Definitions
What is a necropsy?
Postmortem examination of an animal
What is the ratio for fixing tissue samples?
10:1 formalin to tissue
What is an incidental lesion?
Abnormal finding, but not causing the significant problem in the animal
Describe the word pedunculated?
Having a stalk or peduncle
What does FNA stand for?
What is difference between pathogenesis and pathophysiology?
Pathogenesis - how the disease is acquired and how it inflicts injury on organs and tissues
Pathophysiology - what the lesions (abnormalities) do to function of the body
What is a biopsy and how are samples often examined by a pathologist?
Chunks of tissue taken from a live animal and samples are looked at with light microscopy
Define the difference between an acute vs chronic lesion?
Acute - recent onset or short duration
Chronic - been going on awhile
A lesion that grows inward protruding into the skin is called?
Endophytic
Having a sharp knife reduces the amount of force needed to cut through tissue and hopefully reduce bodily harm
What is a PCR and what type of material is being tested in a sample?
PCR - polymerase chain reaction
Identifying a specific pathogen via a particular DNA sequence (genetic material)
What are the 2 essential functions fixation of tissues provides?
Cessation of all normal life functions in the tissue
Stabilization and preservation of the structure of the tissue
Define the term pathognomonic and give an example?
Pathognomonic - characteristic of only one known disease/condition
Ex: linear foreign body in the intestines known as plication
Describe the difference between "expansile" and "infiltrative" of a lesion in a tissue?
Expansile - causing compression of surrounding tissue (Ex: lipoma)
Infiltrative - spreading into surrounding tissue
What special accommodation does the brain have when being fixed in formalin?
The brain can be placed into formalin whole, but just make sure it fits in a large enough container
Define the term putrefaction and name 1-2 observations that you would observe in the animal?
Putrefaction - breakdown of cells by overgrowth of cadaver bacteria
Examples: bloat, gas distention and bubbles in tissue, pseudomelanosis (blue to green discoloration of tissues)
FNA's are similar to biopsies and are often the primary alternative since they require low invasiveness to collect a sample. What are the 2 main drawbacks to FNA's that were discussed in class?
Very small samples
No tissue architecture (only see present cell types) and have little context in terms of tissue organization
What are the 4 different distribution patterns we learned to describe lesions and briefly describe how each type would present?
Focal - single lesion
Multifocal - multiple identifiable lesions
Locally extensive - large region of the organ affected by lesion
Diffuse - evenly distributed (cannot isolate individual lesion)
What is the difference between a "cystic" and "encapsulated" lesion?
Cystic - forming one more more cavities (generally contains fluid or other material)
Encapsulated - lesion is surrounded by an outer rim of different tissue
Name 5 different tools that you would need to perform a necropsy?
Sharp knife, scalpel, pruning shears, forceps, scissors, sharpener, hacksaw, etc.
Define the terms "rigor mortis", "algor mortis" and "livor mortis"?
Rigor mortis - contraction of the muscles
Algor mortis - body equilibrates with ambient temperature
Livor mortis - red discoloration of the skin due to settling of blood by gravity
Name the 4 different methods to obtain biopsies and briefly describe how you would obtain the sample?
Excisional - removal of the whole lesion
Incisional - portion of lesion is removed
Punch - collecting a representative sample of lesions
Needle core - used to collect deeper samples (liver via ultrasound)
Name the 7 different categories/types of lesions?
Degenerative
Anomalous
Metabolic
Neoplastic
Inflammatory
Traumatic
Vascular
Briefly describe the difference between a "morphologic diagnosis" and "etiologic diagnosis"?
Morphological diagnosis - concise summary of the important aspects of a lesion (pathological process and location, distribution, time frame, severity, key features)
Etiological diagnosis - concise summary of the cause and main lesion
What are the 5 main problems that pathologists encounter when receiving samples to examine?
Too few tissues
Missing vital organs
Lesions not sampled
Samples are too thick
Too little formalin for tissues