Diagnostic pitfalls in the evaluation of fine needle aspiration cytology of the thyroid: correlation with histopathology in 260 cases.

OBJECTIVES: Fine needle aspiration cytology (FNAC) of the thyroid is a non-invasive, cost-effective screening procedure that is valuable for distinguishing neoplastic lesions from non-neoplastic nodules. The aim of this study was to determine the diagnostic accuracy of FNACs performed at our institution by correlating FNAC results with histopathological diagnoses. METHODS: Two hundred and seventy-one aspiration cytology specimens followed by thyroidectomy were included in the study, and the results of 260 adequate FNACs were compared with their histological diagnoses. RESULTS: The sensitivity and specificity of thyroid FNAC for detecting neoplasia were 92.6% and 91.6%, respectively. There were 15 (5.7%) false positives and six (2.3%) false negatives. CONCLUSIONS: The results showed that follicular cells that exhibit some of the features of papillary carcinoma could be observed in a cytology slide of Hashimoto's thyroiditis, leading to a diagnostic pitfall. In addition, cellularity and overlapping cytological criteria in hyperplasia might lead to a false diagnosis.

Evaluation of posttransplantation malignancies compared with de novo tumors.

It is uncertain whether tumors arising in transplant patients resemble ones that develop de novo in pathogenesis, morphology, and behavior. This study sought to investigate some clinical, morphological, and immunohistochemical features of several posttransplantation malignancies compared with similar de novo tumors. The study group consisted of 40 malignant tumors encountered in 1350 transplant patients (1229 kidneys, 113 livers, 8 hearts) between 1986 and 2006. Tumors with 3 or more examples were compared with randomly selected controls. These included Kaposi's sarcoma (n=14); extranodal lymphoma (n=9); squamous cell carcinoma (n=6); and nodal lymphoma (n=3). The variables that were analyzed were the localization, predisposing lesions, degree of differentiation, and host response. For lymphomas, we also determined histological subtype, origin, and Ki-67 proliferation index. Most tumors (36/40, 90%) occurred in patients with renal transplants. However, the relative frequency was higher among liver transplant cases (3.53% vs 2.92% for kidney transplants). No malignancy was seen in heart transplant cases. Squamous cell carcinomas were better differentiated (P<.05) compared with controls and they were more frequently associated with precursor lesions (P<.05). Kaposi's sarcomas involved internal organs more frequently in posttransplant patients, and the Ki-67 proliferation index was higher in posttransplantation nodal lymphomas. However, these factors were not significantly different (P>.05). Our findings suggested that certain posttransplantation malignancies display unique characteristics compared with their de novo counterparts.

Hepatocyte growth factor in patients with three different stages of chronic liver disease including hepatocellular carcinoma, cirrhosis and chronic hepatitis: an immunohistochemical study.

BACKGROUND AND AIMS: The specific role of hepatocyte growth factor in liver disease is unknown. The presence and density of this factor in patients with three different stages of liver disease were investigated, with the aim of assessing its prognostic significance. PATIENTS AND METHODS: Liver specimens from patients with chronic hepatitis (n=20), cirrhosis (n=20), hepatocellular carcinoma (n=30) and normal livers (n=20) were immunohistochemically stained to determine the presence and density of hepatocyte growth factor. RESULTS: There were significantly more hepatocyte growth factor-positive Kupffer and Ito cells in all three diseased groups than in the control group. Also, there was significantly more positive staining in chronic hepatitis specimens than in specimens from the cirrhosis, hepatocellular carcinoma and control groups (P<0.05). The hepatoma cells in 10 of the hepatocellular carcinoma cases stained positive, but none of the hepatocytes in the chronic hepatitis, cirrhosis and normal liver specimens stained. It was only possible to assess nonmalignant hepatocytes adjacent to the hepatocellular carcinoma in the four resection specimens, and no staining for hepatocyte growth factor was observed in these areas. There was no statistical association between density of hepatocyte growth factor and histological activity index in chronic hepatitis, or between density of hepatocyte growth factor and grade of hepatocellular carcinoma. CONCLUSIONS: Similar to some previous reports, this study revealed that hepatoma cells can also express this growth factor. Immunohistochemical detection of hepatocyte growth factor may prove to be a useful method of diagnosing hepatocellular carcinoma in challenging cases.

The analysis of gastrointestinal amyloidosis in 78 patients with chronic renal failure.

Systemic amyloidosis is not a single disease, but the product of a variety of diseases. Amyloid proteins are insoluble fibrils that are deposited extracellularly in many organ tissues. They stain with Congo red and appear apple green under polarized light. Definitive diagnosis and classification ofamyloidosis requires histologic examination of tissue samples. Gastrointestinal tract involvement is common, and all parts of the system can be affected Immunohistochemical studies have shown that amyloid deposited in the gastrointestinal system is most often of the AA, A kappa, or A lambda types. Another type of amyloidprotein, beta-2 microglobulin (beta2M), predominantly affects the musculoskeletal system, and is usually seen in patients who have been on long-term hemodialysis. Mixed systemic amyloidosis (beta2M and AA) is seen only rarely in these patients. In this study, we attempted to answer why this is so, and examined whether or not mixed amyloidosis is related to amyloidogenesis. We studied gastrointestinal tissues from 78 chronic renal failure patients who had systemic amyloidosis with gastrointestinal involvement. A total of 115 endoscopic samples and 1 jejunal resection specimen were analysed immunohistochemically. Immunohistochemical testing using a panel of antisera directed against two major amyloid fibril proteins (AA-Monoclonal, Dako-, and beta2M-Polyclonal, Dako-) showed that all samples contained AA amyloid, but not beta2M type protein. These findings can be explained by the patients' relatively short average duration of hemodialysis and the predominance of endoscopic biopsy samples in our study.