We report a small, well-demarcated stromal tumor of the gallbladder in a 69-year-old woman. The tumor and associated cholelithiasis led to chronic cholecystitis symptoms. The wall of the gallbladder contained a 2.4-cm hypocellular nodule composed of bland spindle-shaped cells that were immunoreactive for vimentin, CD34, and CD117. With the latter antibody, which stains interstitial cells of Cajal (ICC), the neoplastic cells appear fusiform with elongated bipolar projections or dendritic-like cytoplasmic projections. The gallbladder wall adjacent to the tumor contained numerous CD117-positive cells in close contact with the normal smooth muscle cells, whereas two of 10 gallbladders with minimal chronic cholecystitis showed only a few CD117-positive cells. These findings provide evidence that this stromal tumor of the gallbladder shows ICC differentiation similar to some stromal tumors of the gut. The presence of numerous ICC in the uninvolved gallbladder wall suggests that this tumor might have evolved through hyperplasia of ICC.

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The clinical outcome of patients with membranoproliferative glomerulonephritis (MPGN) varies, with some patients progressing to end-stage renal disease. The aim of this retrospective study was to analyze the initial clinical signs and laboratory test results associated with an MPGN prognosis. The study cohort consisted of 47 patients with idiopathic MPGN Type I treated at the National Institute of Pediatrics, Mexico City, between 1971 and 2001. The median follow-up was 3 years. The three different outcomes of interest were death, renal failure, and nephrotic syndrome. The patients' ages ranged between 4 and 16 years. All patients had different degrees of proteinuria, hyperlipidemia, and microscopic/macroscopic hematuria, and 85.1% of them showed hypocomplementemia. Clinical outcomes varied, however, the most common was nephrotic syndrome, either alone or combined with other syndromes, which accounted for 74.5% of all cases. Fifteen patients died. Treatment with methylprednisolone improved the patient's condition, while the use of chloroquine or cyclophosphamide worsened it. Twenty-two patients had some degree of renal failure; glomerular filtration rate (GFR) levels and albumin values were negatively associated to renal failure, while treatment with methylprednisolone decreased the probability of renal failure. Nephrotic syndrome persisted in 18 patients; hemolytic complement and hemoglobin values were negatively associated with nephrotic syndrome, while macroscopic hematuria was positively associated with it. Signs that suggested a poor prognosis during diagnosis were low GFR, low albumin, low hemolytic complement, and macroscopic hematuria. Treatment with methylprednisolone seemed to improve prognosis, however, this needs to be confirmed with randomized studies.

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