Histopathology

• Histopathology is the study of suffering and is a combination of histology and pathology
• It utilizes all biological sciences that study morphology, which includes structures and how diseases start
• Etiology refers to the origin of a disease with its underlying causes
• Pathogenesis is the cause of a disease and explains how the disease progresses
• Molecular and morphologic changes refer to the different structural changes that happen in tissues, cells, and organs
• Clinical manifestations are the signs and symptoms of a disease and indicate how it will progress
• Divisions of Pathology:

  1. Gross pathology:

  • Examines the entire body
  • Macroscopic changes are visible to the naked eye

  
  

  2. Microscopic pathology:

  • Focuses on the microscopic manifestations of the disease

  A. Anatomic pathology:

  • Deals with structural and compositional changes
  • Surgical pathology involves samples from living persons
  • Autopsy pathology involves samples from deceased persons

  
  

  B. Clinical Pathology includes:

  • Hematology
  • Microbiology
  • Clinical Chemistry
  • Serology/Immunology
  • Cytology and Molecular Pathology
  • Parasitology
• Necrosis refers to cell death, while apoptosis is programmed cell death or cell suicide
• Reversible changes in cells can occur in response to changes in their environment, which can be physiological or pathological
• Atrophy is a reduction in size due to a decrease in cell size and number, not cell death

  • Causes include ischemia, hypoxia, and cachexia
• Hypertrophy is an increase in size due to increased functional demand or specific hormonal stimulation
• Hyperplasia is an increase in the number of cells in an organ or tissue in response to a stimulus and can be physiologic or pathologic
• Physiologic hyperplasia includes hormonal and compensatory hyperplasia, while pathologic hyperplasia is mostly caused by excessive hormonal growth factor stimulation
• In hyperplasia, if hormonal or growth factor stimulation abates, the hyperplasia disappears
• Types of necrosis:

  • Coagulation necrosis: action of hydrolytic enzymes is blocked; occurs due to a sudden cut off of blood supply (ischemia); seen in solid organisms except the brain; necrotic material or affected organ appears like boiled material
  • Liquefactive necrosis: characterized by complete digestion of cells, affected organ appears soft and liquidy
  • Caseous necrosis: "cheese-like"; a combination of coagulative and liquefactive necrosis; observed in TUBERCULOSIS; appears greasy like cottage cheese
  • Fat necrosis: due to damage of lipolytic cells (pancreas); observed in ACUTE PANCREATITIS; appears like chalky white precipitate
  • Fibrinoid necrosis: gross changes cannot be observed; the affected area is in blood vessels
  • Gangrenous necrosis: not a form of necrosis, refers to a limb with interrupted blood supply (interruption of lower extremities)
• Ischemic injury is associated with:

  • Coagulation necrosis
• Caseous necrosis is most characteristic of:

  • Tuberculosis
• An example of hypertrophy would be:

  • Uterus during pregnancy
• Examples of hyperplasia include:

  • Glandular epithelium of pubertal breast (enlargement of the breast due to puberty) – physiologic hyperplasia
• Apoptosis has the following features except:

  • Seen in pathologic processes only – In necrosis
• The post-mortem condition of hypostasis is also known as:

  • Livor mortis – purplish discoloration of the skin; intravascular pulling of the blood in the gravitationally dependent body part
• The contraction of muscles after death is referred to as:

  • Rigor mortis
• The first step in immunohistochemistry is:

  • Treating samples with fixatives
• For frozen section, the tissue should be sent to the laboratory:

  • Fresh, unfixed
• Enzymatic digestion is the predominant event in which of the following types of necrosis:

  • Liquefactive necrosis
• Diabetic foot is an example of:

  • Wet gangrene – due to C. perfringens
• In atrophy, the cells are:

  • Shrunken cells
• For metaplasia, the following holds true:

  • It is a disorder
• Metaplasia:

  • Not a disordered growth
  • Affects only epithelial tissues
  • A reversible change
• Example of metaplasia: Columnar Epithelial to Squamous Epithelial triggered by cigarette smoking
• A tumor is termed medullary when it is almost entirely composed of:

  • Parenchymal cells
• Characteristics used for cytomorphological recognition of cancer:

  • Cytoplasmic content
  • Nuclear size
  • N:C ratio
  • Mitoses
• Statements true for Bethesda system:

  • Employed for cytologic reporting of Pap smears
  • Divides dysplasias into three grades: mild, moderate, and severe
  • All forms of dysplasias are graded into two grades: L-SIL and H-SIL
• Automated cytological technique:

  • PapNet
• Liquid-based cytology:

  • Provides uniform monolayered cell dispersion
  • Improvement of the conventional Pap smear
• Imprint cytology is most useful in lesions of the following organ:

  • Lymph nodes
• Navicular cells are:

  • Superficial squamous cells
  • Mature, largest, smallest nucleus
• Maturation index denotes:

  • Relative proportion of various cell types in a smear
• Method of choice for staining in exfoliative cytology:

  • Pap’s stain
• Components of the EA-50 stain, EXCEPT:

  • Eosin Y