Anatomic Abstracts
Anatomic Abstracts |
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November 2004 Editors: Viability of mycobacteria in formalin-fixed lungs Viability of mycobacteria in formalin-fixed lungs It is generally accepted that the risk of contracting tuberculosis is relatively high among medical laboratory workers and pathologists. Nevertheless, it has been assumed that once tissue is fixed in formalin, the risk for transmission and subsequent infection by mycobacteria is greatly reduced if not eliminated. To test the viability of potentially infectious mycobacteria in formalin-fixed tissue, the authors cultured tissue specimens from autopsied lungs fixed in formalin for mycobacteria. Of 138 cases with histologic evidence of acid-fast bacilli, 12 grew mycobacteria, including three Mycobacterium tuberculosis isolates, suggesting that there is a risk of contracting tuberculosis from tissue that has been fixed in formalin if aerosolization or accidental inoculation occur. Gerston KF, Blumberg L, Tshabalala VA, et al. Viability of mycobacteria in formalin-fixed lungs. Hum Pathol. 2004;35:571-575. Reprints: Dr. Jill Murray, National Centre for Occupational Health, P.O. Box 4788, Johannesburg 2000, South Africa Using FNAbiopsy to distinguish benign liver from well-differentiated HCC Distinguishing well-differentiated hepatocellular carcinoma from benign hepatic lesions is challenging for pathologists using limited diagnostic material such as needle core tissue biopsy and fine-needle aspiration biopsy. The authors of this study tested a hypothesis that the fortification of liver by reticulin along single cell plates should protect benign hepatic lesions from breakdown by the force of aspiration and smearing, whereas the decreased reticulin in well-differentiated hepatocellular carcinoma (HCC) would result in finely granular fine-needle aspiration (FNA) smears. The study involved FNA biopsies of 67 cases of well-differentiated HCC and 109 cases of benign hepatic lesions, including cirrhosis (22), liver cell adenoma (eight), steatosis (seven), focal nodular hyperplasia (six), liver with cholestasis (six), and unremarkable liver sampled from nodular hepatic lesions consistent with the regenerative nodules (60). A slide with the most sample from each case by gross inspection was mixed together. Two observers blinded to the diagnoses were asked to separate the slides into two groups based on smear characteristics by gross inspection. Fragments of rigid fine-needle cores were present in all 109 cases of benign hepatic lesions but absent in 61 of 67 cases of well-differentiated HCC, which presented as finely granular smears. The difference was statistically significant (P<0.001; df=1; chi2=149.3). Using the physical characteristic of liver aspirates as the screening test for malignancy, the sensitivity was 91 percent, specificity was 100 percent, positive predictive value was 94.8 percent, and efficiency was 96.6 percent. The authors concluded that the smear characteristics of liver samples in FNA biopsy correlate to their reticulin status on histology. These physical characteristics can be used as the first clue to distinguish malignant and benign liver aspirates prior to microscopic examination. Yang GC, Yang GY, Tao LC. Distinguishing well-differentiated hepatocellular carcinoma from benign liver by the physical features of fine-needle aspirates. Mod Pathol. 2004;17:798-802. Reprints: Dr. G.C. Yang, NYU Medical Center, Cytopathology Laboratory, NB-4S-17, 462 First Ave., New York, NY 10016; grace.yang@nyu.edu Tumor karyotype predicts clinical outcome in colorectal cancer patients A study was conducted to investigate the prognostic value of the overall karyotypic features and specific chromosome aberrations in colorectal cancer. Cytogenetic features of 150 primary colorectal cancers investigated at the time of surgery were correlated with patient survival by univariate and multivariate analyses, using classical clinicopathologic parameters as covariates. In univariate analysis, in addition to tumor grade and clinical stage, structural aberrations as well as rearrangements of chromosomes 8 and 16 were significantly correlated with shorter overall survival. Karyotypic complexity, rearrangements of chromosomes 8 and 16, and loss of chromosome 4 were significantly correlated with shorter disease-free survival. In multivariate analysis, in addition to tumor grade, the type of chromosome aberrations (structural or numerical), ploidy, and loss of chromosome 18 were interpreted as independent prognostic factors in all patients. In the subset of patients with stages I and II carcinomas, none of the clinicopathologic variables could independently predict patient survival, whereas the presence of structural chromosomal aberrations was the only independent predictor of poor prognosis. In the subset of patients with stage III carcinomas, structural changes of chromosome 8 were stronger independent predictors of prognosis than was tumor grade. The authors concluded that cytogenetic tumor features are valuable predictors of prognosis in colorectal cancer patients. The tumor karyotype should therefore be taken into account in clinically managing patients with this disease, especially for patients having cancers of the early or intermediate stages of I, II, or III. Bardi G, Fenger C, Johansson B, et al. Tumor karyotype predicts clinical outcome in co lorectal cancer patients. J Clin Oncol. 2004; 22:2623-2634. Reprints: Dr. Georgia Bardi, G. Papanikolaou Research Center, Dept. of Genetics, Saint Savas Oncological Hospital of Athens, 171 Alexandras Ave., Athens 115 22, Greece; gbardi@hotmail.com Use of needle core biopsy versus fine-needle aspiration in musculoskeletal lesions Needle core biopsy has been reported to be the preferred type of biopsy for musculoskeletal tumors. Fine-needle aspiration, on the other hand, has been widely accepted for nonmusculoskeletal tumors but is used only in selected medical centers for such tumors. While fine-needle aspiration appears to have advantages over needle core biopsy with regard to simplicity and cost, diagnostic accuracy should be the most critical parameter in determining type of biopsy. However, few studies have been performed to compare the diagnostic accuracy of these two biopsy methods. This prospective study compared the diagnostic accuracy of fine-needle aspiration and needle core biopsy in musculoskeletal tumors using 50 consecutive patients who were 10 years or older. For primary musculoskeletal lesions, fine-needle aspiration achieved a diagnostic accuracy rate of 88 percent for nature of lesion, 64 percent for specific diagnosis, 78 percent for histologic grading, and 74 percent for histologic typing. Needle core biopsy achieved an accuracy rate of 93 percent for nature of lesions, 83 percent for specific diagnosis, 83 percent for histologic grading, and 90 percent for histologic typing. Both biopsy methods have a higher diagnostic accuracy rate for high-grade tumors than for low-grade or benign lesions in determining nature of lesion, specific diagnosis, and histologic grading. The authors concluded that needle core biopsy has a higher level of diagnostic accuracy than fine-needle aspiration in all aspects, including determining the nature of the tumor, establishing the histologic type and grade, and achieving a specific diagnosis. Yang YJ, Damron TA. Comparison of needle core biopsy and fine-needle aspiration for diagnostic accuracy in musculoskeletal lesions. Arch Pathol Lab Med. 2004;128: 759-764. Reprints: Dr. Yi Jun Yang, Oneida Healthcare Center, Dept. of Pathology, 321 Genesee St., Oneida, NY 13421; yyang@oneidahealthcare.org |
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