HMGA2 expression analysis in cytological and paraffin-embedded tissue specimens of thyroid tumors by relative quantitative RT-PCR.

The distinction between benign and malignant thyroid tumors in some cytological and histological specimens remains challenging. The aim of this study was to evaluate the use of High Mobility Group A2 (HMGA2) mRNA expression to distinguish benign from malignant thyroid tumors in cytological and histological specimens. RNA samples from 170 thyroid formalin-fixed paraffin-embedded (FFPE) tissues and 226 fine needle aspiration (FNA) specimens were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The FFPE tissues included 34 follicular adenomas, 10 Hürthle cell adenomas (HA), 6 hyperplastic nodules, 4 atypical adenomas, 44 classic papillary thyroid carcinomas (PTC), 29 follicular variant of PTC, 23 follicular thyroid carcinomas, 17 Hürthle cell carcinomas (HC), and 3 anaplastic thyroid carcinomas. The FNA specimens included 55 follicular adenomas, 34 HA, 20 hyperplastic nodules, 8 Hashimoto thyroiditis, 32 PTC, 24 follicular variant of PTC, 30 follicular thyroid carcinomas, 21 HC, and 2 anaplastic thyroid carcinomas. HMGA2 mRNA levels were expressed as relative fold change after normalizing with a calibrator. HMGA2 expression in thyroid carcinomas (16.8-fold for FFPE and 18.2-fold for FNA) was significantly higher than in benign lesions (0.8-fold for FFPE and 0.8-fold for FNA). HMGA2 expression in HC was relatively low (1.8-fold for FFPE and 8.5-fold for FNA) compared with the other types of carcinomas. HMGA2 expression values of 4.5-fold and 5.9-fold were used as cutoff points for FFPE and FNA (excluding HA and HC), respectively, to separate benign and malignant thyroid tumors, with 97.5% clinical specificity and 79.8% sensitivity for FFPE, and 95.2% clinical specificity and 88.6% sensitivity for the FNA specimens. Conventional RT-PCR supported the qRT-PCR results. Detection of HMGA2 mRNA expression by qRT-PCR may be a useful tool to assist in the diagnosis of well-differentiated thyroid carcinomas. The 1-step qRT-PCR method is a sensitive, accurate, and reliable technique for gene expression analysis of thyroid tumors.

HMGA2 gene expression analysis performed on cytologic smears to distinguish benign from malignant thyroid nodules.

BACKGROUND: Up to 80% of thyroid nodules with an indeterminate diagnosis on fine-needle aspiration (FNA) (eg, "suspicious for follicular neoplasm") prove to be benign at the time of surgical resection. Ancillary tests in current use are limited in their ability to improve the preoperative detection of malignant follicular thyroid nodules. Studies using paraffin-embedded tissue have indicated that high mobility group AT-hook 2 (HMGA2) overexpression is present in a high percentage of malignant thyroid neoplasms but not in benign thyroid neoplasms. In the current study, the ability of HMGA2 overexpression analysis to preoperatively distinguish benign from malignant thyroid nodules by reverse transcriptase-polymerase chain reaction (RT-PCR) on suspicious cytologic smears was evaluated. METHODS: Patients who underwent thyroid FNA and subsequent thyroid resection from 2001 through 2007 were identified. A subset of these patients who had a cytologic diagnosis of "suspicious" underwent HMGA2 expression analysis. HMGA2 expression was detected on cells scraped from cytologic smears with 1-step, real-time quantitative RT-PCR. RESULTS: Of the 125 cases identified, RNA extraction and HMGA2 analysis were successful in 115 cases. With an HMGA2 overexpression change of 5.9-fold or greater compared with a thyroid tumor cell line as a positive cutoff, the test was found to have the following overall performance for detecting malignant nodules: sensitivity of 71%, specificity of 97%, positive predictive value of 94%, and negative predictive value of 84%. HMGA2 overexpression was found to have low sensitivity for detecting Hurthle cell carcinoma (33%). CONCLUSIONS: HMGA2 mRNA expression analysis can be performed on cytologic smears and demonstrates a high specificity and positive predictive value and relatively high sensitivity and negative predictive value for detecting malignancy in "suspicious" thyroid aspirate specimens.

Small intestinal bacterial overgrowth: histopathologic features and clinical correlates in an underrecognized entity.

CONTEXT: Small intestinal bacterial overgrowth (SIBO) is a common cause of chronic diarrhea and malabsorption. Morphologic changes associated with this condition have not, to our knowledge, been studied in detail. OBJECTIVE: To better characterize the histopathologic changes associated with SIBO by comparing the clinicopathologic features of patients with SIBO (duodenal aspirate cultures with > or =10(5) colony-forming units [CFUs]/mL) to controls with cultures found to be negative (<10(5) CFUs/mL). DESIGN: We included 67 consecutive patients with SIBO and 55 controls in the series. Each duodenal biopsy was assessed for the following features: villous to crypt ratio, intraepithelial lymphocytosis, crypt apoptoses, basal plasmacytosis, cryptitis/villitis, peptic duodenitis, erosions/ulcers, eosinophilia, and absence of goblet and Paneth cells; and correlated with clinical features and culture results. RESULTS: Decreased villous to crypt ratio (<3ratio1) was more frequent in SIBO than controls (24% versus 7%; P = .01). Duodenal biopsies from patients with SIBO were slightly less likely to be judged within reference range than were controls (52% versus 64%; P = .27). There were no significant differences in any of the other histologic features. Clinically, patients in the SIBO group were older than the age of controls (mean, 60 years versus 52 years; P = .02), and they were more likely to have one of the known predisposing factors for bacterial overgrowth (66% versus 36%; P = .002). Other clinical features, including presenting symptoms, were similar. CONCLUSIONS: Villous blunting is the only feature more common to SIBO than to controls. More than half of biopsies from SIBO patients are histologically unremarkable. Therefore, SIBO needs to be considered as a potential etiology for gastrointestinal symptoms even when duodenal biopsies are found to be normal.

Hepatocellular carcinoma metastatic to skin: diagnostic utility of antihuman hepatocyte antibody in combination with albumin in situ hybridization.

BACKGROUND: Cutaneous metastases from hepatic neoplasms are rare. Histologic features of hepatocellular carcinoma (HCC) are often poorly differentiated, hindering accurate diagnosis on routine examination by hematoxylin-eosin stain. Antihuman hepatocyte antibody is highly sensitive for HCC but can be strongly expressed in other adenocarcinomas. Albumin in situ hybridization (ISH) is highly specific and sensitive for HCC; in combination with antihuman hepatocyte antibody, it has a diagnostic sensitivity approaching 100%. To our knowledge, the combination of antihuman hepatocyte antibody and albumin ISH has not previously been examined in the context of cutaneous HCC. METHODS: We present histologic findings and results of ancillary studies for three patients with metastatic HCC. These patients had a poorly differentiated cytokeratin-positive cutaneous neoplasm. All three cases were evaluated with antihuman hepatocyte antibody and albumin ISH. RESULTS: Neoplastic cells were strongly positive for antihuman hepatocyte antibody, and ISH detected albumin messenger RNA in nearly 100% of the neoplastic cells in all three cases. CONCLUSIONS: The combination of antihuman hepatocyte antibody and albumin ISH is highly sensitive and specific for HCC metastatic to skin and is useful in the differential diagnosis of a poorly differentiated cytokeratin-positive neoplasm.