Neoplasms Classification PDF

Classifications of neoplasms All tumors, benign and malignant, have two basic components that interact one with the other: Parenchyma:  made up of transformed or neoplastic cells,  determines its biologic behavior,  from which the tumor derives its name Stroma:  non-neopl...

Classifications of neoplasms All tumors, benign and malignant, have two basic components that interact one with the other: Parenchyma:  made up of transformed or neoplastic cells,  determines its biologic behavior,  from which the tumor derives its name Stroma:  non-neoplastic supporting cells,  connective tissue, host-derived blood vessels, and host-derived inflammatory cells. Classification of cells by their differentiation potential o Totipotential cell o Pluripotential cell o Differentiated cell o Permanent cell Neoplasms of Totipotential cells  Normally only zygote has truly totipotent cells that can produce all of the differentiated cells in an organism.  Primordial Germ Cells can be reprogrammed (mostly by demethylation, to remove epigenetic imprints)  Malignant but slower growth  May metastasize retroperitoneal  Pregnancy type markers will be produced: Placental alkaline phosphate, possible hCG,  Germ cell accounts for 95% of testicular tumors but only 90%)  Benign, cystic (dermoid cyst)  Mature tissue from all germ layers present (skin, muscle, bone, hair) o Immature (rare)  Malignant  Minimally differentiated o In fetus and newborns: sacrococygeal and cervical o Ovarian: 25% of ovarian tumors o Testicular: almost 50% of testicular tumors o Concern for pluripotent stem cells thet could lead to teratoma formation but are intsnsly studied in tissue engineering Tumors of primordial cells  These are tumors of the primitive organ anlage cells = primordial cells = blast cells  These are all highly malignant  These manifest clinically under the age of 5 years  Many types of blastoma have been linked to a mutation in tumor suppressor genes Tumors of differentiated cells  Tumors of epithelial origin o Benign- Papilloma, polyp or adenoma o Malignant it is a carcinoma o More than 80% of the cancer related deaths o e.g.: lung, liver, GI, skin, breast, pancreas, ovary, gallbladder, urinary bladder.  Tumors of mesodermal origin o Benign- Take the cell type and add -oma o Malignant- Take the cell type and add sarcoma  Hematopoetic origin o Leukemia - Free, non-aggregated tumors o Lymphomas – aggregated tumors of lymphoid cells (B and T cells) in lymph nodes o Plasmocytoma & Multiple myeloma: of plasma cells (in bone marrow)  "punched-out" resorptive lesions  Neuroectodermal o Glioblastoma multiforme: multiple distinct neuroectodermal cell types with nuclei of various sizes Dr M Hossu Notes 147  Exceptions to naming of neoplasms  Tumors that are benign but sound malignant o Osteoblastoma and chondroblastoma  Tumors that are malignant but sound benign o Lymphoma, glioma, melanoma, plasmacytoma Eponymous neoplasms Ewing’s sarcoma- This is a tumor of bone that has origin most probably in neural crest instead of mesodermal cells. Hodgkin’s lymphoma- this is a malignant tumor of lymphocytes in the lymph node, but it is different to other types of lymphoma. In particular it is probably of T cell origin, not B cells, and the typical cell type here is the Reed-Sternberg cell not the lymphocyte. It is also different in that it tends to occur in young individuals (particularly males), not in the elderly and it is not associated with immunodeficiency states. Brenner tumor- This is a tumor of the stroma of the ovary, not of the germ cells themselves or the germinal epithelium. Burkitt’s lymphoma- This is a B cell type of lymphoma, but is found not in the elderly but in children. It is associated with both Epstein-Barr virus infection and the presence of chronic malaria. The abnormal lymphocytes are in the bones of the jaw and not in lymph nodes. The characteristic histologic appearance is described as the “Star in the Sky” or “Starry Sky” appearance. Kaposi’s sarcoma- This is an angiosarcoma of vessels in the dermis that is associated particularly with HIV infection, but it is due to a concomitant infection with HHV-8. Wilm’s tumor- AKA nephroblastoma. It is the malignant tumor of the kidney that is seen in young children and has its origin in embryology. Grawitz’s tumor –AKA hypernephroma. It is the malignant tumor of the kidney that is seen particulary in older individuals and can be associated with the presence of carcinogens such as from cigarette smoking. Hürthle cell tumor- tumor of the stroma of the thyroid gland Krukenberg’s tumor- This is a secondary carcinoma of the ovary that came from a primary gastric carcinoma by transcoelomic spread. The appearance of the cells is not of any of the tumors that are seen to develop from cells in the ovary, but instead are adenocarcinoma cells that have a typical appearance of a gastric carcinoma. Dr M Hossu Notes 148