The Role of Cellular Pathology in Investigation of Lymphoma - Essay Example

? The Role of Cellular Pathology in Investigation of Lymphoma ID Number & Total Number of Words: 2,996 Introduction Lymphoma is actually a type of blood cancer cell that develops as part of the immune system. In general, lymphoma is represented by a solid cancer cells or tumors found in the lymph node. Depending on the stage and the type of cancer cell, people who are diagnosed with lymphoma can be treated with either chemotherapy, radiotherapy, or bone marrow transplant (Parham, 2005, p. 414). The presence of extranodal lymphoma is a serious health condition because it can adversely affect other organs like the brain, bones, and the skin. Similar to lyphoid leukemia, lymphomas can originate in lymphocytes which involves the blood circulation and bone marrow. According to Parham (2005, p. 414), lymphomas that originates in lymphocytes will not trigger the development of static tumors. The main function of lymphocytes is to detect not only the presence of infectious organisms or pathogens like virus and bacteria which may invade the human body or the presence of any forms of abnormal cells such as cells that are infected by virus or bacteria and the presence of cancer cells (Martini et al., 2007, p. 578). When this happen, the lymphocytes work to destroy either the infectious organism or response to the presence of abnormal cells. Specfically the B lymphocytes function by producing protein antibodies that will circulate around the lymph and blood to carry out invasive pathogens and abnormal cells in the body. On the other hand, the T lymphocytes is responsible in killing the pathogens that are transported by the B lymphocytes from the affected area (Bender et al., 1997, p. 164). Lymphoma happens when the B or T cells uncontrollably grow and multiply to form a cancerous mass or tumors (Bertrand et al., 2010; Connors, 2009). Even though lymphoma is a type of cancer that is cureable, between 40% to 70% of the affected person may not survive (Lymphoma Research Foundation, 2012). To improve the treatment given to patients with lymphoma, it is necessary on the part of the healthcare professionals such as the cytopathologists or cytotechnologists to closely examine and have a better understanding with regards to the role of cellular pathology in investigating incidence of lymphoma. As part of going through the main discussion, it is necessary to identify and discuss the types, subtypes and classification of lymphoma. Eventually, the importance of cellular pathology with regards to investigating lymphoma will be tackled in details followed by discussing the common laboratory tests used in investigating cases of lymphoma. Types, Subtypes, and Classification of Lymphoma Classified under hematological neoplasm, lymphomas may develop under different classification, form, and type. In 1832, the first study on lymphoma was published by Thomas Hodgkin. For this reason, the first type of lymphoma is known as the Hodgkin’s lymphoma (Hellman and Mauch, 1999, p. 5; Kuppers and Rajewsky, 1998). The other type of lymphoma is known as the non-Hodgkin’s lymphoma (Kramer et al., 2012; Bertrand et al., 2010; Swerdlow et al., 2008). The Hodgkin’s and non-Hodgkin’s lymphoma develop in almost the same way except for the fact that the tissue cells that is affected by the Hodgkin’s lymphoma is composed of a single type of cell known as the Reed Sternberg cell (Kuppers and Rajewsky, 1998). In most cases, the Hodgkin’s lymphoma can be found not only in the lymph nodes but also in other organs like the bone, bone marrow, liver, lungs, and spleen (Connors, 2009). Examples of Hodgkin lymphoma includes: nodular lymphocyte predominant Hodgkin lymphoma, and the four (4) subtypes of classic Hodgkin lymphoma (CHL) which includes the mixed cellularity CHL, the nodular sclerosis CHL, lymphocyte-rich CHL, and the lymphocyte-depleted CHL (Pileri et al., 2002). Unlike the Hodgkin’s lymphoma, a wide-range of cancer cells fall under the type of non-Hodgkin’s lymphoma. For this reason, the non-Hodgkin’s lymphoma has a couple of subtypes known as the T-cell lymphomas and B-cell lymphomas (Bakshi and Maghfoor, 2012; Connors, 2009; Jaffe, 2009; Carbone, Gloghini, & Dotti, 2008; Tan, Chiu and Koay, 2007). According to Carbone, Gloghini and Dotti (2008), most of the mature T-cell (natural killer) lymphoproliferative disoders are very much associated with the Epstein-Barr virus (EBV) combined with the subset of aangioimmunoblastic T-cell lymphoma, the peripheral T-cell lymphoma, and other types of rare lymphomas. (See Table I – Summary of Non-Hodgkin Lymphoma Subtypes below) Table I – Summary of Non-Hodgkin Lymphoma Subtypes T-Cell Lymphomas B-Cell Lymphomas Adult T-cell leukemia/lymphoma; Aggressive NK cell leukemia; Angioimmunoblastic T-cell lymphoma; Anaplastic large cell lymphoma, ALK+; Anaplastic large cell lymphoma, ALK-; Cutaneous T-cell lymphoma; EBV+ T-cell LPD Enteropathy type T-cell lymphoma; Extranodal natural killer / T-cell lymphoma; Hepatosplenic T-cell lymphoma; Mycosis fungoides; Peripheral T-cell lymphoma; Primary cutaneous CD30+ T-cell LPD; Primary cutaneous peripheral T-cell lymphoma (rare subtype); Sezary syndrome; Subcutaneous panniculitis T-cell lymphoma; and T-cell large granular lymphocytic leukemia; and T-cell prolymphocytic leukemia. ALK+LBCL B-cell prolymphocytic leukemia; Burkitt lymphoma Chronic lymphocytic leukemia / Small lymphocytic lymphoma (CLL/SLL); Diffuse Large B-cell Lymphoma (DLBCL); EBV+ DLBCL Extranodal marginal zone B-cell lymphomas such as the mucosa-associated lymphoid tissue (MALT) lymphomas; Follicular lymphoma; Hairy cell leukemia; Heavy chain diseases Lymphomatoid granulomatosis; Lymphoplasmocytic lymphoma; Intravascular LBCL Mantle cell lymphoma; Nodal marginal zone B-cell lymphona; Primary central nervous system (CNS) DLBCL; Plasmablastic lymphoma; Primary cutaneous FCL; Primary effusion lymphoma; Primary mediastinal B-cell lymphoma; Splenic marginal zone B-cell lymphoma; Splenic marginal zone B-cell unclassifiable; T/histiocyte rich LBCL among others. Source: Bakshi and Maghfoor, 2012; Connors, 2009; Jaffe, 2009; Tan, Chiu and Koay, 2007 In 2008, the World Health Organization officially revised its 2001 version of lymphoma types and classification. Other than publicly introducing several new entities and variants, some of the globally known lymphoma catergorie were redefined in the World Health Organization’s 2008 update. Based on the article review that was written by Bakshi and Maghfoor (2012), the World Health Organization (2008) listed almost eighty (80) different forms of lymphoma under five (5) major groups known as the Diffuse Large B-cell Lymphoma (DLBCL), the T-cell/histiocyte-rich large B-cell lymphoma (T/HRLBCL), the Low-grade B-cell Lymphoma, the Primary Mediastinal large B-cell lymphoma (MED LBCL), and the Classical Hodgkin Lymphoma (Jaffe, 2009; Swerdlow et al., 2008; Tan, Chiu and Koay, 2007). Aside from providing a more accurate definition with regards to the anaplastic large cell lymphoma, angioimmunoblastic T-cell lymphoma, enteropathy-associated T-cell lymphoma, and subcutaneous panniculitis-like T-cell lymphoma, the World Health Organization (2008) introduced new variants under the primary cutaneous T-cell lymphomas (Jaffe, 2009). Importance of Cellular Pathology (Cytopathology) in Investigating Cases of Lymphoma As a branch of pathology, cellular pathology or cytopathology aims to study the diagnoses of specific diease at a cellular level (Kirkpatrick et al., 1989, p. 324). In line with this, several studies pointed out that each type of lymphoma has its own unique set of histopathology and immunophenotype (El-Sayed et al., 2008; Dunphy, 2000; Biesemier et al., 1994). Therefore, by studying the cellular pathology of lymphoma, the cytopathologists will be able to easily determine the type of lymphoma that the patient is suffering. To be able to detect the presence of cancer cells at an early stage, cytologic / FNB smear tests or a fine-needle aspiration can be done to obtain samples of infected cells, serous fluids, or other specimen which can examined using a microscope or through the process of cytocentrifugation (Collony et al., 2000; Orell and Philips, 1997, p. 25). In most cases, superficial biopsy can be used to monitor the progress or status of a benign tumor (Storm and Seykora, 2002). Depending on the cytopathologic test results, patients who are diagnosed with malignant tumor are often encouraged to receive either immediate chemotherapy or ration therapy (or both) or to undergo a surgical removal of the tumor cells (Bertrand et al., 2010; Carbone, Gloghini and Dotti, 2008; Storm and Seykora, 2002). Specifically the main responsibility of cytologists is to test and determine whether or not precancerous or cancerous cells are present within the cellular samples being tested (Collony et al., 2000). Using this particular diagnostic intervention, the cytopathologists will be able to determine whether or not the sample cells they are testing is showing signs of unusual cellular growth and unusual division or metabolism of cells. Laboratory Investigation and Examples The clinical term “cytology” is referring to the study of cells. In line with this, several studies strongly suggest that the process of studying the cells’ histopathology, immunohistochemistry, and immunophenotype, the cytopathologists will be able to easily determine the type of lymphoma that the patient is suffering (El-Sayed et al., 2008; Dunphy, 2000; Biesemier et al., 1994). Given the fact that each type of lymphoma has its own unique qualities in terms of the histopathology and immunophenotype, laboratory intervention is often used to explore and examine the characteristics of each type of lymphoma. As part of the laboratory test procedure, cytologists will first have to test the patients’ blood count including the differential blood count. For example, in case of testing the cell samples for signs of T-cell prolymphacytic leukemia, cytologists should take note the that white blood cells (WBC) in T-PLL is usually more than 100 x 109L and that patients who are suffering from concominant anemia or thrombocytopenia can have a negative HTLV-1 (Erber, 2010, p. 193). After testing the blood count, the next laboratory step is the flow cytometric immunophenotyping of the blood (Skoog and Tani, 2009, p. 3). At this stage, cytologists may look for T-cell phenotype which includes CD3+, CD4+, CD4, CD8 dual positivity, and other T-cell markers such as the CD5, and CD7 (Erber, 2010, p. 193). CD2 and CD3 are possible marker of T-cells but are usually considered as weak. Other immature markers include the TdT, CD1a, and CD34. In most cases, the morphology of T-PLL cells are usually small to medium in terms of size with matching round or uneven shape in the nuclear contours. The morphology of T-PLL cells can also be characterized by having a set of mature chromatin, scane, an unclear nucleoli known as the small cell variant, and agranular cytoplasm that has blebbing (Erber, 2010, p. 193). According to Skoog and Tani (2009, p. 3), the FNA of lymph nodes can either be used as a primary or a follow-up diagnosis with immunophenotyping of lymphoma. In the study of cellular pathology, biopsy is often performed by the cytologists in order to collect the needed samples or specimen for the laboratory testing (Norton, Taylor and Nunwa, 2008, p. 231). It means that after the blood count and the flow cytometric immunophenotyping of the blood, the next step is to perform a lymph node biopsy. There are several ways in which lymph node biopsy can be done. The first technique is the excisional biopsy. According to Ranchod (2010, p. 255), excisional biopsy is often performed in case the lymph node is still intact. Through excisional biopsy, cyotologists can easily remove the entire affected lymph node. Before the sample can be delivered to the laboratory, the specimen will have to be immersed in a small volume of saline solution especially in cases wherein there will be some delay in the transferring of the specimen. On the other hand, incisional biopsy can be done on larger lymph nodes like the large blood vessels or nerves because this kind of sample is not easy to remove safely (Ranchod, 2010, pp. 254 – 255). The fine needle aspiration biopsy (FNAB) is less invasive as compared to both the incisional and excisional biopsies whereas the needle core biopsy is a preferred technique each time the cytologists need to evaluate “deep-seated lymph nodes in the abdomen or retroperitoneum” (Ranchod, 2010, p. 254). In most cases, the cytomorphologic and immunophenotype that will be taken from the first diagnosis may not be enough as a basis for detecting the type of leukemia because of the fact that the immunophenotype of certain leukemia can also be present in other types of leukemia. For this reason, a lymph node biopsy is often used to confirm or verify the accuracy of the first diagnosis (Loachim and Medeiros, 2009, p. 27). In line with this, the lymph node FNAB technique is commonly performed to allow the cytologists to obtain samples from the patients which will be needed in developing a well-established diagnosis for lymphoma (Loachim and Medeiros, 2009, p. 27). The next step is the preparation and the actual examination of the imprint of fresh sliced lymph node. To preserve the imprint of fresh sliced lymph node, it is necessary to dry the imprint on air and stained it using the Giemsa fluid for 2 to 14 hours or “fixed in a mixture of 10% formalin and 100% ethanol (50:50 by volume)” before staining it with hematoxylin and eosin (H&E) protocol for the frozen sections (Leong, 2011, pp. 11 – 12). This particular laboratory preparation is necessary for the future study of cell cytology which includes the histochemical and immunohistochemical (Leong, 2011, p. 12). In preparation for the imprints, the fresh tissue should be placed on the glass slides and fixed it with 80% alcohol, Giemsa or Wright or the standard H&E stain so that the cytologists will be able to distinguish the unique cell characteristics of the sample (Vigorita, Ghelman and Mintz, 2008, p. 492). With regards to the actual examination of the imprint of fresh sliced lymph node, cytologists are expected to conduct immunohistochemical, morphometric, and DNA ploidy analysis based on the imprints (Loachim and Medeiros, 2009, p. 21). Formalin fixation and snap freezing of tissue are two ways of preserving the tissue or cell samples for molecular analysis. Specifically the use of snap freezing technique is good in terms of the RNA quality whereas the formalin fixation is good in terms of preserving the morphology of the samples (Bosch and Felipo, 2003, p. 22). As part of the immunocytochemistry procedure, the glytaraldehyde is commonly used for the fixation of the fresh tissue samples. This procedure is necessary for the purpose of electron microscopy testing. After the fixation of the fresh samples, cytologists will be able to easily detect the cellular characteristics of the cell samples using an electron microscope. Other than the standard H&E section, a routine formalin fixation is necessary to allow the cytologists to trace and study unusual characteristics in tumour (Vigorita, Ghelman and Mintz, 2008, p. 492). A single cell suspension is a process wherein the tissue sample is broken up to form single cells that floats within a given solution. To make a single cell suspension, it is necessary for the cytologists to clean the sample tissue with blood stain using 5 to 10 ml of HBSS. Using a sterile forcep, cytologists should transfer the 1 to 2 mm tumour cell or tissue sample onto a glass dish followed by adding 5 to 10 ml RPMI 1640 before allowing the large fragments to settle at the bottom after a few minutes (Langdon, 2004, p. 103). The next step is the process of identifying the immunophenotype of lymphoma. Basically, the clinical term “immunophenotyping” is referring to the process of analyzing the parameters of lymphoma (i.e. antigen expression) using immunologic method (Sun, 2008, p. 45). This makes it possible for cytologists not only to determine whether or not the tumour is malignant or benign but also to determine the sub-classification of each type of lymphoma (i.e. B-cell lymphoma or T-cell lymphoma etc.). In other words, the antibodies in each cell sample can be used to refine the clinical diagnoses of lymphoma. For example, CD23 is one of the antibodies that clearly distinguish a small cell lymphoma from the mantle cell lymphoma (Sun, 2008, p. 45). Among the few methods of molecular technique which can be used in immunophenotyping includes the polymerase chain reaction-based assays (PCR) and the fluorescence in situ hybridization (FISH) method. Specifically the PCR-based assays can be used to assess whether or not the specific configuration of the Ig and T-cell receptor genes have a false-negative result (Loachim and Medeiros, 2009, p. 27). On the other hand, the FISH method is commonly used to detect chromosomal translocations or abnormalities in the number of chromosome. For example, abnormality in trisomy 3 is a common indicator of MALT lymphoma (Loachim and Medeiros, 2009, p. 28). For example, the histopathology of a precursor T-cell lymphoma is often characterized not only by a condensed chromatin but also some form of irregular nuclear contours together with some small nucleoli and some scant cytoplasm that has no granules (Vega et al., 2001). Among the common immunophenotype of a precursor T-cell lymphoma includes the CD2, CD7, and terminal deoxynucleotidyl transferase (TdT) whereas subtypes like LYL1+, HOX11+, TAL1+, and MLL+ pre T ALL/LBL.HOX11 can serve as a prognosis for an adult precursor T-cell lymphoma (Han and Bueso-Ramos, 2007). The histopathology of a Burkitt’s lymphoma is characterized by having a round-shape lymphoid cells that has multiple nucleoli with a starry-sky manifestation (Ferry, 2006). In most cases, the common immunophenotype of a Burkitt’s lymphoma includes the pan-B cell antigens, CD10 and the clonal surface immunoglobulins (SIgs) (Kelemen et al., 2010). Conclusion It is clear that the study of cellular pathology or cytopathology is important in terms of detecting the early stage of lymphoma (Pileri et al., 2002; Collony et al., 2000). Through early diagnoses, the patients will have a higher chance of having their lymphoma treated and cured as they receive the recommended treatments. A series of laboratory testing is necessary to ensure that cytologists will be able to identify not only the immunophenotype of lymphoma but also the antigens and the histopathology behind each type of lymphoma. Since there are some antigens and phonotype that are overlapping with one another, the process of gathering signs of differential in the blood count and the flow cytometric immunophenotyping of the blood is not enough to provide an accurate diagnosis result. 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