Imaging features of low-grade central osteosarcoma of the long bones and pelvis

Purpose To determine the age and gender distribution and imaging features of low-grade central osteosarcoma (LGCOS) of the long bones and pelvis and to discuss our findings in the context of lesions for which LGCOS has been mistaken.Materials and methods We reviewed 99 cases of LGCOS collected between 1919 and 2002 from our institution and pathology consultation files. Adequate imaging was available in 70 cases (36 radiographs only, 17 radiographs/CT, 12 radiographs/MRI, 2 radiographs/CT/MRI, 2 CT only, 1 MRI only, 5 bone scans).Results Patient average age was 30.1±14.2 years, with a slight female predominance. The femur and tibia were the most common long bones involved (29 and 20 each) with the majority of these tumors arising around the knee, followed by the fibula, radius, humerus and ulna (four, three, two and one case each). Flat bones were involved in six cases (three pelvis, one rib, two scapulae). Short tubular bones were involved in five cases (two metatarsal, two phalanges, one clavicle). The lesion extended to the end of the affected long bone in 22 of 59 cases. Lesions were large at presentation (mean 7.9±4.6 cm, range 2–24). Four radiographic patterns were identified: lytic with varying amounts of thick and coarse trabeculation (n=22), predominantly lytic with few thin, incomplete trabecula (n=21), densely sclerotic (n=17) and mixed lytic and sclerotic (n=10). Lesions were benign-appearing overall with focally aggressive features. CT or MRI demonstrated cortical breech or extension into the soft tissues in all cases.Conclusions LGCOS has a variable appearance on radiographs. A frequent pattern is a slow-growing large intracompartmental fibro-osseous lesion with varying amounts of septal ossification associated with focal areas of aggression. A homogeneously sclerotic pattern was also noted. Imaging with CT or MRI was helpful in every instance in our series in identifying areas of soft tissue extension or cortical disruption suggestive of a low-grade malignancy.     

Encephalopathy in Acute Leukaemia Associated with Methotrexate Therapy

Seven patients are described in whom dementia developed during treatment with methotrexate for meningeal leukaemia. The patients presented with confusion, tremor, ataxia, irritability, and somnolence. There were major epileptic fits in two cases and in one case there was progression to coma and death. Necropsy findings in the latter showed infarcted areas in the temporal and parietal lobes, with no evidence of active leukaemic disease or of viral encephalitis. The condition has not responded to radiotherapy and no positive evidence of viral encephalitis has been obtained. On the other hand, when treated with folinic and folic acid the deterioration has been arrested and there has been some improvement; thus the condition appears to be due to methotrexate. The occurrence of so many cases within the past year of a condition not previously described is probably attributable to the introduction of intensive cytotoxic therapy directed against meningeal leukaemia.     

Transient myeloproliferative disorder. In a neonate with Down syndrome. Immunophenotypic studies

This report describes the results of bone marrow leukocyte immunophenotypic studies, DNA index measurement, and chromosome analysis in a newborn with Down syndrome and transient myeloproliferative disorder. The infant's initial leukocytosis with immature cells in the peripheral blood and thrombocytopenia resolved without treatment by 6 months of age, and he was well at 2 years of age. The lack of specific reactivity between the patient's morphologically immature cells and multiple monoclonal antibodies directed against lymphoid and myeloid leukemia cells may be characteristic of this disorder. Other cases should be examined for immunophenotype to correlate the results with chromosomal analysis and to provide a basis for comparison in those who subsequently develop true acute leukemia.