1. Introduction to Pathology

What are the subdivisions of Pathologists?

Diagnostic, experimental, molecular, and toxicologic

What are diagnostic pathologists?

Anatomic or clinical pathologists supporting clinical veterinary practice

What are experimental pathologists?

Research on pathology of infectious disease, oncology, etc

What are molecular pathologists?

Study of the molecular/genetic basis of disease

What are toxicologic pathologists?

Study changes elicited by chemical, pharmacological, and environmental agents

What are specializations in system pathology?

Neuropathology, dermatopathology, respiratory pathology, ophthalmic pathology, etc.

Define medical condition.

A broad term that includes all diseases, lesions, disorders (or even nonpathologic conditions that normally receive medical care)

Define disorder.

A disruption to regular bodily function (and structure); more value-neutral than “disease”

Define syndrome.

A combination of clinical signs associated with a specific health-related condition

Define disease.

Any condition that impairs the normal functioning of the body OR a disorder of structure of function, especially one that produces specific clinical signs

Why do we use “clinical signs” instead of symptoms?

Better description when talking about effects of disease

Define pathology.

Study of the functional, biochemical, and morphological alterations in cells, tissues, & organs that underlie disease

Define general pathology.

The study of the basic reactions of cells & tissues to abnormal stimuli that underlie all diseases

Define systemic pathology.

The study of the specific responses of specialized organs and tissues to pathologic stimuli

What are the 4 aspects of disease that form the core of pathology?

Etiology, pathogenesis, morphologic changes, and clinical significance

Define etiology.

The cause of disease (can be genetic or acquired)

Define pathogenesis.

The mechanism or sequence of events leading from initiation of cell or tissue injury to disease development

Define morphologic changes.

The structural alterations in cells or tissues/organs that are often characteristic of the disease

Define clinical significance.

The nature of the morphologic (and/or functional) changes and their distribution in tissues determine the clinical signs and course of the disease

Define lesion.

Any structural (or functional) abnormality in an organ, tissue, or cell

Define pathognomonic.

A lesion or sign that is specifically distinctive or characteristic of a disease

Define necropsy/autopsy.

Postmortem examination of the body to determine the nature of the pathological process that contributed to the death or disease

Define biopsy.

The removal and examination of tissue from the living body to establish a precise diagnosis

Define diagnosis.

A concise statement or conclusion concerning the nature, cause or name of a disease process

What is the abbreviation often used for diagnosis?

Dx

What is a differential diagnosis?

A list of disease diagnoses (rule-outs) that could account for the clinical signs or lesions in a case

What is a clinical diagnosis?

A diagnosis based on the data obtained from the case history, clinical signs, and physical examination

What is a morphologic diagnosis?

A diagnosis based on the predominant gross and/or microscopic lesion(s) in the tissues

What is an etiologic diagnosis?

A diagnosis that names the cause of the disease

What is a definitive (disease) diagnosis?

A specific diagnosis that states the name of the disease

What is the correct order for evolution of the diagnosis?

Differential → Clinical → Morphologic → Etiologic → Definitive

Why are pathologists hesitant to use the term pathognomonic?

What you are describing may not be as distinctive as you think

What should a description in gross pathology be?

Concise, grammatically correct, and anatomically precise

What should you avoid doing when describing gross pathology?

Making a description based on a preconceived diagnosis

How should you make a description?

All of these

What are the components that should be included in a description?

Tissue, number, distribution, shape, color, size, pattern, consistency, special features, other (odor, surface appearance, etc.)

Which of the following is best described with soft tissue?

Lips

Which of the following is best described with firm tissue?

Nose

Which of the following is best described as hard tissue?

Forehead

Which of the following is best described as fluctuant?

Fluid-filled

How would you describe the morphological distribution of the image?

Focal

How would you describe the morphological distribution of the image?

Multifocal

How would you describe the morphological distribution of the image?

Locally extensive

How would you describe the morphological distribution of the image?

Diffuse

What are the different levels of severity for morphological diagnosis?

Mild, moderate, marked/severe

What are the levels of duration for a morphological diagnosis?

Acute, subacute, and chronic

What are the natures of distribution for a morphological diagnosis?

Focal, multifocal, locally-extensive, diffuse

How do you name the nature of the lesion?

Inflammatory, degeneration, or neoplastic

How do you describe an inflammatory lesion?

By the type of exudate

How do you describe a degenerative lesion?

By the type of degeneration

How do you describe a neoplastic lesion?

By the type of neoplasia

Which of the following is the suffix used to describe a non-inflammatory, etiological unknown?

-opathy

Which of the following is the suffix used for non-inflammatory degeneration or necrosis?

-osis

Which of the following suffixes is used for inflammation?

-itis

What is the stain used in routine histopathology?

Hematoxylin & Eosin (H&E)

What is the stain used for lipids?

Oil-Red-O (on frozen sections)

What is the stain used for mast cell granules?

Toluidine Blue

What is the stain used for fibrin and cross sections of skeletal muscle fibers?

Phosphotungsitic acid-haematoxylin (PTAH)

What is the stain used for connective tissue and collagen?

Masson’s trichrome

What is the stain used for mucins, specifically glycosaminoglycans and proteoglycans?

Alcian Blue

What is the stain used for amyloids?

Congo Red

What is the stain used for polysaccharides and fungi?

Periodic acid-schiff (PAS)

What is the stain used for bacteria?

Gram

What is the stain used for specific bacteria?

Warthin-starry silver stain

What is the stain used for a few bacteria (especially Mycobacteria)?

Acid-fast/Ziehl-Neelsen

What is the stain used for fungi?

Gomori’s Methenamine (GMS) - silver stain

What stain is used for calcium salts?

Von Kossa

What stain is used for iron?

Peri’s Prussian blue

What stain is used for myelin?

Luxol Fast Blue (LFB)

What stain is used for melanin and argentaffin cells?

Fontana Masson’s

What stain is used for reticulin fibers?

Reticulin silver

What stain is used for elastic fibers?

Verhoeff-Van Gieson (VVG)

What is now a routine tool in veterinary pathology that is used to identify a variety of microbial and cellular antigens?

Immunohistochemistry