To define the target of chromosome 18q loss of heterozygosity, which is prevalent in endometrial carcinomas, we made a deletion map from 64 tumors. Loss of heterozygosity on 18q was found in 20 tumors. Among these, 14 tumors carried deletions at the 18q21.1 region, where the DPC4 gene is located. DPC4 transcription was disturbed in all six of the tumors with deletions at 18q21.1 examined, which sharply contrasted with the positive transcription in 12 tumors that retained heterozygosity at the 18q21.1 region. However, in the 14 tumors with the 18q21.1 deletions, the remaining allele had the wild-type sequence of the DPC4 coding region instead of somatic mutations in the DPC4 coding region. We found a one- and two-base substitutions in the DPC4 promoter in two of the six tumors that showed disturbed DPC4 transcription. Chloramphenicol acetyltransferase assays clearly demonstrated that the mutant promoters had the potential to suppress or silence DPC4 transcription, implicating the DPC4 gene in endometrial carcinoma.
Two cases of pigmented neurofibroma of the skin are reported. In case 1, the tumor was removed from the back of a 55-year-old man with no associated neurofibromatosis. In case 2, the tumor was removed from the abdominal wall of a 21-year-old woman with neurofibromatosis. Both tumors consisted of benign, short spindle cells and multiple foci of scattered melanin-laden cells. In case 1, the spindle cells were arranged in a storiform pattern, resembling features of dermatofibrosarcoma protuberans. Immunohistochemically, the spindle cells of both cases were demonstrated to be positive for S-100 protein and CD34. The melanin-laden cells stained positively for HMB-45. This report describes an additional two cases of pigmented neurofibroma that conform to the new diagnostic criteria for this disease.
Leiomyomatosis peritonealis disseminata (LPD) is a rare benign smooth muscle tumour located in the peritoneal cavity. Increased oestrogen exposure appears to be an aetiological factor for LPD. We report two cases of LPD after leiomyomectomy and assisted reproductive technology pregnancy, which can cause a high serum concentration of oestrogen. CT and MR scanning demonstrate many intraperitoneal well-demarcated nodules of varying size that mimic widespread intraperitoneal malignancy.
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