We report a case of adenocarcinoma arising in a focus of heterotopic pancreas, occurring in the stomach of a 52-year-old man. The patient presented with gastric outlet obstruction. Radiographic studies revealed thickening of the gastric wall, but endoscopy failed to reveal a mucosal abnormality. A 50% distal gastrectomy was performed, along with vagotomy. Microscopic examination revealed extensive involvement of the muscularis propria of the distal stomach by heterotopic pancreas. The ectopic pancreas had a microscopic appearance consistent with Heinrich's class III, in which the majority of the heterotopic pancreas was characterized by cystically dilated duct structures. Occasional islets were present. Intimately associated with the cystically dilated ducts was a prominent number of small infiltrating ducts lined by columnar or cuboidal cells with enlarged hyperchromatic nuclei containing prominent nucleoli. These were consistent with a well-differentiated invasive adenocarcinoma. Despite multiple sectioning, no connection between the adenocarcinoma and the overlying gastric mucosa was seen. Adenocarcinoma arising within ectopic pancreas is a rare occurrence with fewer than 30 well-documented cases reported in the world literature to our knowledge.
Rapid processing of histopathologic material is becoming increasingly desirable to fulfill the needs of clinicians treating acutely ill patients. Traditional techniques for rapid processing of paraffin-embedded tissues require 4 to 5 hours, delaying treatment for some critically ill patients and requiring additional shifts of technologists in the laboratory. Microwave processing further shortens this time, allowing even more rapid histopathologic diagnosis. Few data exist comparing quality of microwave-processed tissue with that processed by more traditional techniques. We randomly selected 158 paired specimens from 111 patients. One member of the pair was processed routinely overnight, while the other was processed by the rapid microwave technique. The slides then were compared for quality of histologic preparation in a blinded fashion by 2 pathologists. Eight routinely processed specimens were judged as suboptimal, while 6 microwave-processed specimens were judged as suboptimal and 1 was considered unsatisfactory for evaluation. In the remaining cases, the material obtained by the 2 techniques was considered of identical quality. Microwave processing considerably shortens the preparation time for permanent histologic sections without a demonstrable decrease in section quality or "readability."
One of the most common chromosomal abnormalities in prostate cancer involves loss of 10q22-qter. Rarely, a smaller deletion, involving 10q24-q25, has been observed, suggesting the presence of a tumor suppressor gene at this site. We previously demonstrated that the MXI1 gene maps to 10q24-q25 and is mutated in some tumors with cytogenetically detectable deletions of this locus. MXI1 encodes a basic-helix-loop-helix protein that suppresses the transcriptional activity of the MYC oncoprotein by competing for the common dimerization partner, MAX, and binding to identical DNA sites. Because more than 90% of prostate tumors contain no cytogenetic abnormality of 10q, the relevance of MXI1 loss and/or mutation to the vast majority of cases remains unclear. We prospectively evaluated prostate tumors for loss of MXI1 by fluorescence in situ hybridization (FISH) and cytogenetic techniques. Twenty-one of 40 tumors (53%) demonstrated loss of a single MXI1 allele as determined by FISH. Ten cases with cytogenetically normal 10qs, but with FISH-documented deletion of MXI1, were examined at the molecular level, and eight mutations were identified, albeit at low frequency. Five of the mutant proteins were unable to bind DNA in association with MAX. We conclude that MXI1 gene loss in prostate cancer is common and most frequently involves a cytogenetically undetectable deletion.
Twenty prostate tumor specimens, obtained from radical prostatectomies, and two lymph node metastases were examined by classical and molecular cytogenetic methods. A sample from each tumor was analyzed histologically and used for touch preparations. Adjacent samples were used for preparation of single-cell suspensions before cell culture (DirFISH) and for establishing cell cultures, which were subsequently harvested for classical G-banding analysis. Fluorescence in situ hybridization (FISH) was performed on touch preparations, DirFISH, and cells obtained from tissue culture. Biotinylated pericentromeric probes for chromosomes 7 and 17, in addition to a digoxigenin-labeled X-chromosome probe, were used in a dual-color FISH assay. The results indicated that, in uncultured tumor cells, chromosome 17 was lost in 55% of specimens, chromosome 7 was gained in 16% of specimens, and 9% of specimens showed large tetraploid populations. After cell culture, 23% of specimens showed loss of chromosome 17, no specimens showed gain of chromosome 7, and no tetraploid populations were present. This study suggests that loss of chromosome 17 may play an important role in the development of prostate cancer, and that genetic changes observed after selection in vitro may not represent those in the original tumor.
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