Mediastinal yolk sac tumor infiltrating the heart.

BACKGROUND: As a rare tumor, yolk sac tumor is a type of neoplasm that appears like the yolk sac, extraembryonic mesenchyme, and allantois. The mediastinum is the second most frequent area after the gonadal area. CASE REPORT: We present an extremely rare case of 15 years old boy with mediastinal yolk sac tumor. The boy came with the chief complaint of swelling of the neck and face. Computed tomography scan of the chest revealed bulky mass with a cystic component that infiltrated the heart. The diagnosis of mediastinal yolk sac tumor was made after core needle biopsy. Histopathologic analysis revealed tumor mass with solid and microcystic structure and pleomorphic nucleus within the tumor cells. Laboratory finding showed elevated serum alpha-fetoprotein level reaching more than 8000 ng/ml. Echocardiography revealed a mass in the right atrium. The patient condition was rapidly deteriorated due to his vena cava superior syndrome. Unfortunately, the patient died two days after diagnosis and we did not have the chance to do the therapy. CONCLUSION: Mediastinal yolk sac tumor is a rare malignancy that requires comprehensive management. The diagnosis should be made based on histopathological findings with the addition of thoracic computer tomography scan to assess the degree of infiltration to surrounding organ. A life-threatening condition such as vena cava superior syndrome should be assessed promptly to allow for immediate treatment.

Differential expression of DNA topoisomerase II alpha and II beta genes between small cell and non-small cell lung cancer.

DNA topoisomerase II (Topo II) inhibitors are widely used in lung cancer chemotherapy, but small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) show different sensitivity to them. In this study, we examined the gene expression levels of both isoforms of Topo II (II alpha and II beta) in lung cancer specimens to investigate the differential expression between SCLC and NSCLC. The expression levels of the Topo II alpha and Topo II beta genes were assessed in 80 autopsy samples (40 primary tumors and 40 corresponding normal lung tissues) by using the reverse transcription polymerase chain reaction. We found that the expression levels of the Topo II alpha gene in tumors were significantly higher than those in normal lung tissues, and that those in SCLC were significantly higher than those in NSCLC. There were no significant differences in Topo II beta gene expression between tumors and normal lung tissues and between SCLC and NSCLC. Further-more, correlation analysis revealed that Topo II alpha expression was correlated with Topo II beta expression in both tumor and normal lung tissues. These results indicate that a difference exists in the regulation of the Topo II gene between lung tumors and normal lung tissues. Our finding of differential expression of Topo II alpha between SCLC and NSCLC also suggests that the Topo II alpha expression level is associated with sensitivity to Topo II inhibitors.

Effect of age on human peripheral blood stem cells.

We evaluated the correlation between the number of peripheral blood stem cells (PBSCs) and aging by monitoring those of CD34+ cells (PB-CD34+), colony-forming unit granulocyte macrophages (PB-CFU-GM) per 1 ml of peripheral blood in normal volunteers (n=50) including 20 males and 30 females (median age 67, range 20-90). The numbers of PB-CD34+, PB-CFU-GM were monitored by flow cytometry and methylcellulose-based colony assay, respectively. An inverse correlation between the number of PB-CD34+ with age (r=-0.33, p=0.020) was found. Furthermore, the number of PB-CFU-GM also showed an inverse correlation with age (r=-0.58, p=0.003). Based on these results, it is suggested that the number of PBSCs decrease with age.