1/4. 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 = neoplasm (Clic here for more details about this article) |
2/4. Merkel cell carcinoma arising from the subcutaneous fat of the arm with intact skin.BACKGROUND: Merkel cell carcinoma is a rare malignant neuroendocrine neoplasm characteristically arising from the dermis of sunlight-exposed skin. It rarely arises outside the skin. OBJECTIVE: We present a patient with primary Merkel cell carcinoma arising from subcutaneous fat, with no involvement of the overlying skin. We describe the clinical manifestations and magnetic resonance imaging (MRI) findings. methods: We report a 63-year-old woman with a primary lesion of Merkel cell carcinoma that arose from the subcutaneous fat layer of the left arm. The lesion presented as a subcutaneous nodule with intact overlying skin. MRI showed that the nodular lesion was located entirely in the subcutaneous fat layer, with no involvement of the dermis. Peritumoral infiltration around the lesion and enlarged lymph nodes deep to the lesion were noted. The patient received wide excision of the lesion with dissection of the regional lymph nodes and adjuvant radiotherapy and chemotherapy. RESULTS: Histopathologic examination confirmed the diagnosis of Merkel cell carcinoma with local lymphatic metastasis, and the lesion was completely located in the subcutaneous fat, with no involvement of the dermis. These findings were well correlated with MRI findings. CONCLUSION: Primary Merkel cell carcinoma may arise from the subcutaneous fat and present as an entirely subcutaneous lesion with intact skin. MRI is helpful to evaluate the local extension of the lesion and regional lymphatic metastasis.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
3/4. Recurrent maturing perineal lipoblastoma.lipoblastoma is a rare benign neoplasm of fetal adipose tissue that we see mostly in infants and young children less than 3 years of age. Most lipoblastomas occur on the extremities, trunk, head and neck, and various other organs have been described. We report a case of a recurrent perineal lipoblastoma in a 2.5-year-old boy, which showed maturation of the lipoblasts as compared to the primary tumor.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
4/4. 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 = neoplasm (Clic here for more details about this article) |