1/3. Evidence by spectral karyotyping that 8q11.2 is nonrandomly involved in lipoblastoma.We report two cases of lipoblastoma with chromosome 8-related aberrations, ie, a 92,XXYY,t(7;8Xp22;q11.2)x2 [8]/46,XY[16] in Case 1 and a 46,XY,-8,-13,add(16) (q22), mar, r [cp13]/46,XY[7] in Case 2. Using spectral karyotyping and fluorescence in situ hybridization techniques, the karyotype of Case 2 was redesignated as 46,XY, r(8), del(13)(q12), der(16)ins(16;8)(q22; q24q11.2)[cp13]/46,XY[7]. This report delineates a new chromosome rearrangement, ie, der(16)ins(16;8)(q22; q24q11.2) in lipoblastoma, and also confirms the t(7; 8)(p22;q11.2), reported only once previously, as a recurrent translocation involved in such a tumor. These findings provide valuable information for clinical molecular cytogenetic diagnosis of lipoblastoma. Furthermore, this report highlights the value of cytogenetic and molecular cytogenetic analysis in differential diagnosis of childhood adipose tissue tumors and adds to the number of lipoblastomas reported with chromosomal abnormalities at 8q11.2.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
2/3. Atypical lipomatous tumor with rare structural rearrangements involving chromosomes 8 and 12.Atypical lipomatous tumor (ALT), an intermediate malignant neoplasm of soft tissues, is characterized by the presence of supernumerary ring and giant marker chromosomes. These supernumerary chromosomes consistently contain amplified 12q-material in association with amplified segments from a variety of other chromosomes. However, a few cases of ALT with other types of chromosomal rearrangements have been reported earlier. We report on new types of structural aberrations in a case of ALT. In a pseudodiploid karyotype, there were two aberrant chromosomes, both consisting of alternating chromosome 8 and 12 sequences as shown by multicolor fluorescence in situ hybridization (FISH). The complex rearrangement was not only the result of multiple breaks and reunions of these chromosomes, but was also associated with a gain of chromosome 12 sequences. FISH analyses revealed that the number of MDM2 signals was slightly elevated (median, 5). There were three intact copies of HMGA2 and one additional copy of the 5' part of the gene. These findings are consistent with previous reports that the ALT phenotype may be associated with a low or moderate level of gene amplification, whereas truncation of HMGA2 has been observed in both ALTs and benign lipomas. The aberrations in the present case were stable, although rare cells with higher MDM2 copy numbers were detected. Whether ALTs with these types of aberrations have a lower risk of tumor progression than ALTs with the notoriously mitotically unstable ring and giant marker chromosomes remains to be investigated.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
3/3. lipoblastoma and liposarcoma in children: an analysis of 9 cases and a review of the literature.OBJECTIVES: To review the experience at a children's hospital of lipoblastoma and liposarcoma and to identify any factors that would differentiate one type of tumour from the other. DESIGN: A retrospective case series. SETTING: british columbia's Children's Hospital a tertiary-care pediatric centre. patients: All patients with a pathological diagnosis of lipoblastoma and liposarcoma recorded over 12 years. MAIN OUTCOME MEASURES: The frequency of lipoblastoma and liposarcoma, identified from biopsy specimens of pediatric adipose tumours. The clinical, pathological and cytogenetic variables between lipoblastoma and liposarcoma. RESULTS: One hundred and forty-nine adipose tumours were recorded. Seven (4.7%) were lipoblastomas and 2 (1.3%) were liposarcomas. All tumours presented as asymptomatic, slow-growing, soft-tissue masses. The children with lipoblastoma tended to be younger, but 29% were over 3 years of age. The liposarcoma patients were aged 9 and 14 years. One liposarcoma was of myxoid type and the other was a round cell variant. Karyotypes were reported for 1 lipoblastoma and 1 liposarcoma. The myxoid liposarcoma karyotype was 46,XY,t(12;16)(q13;p11), and the lipoblastoma was reported as 46,XY,der(8)?t(8q;?), mar. CONCLUSIONS: lipoblastoma is an unusual childhood neoplasm and liposarcoma is very rare in children. Both tumours may present in a similar fashion, and differentiating them histologically can be difficult. Age cannot be relied upon to accurately predict their behaviour. The tumour karyotype is very helpful in differentiating these neoplasms.- - - - - - - - - - ranking = 2keywords = karyotype (Clic here for more details about this article) |