Histopathological Examination - Essay Example

?Histopathological Examination of a Possible Liver Metastasis due to Recurrence of Colorectal Cancer The development of liver cancer due to the metastasis of cancerous cells from the colon has been a frequently recorded phenomenon, and this is attributed to the proximity of the two organs as well as the rich amount of blood that passes through the complex network of canaliculi within the liver itself (Khadim et al., 2011). However, the disease is asymptomatic in some patients, making it hard to detect until the late stages, and by then the patient would be subjected to invasive procedures. To prevent the rapid advancement of malignant tumour growth, tissue samples and methods of identifying cancerous liver cells are employed when masses or lesions are detected in patients that had a prior history of colorectal cancer (Goodman, 2007). In most patients being suspected of having liver cancer, certain markers that can be detected through the use of immunohistochemical methods could confirm whether the tissues from biopsy samples are either benign or malignant (Strumfa, et al., 2012). One method of obtaining tissue samples from the patient is the use of a minimally-invasive procedure called fine-needle aspiration (FNA) biopsy, along with an imaging modality such as ultrasound, MRI scan or CT scan by the laboratory technician to increase the specificity of locating the mass or lesions in the abdominal area properly (Wee, 2011). The use of imaging while conducting the biopsy ensures that the tissue samples would not be contaminated with other cell types from other organs adjacent to the liver, such as gastro-intestinal cells, aside from pinpointing the exact location of suspected malignant masses of cells (Dancygier, 2010). In some forms of malignant cancer such as haepatocellular carcinoma (HCC) certain adhesion proteins on the cancerous cells can be detected as confirmatory results using certain stains that react with the proteins’ structures, which are done through light microscopy with staining, such as the use of Hepatocyte antigen 1 (Hep Par 1), alpha-fetoprotein, carbamoyl-synthetase-1, Glypican-3 (GPC-3), epithelial cell adhesion molecule (EPCAM/MOC31), and CD10 (Ferrell & Kakar, 2011). However, the most frequently used stain in establishing whether the mass of cells or lesions detected in the liver are malignant or not is Polyclonal Carcinoembryonic antigen (pCEA), which has a high sensitivity rate of detecting malignant cells, and up to 70% of observed specimens would show the distinct staining pattern of positive results (Chu & Weiss, 2009). The brown colouration that shows the canals within the liver is due to the reaction of CEA to biliary glycoprotein on the surface of malignant cells (Clavien, 2011). Figure 1 shows the bile canaliculi pattern of an immunohistochemical staining using pCEA, which are short and disconnected, contrasting to normal liver cells having these as an extensive network. So as to prevent the rapid degradation of the tissue samples, as well as to be able to process these for further analyses such as tissue fixation or smear preparations, a small gauged needle for FNA for biopsy is used, usually of sizes 22 and smaller (Gray & Kocjan, 2010). Using this method instead of making an incision in the abdomen of the patient ensures that there would be lesser contaminants entering the samples, and the patient would not worry about excessive bleeding, under normal circumstances (Dancygier, 2010). For specimens that needed to be fixed, cell blocks can be made from the obtained tissue, but if not, the samples can be processed as a liquid specimen with a preservative such as formalin, and be later smeared on to slides or added to tissue kits complete with reagents, or stored under low temperatures (Gray & Kocjan, 2010). Rapidly working on the samples would ensure that contamination would be greatly prevented, and a faster diagnosis for the patient can be made. Figure 2 shows how a FNA biopsy is being made, using an aspirating needle. Figure 1. Typical pattern of a sample of malignant liver cells, showing the shortened, brown bile canaliculi fragments (Goodman, 2007). Figure 2. A liver biopsy being performed using a fine-needle aspirator (Dancygier, 2010). In the case of a patient suffering from liver problems, a low-risk invasive or nearly-non-invasive procedure such as FNA biopsy can be used, in conjunction with imaging modalities such as ultrasound can be used when there is a need to assess the possible recurrence of colon cancer and the metastasis of some cancer cells into the liver. After obtaining tissue samples from the patient’s liver, these can be treated using 10% neutral buffered formalin, since the use of saline would tend to break up the cells (Odze & Goldblum, 2009). Samples can then be embedded in paraffin wax to be cut into sections and subsequently stained and subjected to antibody (pCEA) application, while the remaining unused tissue samples can be kept should the tissue preparations need to be repeated (Wee, 2011). After fixing and air-drying the slides, the cells can then be observed to check for the presence or absence of distended and shortened biliary canaliculi. Positive results would indicate that the liver mass is most-likely a metastasis of cancer cells from a recurring colorectal cancer, since the pCEA test does not detect cancer cells that originated from the liver itself (Strumfa, et al., 2012). Other tests such as the use of other staining methods as well as the use of RNA markers can also be used in conjunction with the detection of CEA in liver tissues and cells, especially since the preserved samples can also be used for these techniques. Minimally-invasive methods of obtaining tissues from suspected masses of tumours such as fine-needle aspiration biopsy can decrease the risk of morbidity and mortality among patients as well as assuring that the collected cells would not be contaminated, and coupling this technique with imaging modalities also assures that the exact location of the cellular masses can be identified. In addition to this, malignant cell-detection methods with high specificities and can generate rapid results are used to make faster diagnoses, and this consequently can help doctors inform their patients much sooner as well as prescribe treatment or other courses of action for their diagnoses. Such is the rationale for choosing the methods of obtaining and processing tissue biopsy from the patient with a suspected liver metastasis. While the use of pCEA in detecting cell adhesion proteins of malignant cells has a high detection rate, care must be made in preparing the stained samples because if the stain is too strong the canalicular staining would be masked, and the cytoplasm would also become darkly pigmented as well (Chu & Weiss, 2009). In the case that the results would be disputable or if additional detection methods are needed to further solidify the possibility of the liver mass to be malignant and metastasised colorectal cancer cells, other staining methods are available and are just as reliable as the use of pCEA, or even much more sensitive in detecting cell adhesion proteins, such as alpha-fetoprotein, GPC-3 or carbamoyl synthetase-1 (Ferrell & Kakar, 2011). The use of arginase-1 can also be implemented since it also has a high sensitivity rate, however it can only be used in tandem with other methods since it can detect both malignant and benign liver masses (Strumfa, et al., 2012). Other staining methods such as the use of Hep Par 1 may not be initially implemented since these methods do not directly detect variances between benign and non-benign or malignant hepatocellular tumours (Ferrell & Kakar, 2011). Also, it is much easier to detect only certain characteristics such as the staining of the surfaces of certain parts of malignant and metastasised cells, as compared to stains which do not have any kind of cell-specific selectivity, thus the use of pCEA in detecting malignant and metastasised cells has been done for the past few decades. References Chu, P. & Weiss, L. (2009). Modern Immunohistochemistry. Cambridge: Cambridge University Press. Clavien, P. (2011). Malignant Liver Tumors: Current and Emerging Therapies. 3rd ed. Oxford: John Wiley & Sons, Inc.. Dancygier, H. (2010). Clinical Hepatology: Principles and Practice of Hepatobiliary Diseases, Volume 1. Berlin: Springer-Verlag. Ferrell, L. & Kakar, S. (2011). Liver Pathology. New York, NY: Demos Medical Publishing. Goodman, Z. D. (2007). Neoplasms of the liver. Modern Pathology, Volume 20, pp. S49-S60. Gray, W. & Kocjan, G. (2010). Diagnostic Cytopathology. 3rd ed. London: Churchill Livingstone Elsevier. Khadim, M.T., Jamal, S., Ali, Z., Akhtar, F., Atique, M., Sarfraz, T., & Ayaz, B. (2011). Diagnostic challenges and role of immunohistochemistry in metastatic liver disease. Asian Pacific Journal of Cancer Prevention, Volume 12, pp. 373-376. Odze, R. D. & Goldblum, J. R. (2009). Surgical Pathology of the Gi Tract, Liver, Biliary Tract and Pancreas. 2nd ed. Philadelphia, PA: Saunders Elsevier. Strumfa, I., Vilmanis, J., Vanags, A., Vasko, E., Sulte, D., Simtniece, Z., Abolins, A., & Gardovskis, J. (2012). Primary and metastatic tumours of the liver: expanding scope of morphological and immunohistochemical details in biopsy. [Online] Available at: http://cdn.intechopen.com/pdfs/40425/InTech-Primary_and_metastatic_tumours_of_the_liver_expanding_scope_of_morphological_and_immunohistochemical_details_in_the_biopsy.pdf [Accessed 23 January 2013]. Wee, A. (2011). Fine-Needle Aspiration Biopsy of Hepatocellular Carcinoma and Related Hepatocellular Nodular Lesions in Cirrhosis: Controversies, Challenges, and Expectations. Pathology Research International. doi: 10.4061/2011/587936. Read More