformity and its annual changes in 8 patients (16 knees; mean age at the initial examination, 8.4 years) with multiple hereditary exostoses were evaluated radiographically. Knee deformity developed during the growth spurt period. Genu valgum with a femorotibial angle that decreased more than 2 standard deviations from the mean of age-matched normal children was observed in 6 of the 16 knees. In 3 of these 6 knees, recurrent dislocation of the patella was observed. Angulation of the femur varied among the knees, but the tibia showed valgus angulation in the proximal metaphysis in all knees. Thus, knee deformity in patients with multiple hereditary exostoses was primarily genu valgum caused by valgus angulation of the tibia.

Tensile properties of rat anterior cruciate ligament in collagen induced arthritis.

OBJECTIVES: To investigate the effects of collagen induced arthritis (CIA) on the tensile properties of rat anterior cruciate ligament (ACL). METHODS: The tensile strength, bone mineral density (BMD), and histology of ACL units from rats with CIA were investigated. RESULTS: The tensile strength of the ACL unit was significantly lower in the rats with CIA at 10 weeks after immunisation (ultimate failure load, 74.9% of the control; stiffness, 62.0% of the control). The major mode of failure was femoral avulsion, and the BMD was significantly lower in the rats with CIA. A histological examination of the ligament insertion in rats with CIA showed resorption of the cortical bone beneath the ACL insertion and an enlarged mineralised fibrocartilage zone. CONCLUSIONS: These findings indicate that the decrease in tensile strength of ACL units correlated with histological changes in the ligament-bone attachment, such as bone resorption beneath the ligament insertion site and an enlargement of the mineralised fibrocartilage zone.

Osteosarcoma with prominent epithelioid features.

Osteosarcoma in the metaphysis to epiphysis of the left femur of a 17-year-old male is reported. The lesion appeared osteolytic with sclerotic foci on roentgenographs, accompanied by an extensive tumor shadow in the surrounding soft tissue. While 60% of the tumor was necrotic, histological examination of the remaining viable tissue revealed that it consisted almost entirely of a sheet of epithelioid cells, separated by thin, fibrovascular septa with an alveolar-like pattern, suggestive of metastatic carcinoma. Only a few areas were characterized by malignant osteoid tissue intermingled with the above cells, showing significant positivity for bone-specific alkaline phosphatase and 5'-nucleotidase, thus permitting a diagnosis of osteosarcoma. Autopsy findings revealed that the metastatic foci were histologically similar to those of the primary tumor. Electron microscopy revealed poor development of cytoplasmic organelles, supporting possible derivation from an osteoblastic cell lineage at an early stage.

Ossifying fibromyxoid tumor of soft parts.

A histologically uncommon soft-tissue tumor of the extremities and neck of a 54-year-old male is reported. The solid, bony-hard tumors occurred at the inner region of the right thigh at 44 years of age with additional tumor formation at the posterior region of the same thigh, at the inner region of the right upper arm and at the neck during the following 10 years. All tumors were located in the deep muscle layer. The neck tumor directly invaded the fifth cervical vertebra and later the upper mediastinum. Histologically, all three tumors of the extremities contained mixed lobular growths of round-to-fusiform cells with myxoid matrix and an extensive bone formation. The tumor cells showed a small round nucleus and eosinophilic cytoplasm lacking cytoplasmic glycogen. The myxoid matrix was stained significantly by alcian blue and colloidal iron and was digested completely by pretreatment with hyaluronidase. Another major component was mature bone trabeculae showing a dense meshwork throughout the entire tumor with active bone formation toward the periphery. Positive immunostaining was obtained against antivimentin and S-100 protein antibodies. We suggest that this uncommon tumor can be tentatively distinguished as an ossifying fibromyxoid tumor of soft parts, (an entity defined by Enzinger et al.) differing from other previously described soft-tissue tumors.

Chromosomal rearrangement t(11;22) in extraskeletal Ewing's sarcoma and primitive neuroectodermal tumour analysed by fluorescence in situ hybridization using paraffin-embedded tissue.

The clonal chromosomal rearrangement t(11;22) has been reported by karyotypic analysis to be specific for Ewing's sarcoma of bone and soft tissue origin as well as primitive neuroectodermal tumour. In this report, immunohistological analysis of MIC 2 expression and fluorescence in situ hybridization (FISH) were performed using paraffin-embedded tissues. We examined t(11;22) in the nuclei isolated from two Ewing's sarcomas, four primitive neuroectodermal tumours, and three neuroblastomas, which served as negative controls by FISH with an alpha-satellite DNA probe for chromosome 11, a chromosome 22 marker probe, and whole chromosome painting probes for both chromosomes 11 and 22. Both cases of Ewing's sarcoma and the four primitive neuroectodermal tumour specimens were immunoreactive for MIC 2. Both Ewing's sarcomas and three of the four primitive neuroectodermal tumours contained the tumour-specific t(11;22), but the three neuroblastomas did not show this translocation. Based on the cytogenetic results and on the immunohistological investigation of MIC 2 expression, Ewing's sarcoma is suggested to be related closely to primitive neuroectodermal tumour. FISH is a useful aid in determining the tumour type of Ewing's sarcoma and putative related tumours.