Changing incidence of glomerular diseases in adults.

Studies performed at large metropolitan medical centers have reported an increasing incidence of idiopathic focal segmental glomerulosclerosis (FSGS) in adults. To determine whether a similar trend occurs in small urban and rural communities and to determine the role of race in these observations, we reviewed the patient records of all adults who underwent renal biopsies at our institution over the 20-year period from 1974 to 1994. The patients were grouped for analysis in 5-year intervals, 1975 to 1979, 1980 to 1984, 1985 to 1989, and 1990 to 1994, for the following diagnoses: FSGS, membranous nephropathy (MN), minimal change nephropathy (MCN), membranoproliferative glomerulonephritis (MPGN), immunoglobulin A (IgA) nephropathy, chronic glomerulonephritis, diabetic nephropathy, hypertensive nephrosclerosis, and chronic interstitial nephritis. Patients with secondary causes for these lesions were excluded. The relative frequency of FSGS increased from 13.7% during 1975 to 1979 to 25% during 1990 to 1994 (P < 0.05). The relative frequency of MN decreased from 38.3% during 1975 to 1979 to 14.5% during 1990 to 1994 (P < 0.01). There were no changes in the frequencies of MCN, MPGN, IgA nephropathy, chronic glomerulonephritis, diabetic nephropathy, hypertensive nephrosclerosis, or chronic interstitial nephritis over the 20-year period. However, there was a significant increase in the percentage of blacks with FSGS, from 0% in 1975 to 1979 to 22.6% in 1990 to 1994, and an increased percentage of Hispanics with FSGS, from 0% in 1975 to 1979 to 21.3% in 1990 to 1994 (P < 0.05). The modest increase in whites with FSGS did not reach statistical significance. The incidence of MN in blacks and whites decreased over the 20-year period. In the last 5 years, 15 patients per year had FSGS compared with 7 patients per year with MN (P < 0.05). No changes in age or sex between groups or over time accounted for these results. We conclude that FSGS is now diagnosed twice as often as MN and is the most common idiopathic glomerular disease at our hospital. Reasons for this increase include the emergence of FSGS in both Hispanics and blacks, with a modest increase of FSGS in whites. The increase in FSGS in the three most common races in our community suggests that factors other than genetic, perhaps environmental, have a role in the pathogenesis of FSGS.

Colonic disease associated with a positive assay for Clostridium difficile toxin: a retrospective study.

In this retrospective review of colonic tissue from 21 patients with a positive stool assay for Clostridium difficile toxin, four groups of patients were identified by pathologic examination. Classic pseudomembranous colitis was identified in 38% of patients in colon biopsies, resections, and at postmortem examination. One third of patients had acute colitis without specific features on colon biopsies at the time of a positive toxin assay. Effects of C. difficile toxin in patients with idiopathic inflammatory bowel disease (10%) could not be pathologically separated from activity of the underlying disease. In 19% of patients, no acute or chronic colitis or pseudomembranous colitis was noted. This report reminds gastroenterologists that C. difficile infection is associated with a range of pathologic changes similar to the well known clinical spectrum of disease.

Gastroenteropancreatic neuroendocrine tumors. A histochemical and immunohistochemical study of epithelial (keratin proteins, carcinoembryonic antigen) and neuroendocrine (neuron-specific enolase, bombesin and chromogranin) markers in foregut, midgut, and hindgut tumors.

Thirty-four gastroenteropancreatic (GEP) neuroendocrine tumors were evaluated for expression of epithelial (keratin, carcinoembryonic antigen [CEA] and neuroendocrine (neuron-specific enolase, chromogranin, bombesin) markers, and results were correlated with histologic patterns and histochemical staining. Tumors of mixed pattern (insular or trabecular with glandular areas) predominated. CEA localization corresponded to staining for mucin, with polarized apical or lumenal staining in glandular areas. Four trabecular midgut carcinoids, however, revealed diffuse cytoplasmic staining for CEA. Staining for keratin proteins was present in 68% of tumors. Bombesin immunoreactivity was demonstrated in 60% of GEP neuroendocrine tumors, indicating that bombesin positive metastatic tumors may not be predominantly of pulmonary origin, as previously suggested. Chromogranin was a sensitive marker for identifying normal gastrointestinal neuroendocrine cells that were not demonstrated by staining for neuron-specific enolase. Chromogranin was present in most neuroendocrine tumors, but was absent from three of five rectal carcinoids in keeping with the distinctive profile of hormonal and silver staining in these tumors. All GEP neuroendocrine neoplasms expressed both neuroendocrine and epithelial markers, supporting their derivation from endodermal epithelium.

Diagnosis of duodenal and ampullary epithelial neoplasms by endoscopic biopsy: a clinicopathologic and immunohistochemical study.

A series of 19 duodenal and 16 ampullary neoplasms was studied to determine their pathologic features on endoscopic biopsy, to evaluate the diagnostic accuracy of this procedure, and to assess the usefulness of immunohistochemical staining for carcinoembryonic antigen (CEA) in these neoplasms. The 11 benign neoplasms (31 per cent) were adenomas, five of which had focal hyperplastic features; the 24 malignant neoplasms (69 per cent) included ten intestinal-type carcinomas (resembling colonic carcinoma), seven anaplastic carcinomas (resembling diffuse gastric carcinoma), two adenocarcinomas in situ, and five lesions of unoriented, cytologically malignant epithelium. Malignancy was suspected endoscopically in 19 of 24 carcinomas, and the majority of the benign neoplasms were described as polyps or plaques. Resections (performed in 20 cases) demonstrated the accuracy of the biopsy diagnoses in 17 cases (85 per cent). In the three discordant cases, diagnosed by biopsy as adenoma in two cases and carcinoma in situ in one, coexistent in situ or infiltrating carcinomas were identified in the resected specimens. Carcinoembryonic antigen (20 cases) was identified mostly along glycocalyceal borders in normal and adenomatous tissues, whereas the carcinomas also showed strong cytoplasmic staining for CEA. Endoscopic biopsy is a valuable procedure in the diagnosis of duodenal and ampullary neoplasms. Correlation of the pathologic features of biopsy specimens with endoscopic appearances may result in more accurate diagnoses.