40 Questions
What is the definition of a neoplasm?
An abnormal tissue proliferation that exceeds that of adjacent normal tissue
What is the term used interchangeably with a tumor?
Neoplasm
What is the study of neoplasms called?
Oncology
What is the term for the entire population of cells within a tumor?
Clone
What is the role of the stroma in a tumor?
It carries the blood supply and provides support for parenchymal cells
What is the term for a benign tumor of fibroblasts?
Fibroma
What is the term for the cell that has sustained the initial genetic changes in a tumor?
Tumor-initiating cell (T-IC)
What is the characteristic of a neoplasm that distinguishes it from normal tissue?
It is independent of physiologic growth stimuli and inhibitors
What is the primary factor that distinguishes between benign and malignant tumors?
Degree of differentiation
What is the term used to describe the extent to which neoplasms resemble their parenchymal cells of origin?
Differentiation
What is the characteristic feature of anaplastic cells?
Abnormal nuclear morphology
What is the term used to describe the spectrum of neoplasm differentiation?
Differentiation spectrum
Which of the following is an example of a well-differentiated neoplasm?
Thyroid follicular carcinoma
What is the characteristic feature of poorly differentiated neoplasms?
Barely resemble normal cells of origin
What is the term used to describe the variations in the size and shape of neoplastic cells and their nuclei?
Pleomorphism
How are malignant neoplasms generally divided based on their degree of differentiation?
Into 4 categories
What is the term applied to a benign epithelial neoplasm that forms microscopically recognizable glandular structures?
Adenoma
What type of tumor arises from or differentiates towards mesenchymal cells?
Sarcoma
What is the term for a benign neoplasm that forms a macroscopically visible projection above a mucosal surface?
Polyp
What is the term for a malignant neoplasm that arises from or differentiates towards epithelial cells derived from any one of the three germ layers?
Carcinoma
What is the term for a carcinoma with a microscopic glandular growth pattern?
Adenocarcinoma
What type of malignant tumor is composed of undifferentiated cells that have no enough microscopic criteria to indicate their site of origin or differentiation?
Undifferentiated (anaplastic) malignant tumor
What is the term for a benign epithelial neoplasm producing microscopically or macroscopically visible finger-like projections from epithelial surfaces?
Papilloma
What is the term for the deep bluish staining of nuclei due to abnormally high content of DNA?
Hyperchromatism
What is the normal nuclear-cytoplasmic ratio in cells?
1:4 or 1:6
What is the term for a benign neoplasm that forms large cystic space (or spaces)?
Cystadenoma
What is the term for the aberrant distribution of chromatin in malignant nuclei?
Chromatin clumping
What is the significance of atypical mitotic figures in malignant cells?
They are a morphologic feature of malignancy
What is the term for the disorganized growth pattern of malignant cells?
Loss of polarity
What is the term for the large, abnormally shaped cells seen in malignant tumors?
Cancer giant cells
What is the term for the variation in nuclear shape seen in malignant cells?
Pleomorphism
What is the significance of frequent mitoses in malignant cells?
It indicates high proliferative activity
What is the characteristic of a mixed tumor?
The tumor cells undergo divergent differentiation, and are of monoclonal origin
What is the best example of a mixed tumor?
Pleomorphic adenoma
What is the characteristic of a teratoma?
It contains cells or tissues derived from more than one germ cell layer
What is the alternative name of cystic teratomas?
Dermoid cysts
What is the correct name for a carcinoma of melanocytes?
Melanocarcinoma
What is the characteristic of a hamartoma?
A mass of disorganized tissue indigenous to the particular site
What is the characteristic of a choristoma?
A congenital anomaly consisting of a heterotopic nest of cells
What are the three fundamental features by which most benign and malignant tumors can be distinguished?
Differentiation and anaplasia, local invasion, and metastasis
Study Notes
Neoplasia
- Neoplasia is a crucial topic in pathology because neoplasms are common and serious diseases.
- A neoplasm is an abnormal tissue proliferation that exceeds that of adjacent normal tissue and continues even after removing the causative agent.
- The persistence of proliferation is the result of heritable genetic changes in the constituent cells, making the neoplasm autonomous and independent of physiologic growth stimuli and inhibitors.
Oncology and Neoplasm
- Oncology is the study of neoplasms (Greek oncos = tumor).
- A neoplasm originates from a single cell, referred to as a stem cell or tumor-initiating cell (T-IC), which has sustained the initial genetic changes (mutations).
- The entire population of cells within any tumor originates from this single cell, forming a clone of cells; hence, tumors are said to be clonal.
Components of a Tumor
- Parenchyma: made up of neoplastic cells, determines the biologic behavior of the tumor, and is the basis for naming the tumor.
- Stroma: made up of connective tissue and blood vessels, vital to the neoplastic cells, carrying the blood supply and providing support for parenchymal cells.
Nomenclature of Neoplasms
- Benign tumors: named by attaching the suffix -oma to the cell of origin (e.g., fibroma, chondroma, osteoma).
- Malignant tumors: follow similar nomenclature rules, with certain additions (e.g., sarcomas, carcinomas, lymphomas, leukemias).
- Special types of malignant tumors: undifferentiated (anaplastic) malignant tumor, mixed tumors, Teratoma, and Hamartoma.
Characteristics of Benign and Malignant Neoplasms
- Three fundamental features to distinguish benign and malignant tumors: differentiation and anaplasia, local invasion, and metastasis.
- Rapid growth is not a reliable discriminator between benign and malignant tumors.
Differentiation and Anaplasia
- Differentiation refers to the extent to which neoplasms resemble their parenchymal cells of origin, both morphologically and functionally; lack of differentiation is called anaplasia.
- The degree of tumor differentiation is represented by a spectrum, dividing neoplasms into very well differentiated, well differentiated, moderately differentiated, poorly differentiated, and undifferentiated (anaplastic).
Morphologic Features of Undifferentiated (Anaplastic) Malignant Cells
- Pleomorphism: variations in the size and shape of the neoplastic cells and their nuclei.
- Abnormal nuclear morphology: hyperchromatism, high nuclear-cytoplasmic ratio, variations in nuclear shape, and abnormal chromatin clumping and distribution.
- Abnormal mitoses: large number of mitoses, reflecting high proliferative activity, and atypical mitotic figures (e.g., tripolar, quadripolar, or multipolar mitoses).
- Loss of polarity: disturbed orientation of the cells, growing in disorganized fashion.
- Formation of tumor giant cells: abnormally large cells with pleomorphic nuclei.
Learn about neoplasia, a crucial topic in pathology, including the definition, characteristics, and study of abnormal tissue growth.
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