Lab 8

Question 1

What is the function of granulation tissue?

Answer 1

granulation tissue is repair tissue. It serves to fill in defects left by wounds and can also initiate a wall around an irritant that cannot otherwise be eliminated

Question 2

What does granulation tissue eventually turn into to produce scarring?

Answer 2

fibrous connective tissue

Question 3

This tissue is composed of well vascularized fibrous connected tissue infiltrated with large numbers of nuetrophils and granulation tissue. Provide a histopathologic diagnosis.

Answer 3

granulation tissue with acute inflammation at the surface

Question 4

What type of tissue is located here?

Answer 4

proliferating granulation tissue

Question 5

What type of tissue is located here?

Answer 5

more mature granulation tissue

Question 6

Identify this structure:

Answer 6

capillary buds located within granulation tissue

Question 7

Identify this structure:

Answer 7

loosely arranged fibroblasts

Question 8

Identify this structure:

Answer 8

polymorpho nuclear neutrophils (pmns)

Question 9

What is a mast cell?

Answer 9

a connective tissue cell of bone marrow origin that is typically found adjacent to blood vessels

Question 10

What is a mast cell important in?

Answer 10

mediating in inflammation because they contain vasoactive amines such as histamine and heparin

Question 11

What does metachromasia mean?

Answer 11

that a substance stains a different color than the color of the stan

Question 12

Describe this lesion.

Answer 12

There is a focal, exophytic and friable black mass cranial to the tip of the tail. On cut surface, the mass extends into the underlying musculature. There are multiple smaller, variably- sized and variably shaped masses with similar features located throughout the body (e.g. within liver, kidney, serosa of intestine and mesentery).

Question 13

There are secondary sites for this lesion throughout the body, provide a morphological diagnosis for this lesion.

Answer 13

Skin: malignant melanoma with distant metastasis

Question 14

What is the most likely cell type involved with this neoplasm?

Answer 14

melanocyte

Question 15

What is the name of the benign version of a neoplasm involving melanocytes?

Answer 15

benign melanoma or melanocytoma

Question 16

What is the name of the malignant version of a neoplasm involving a melanocyte?

Answer 16

malignant melanoma

Question 17

Describe this lesion.

Answer 17

There is locally extensive, poorly demarcated, firm, mass effacing the proximal tibia and expanding surrounding tissues of the stifle joint. The tibial epiphysis and proximal physis are hemorrhagic, with medullary trabecular lysis and cortical thinning. Thin spicules of bone radiate perpendicularly from the proximal tibial cortex, blending into the firm, fibrous proliferation of tissue around the stifle joint.

Question 18

What is happening to the medulla here?

Answer 18

it is lytic and hemorrhagic

Question 19

What is occuring here?

Answer 19

speculated boney proliferation extending from the periosteum into the surrounding soft tissue

Question 20

What is occuring here?

Answer 20

thinning and lysis of the cortical bone

Question 21

What is the morphological diagnosis of this neoplasm?

Answer 21

proximal tibia: neoplastic mass, focal, infiltrative

Question 22

Histologic examination of the lesion shows that the mass is composed of spindles cells (mesenchymal cells) resembling osteoblasts that surround osteoid matrix. The spindle cells have a high mitotic rate are seen invading and replacing normal medulla and cortical bone. Provide a morphologic diagnosis based on this information.

Answer 22

proximal tibia: osteosarcoma, primary site

Question 23

Is this lesion normal wound healing (i.e. a fracture callus) or is it a neoplastic process?

Answer 23

it is a neoplasm that suggests malignancy due to the infiltrative nature, advanced destruction of normal tissues, and high mitotic rate

Question 24

Describe this lesion.

Answer 24

Ribs: There are irregular bony proliferations protruding internally and externally on the following ribs: The majority of the bony protrusions are ventral and near the costochondral junction.

Question 25

What is occuring here?

Answer 25

a cartilaginous cap from the rib mass that is continuous with the cortical bone

Question 26

What is occuring here?

Answer 26

an irregular, smooth boney proliferation located at the costochonral junction

Question 27

Provide a gross morphological diagnosis for this lesion.

Answer 27

Ribs: multifocal, chronic, and boney proliferations

Question 28

Histologic examination showed that the masses are continuous with the cortical bone. They consist of well- organized caps of hyaline cartilage that is undergoing endochondral ossification at the base of the mass. No mitoses or destruction of the cortex/medulla are seen. Provide a histological morphologic diagnosis for this lesion.

Answer 28

multifocal, chronic, osteochondromas

Question 29

Is this lesion benign or a malignant lesion and why?

Answer 29

it is benign known as osteochondromatosis, it is not considered a true neoplasm but is most likely the result of dysplasia

Question 30

Describe this lesion.

Answer 30

Ribs: Focally and midway between the costocondral junction and head of the 9th rib, there is a smooth, firm mass that is attached to the rib. On cut surface, there is a small, thin fracture line transversing the cortex and medulla of the rib. The fracture is bridged on each side by white, firm tissue that is slightly less rigid than the surround normal bone (fracture callus).

Question 31

What is the morphological diagnosis of this neoplasm?

Answer 31

focal, transverse, chronic rib fracture with callus formation

Question 32

What are the possible differentials for this lesion?

Answer 32

fracture callus, osteosarcoma, and chondrosarcoma

Question 33

Describe this lesion.

Answer 33

At the distal end of the left medial lobe there is a firm, round, multi-lobulated mass. On cut surface the mass extends into the parenchyma and is mottled red and tan is slightly friable and contains multiple cysts that vary in size.

Question 34

What are the differentials for a nodular lesion in the liver?

Answer 34

hyperplasia, abcess, neoplasm, and granuloma

Question 35

Describe this lesion.

Answer 35

A firm multi-lobulated light tan to pink mass was present on mid-line, just cranial to and surrounding the pericardial sac and heart. The mass displaces the lung lobes caudodorsally and the trachea dorsally. On cut surface the mass was also light tan to pink.

Question 36

What is this?

Answer 36

a large, pale, multilobulated cranial mediastinal mass that surrounds the pericardium/heart and displaces the trachea and lungs dorsally

Question 37

Provide a gross morphological diagnosis for this lesion.

Answer 37

cranial mediastinal neoplasm

Question 38

Histologic examination revealed sheets of small to intermediate sized round cells that have replaced the normal thymic architecture. The round cells have a high mitotic index and there are multiple areas of necrosis. Provide a morphologic diagnosis.

Answer 38

Thorax: cranial mediastinal lymphocytic neoplasm (likely malignant lymphoma)

Question 39

At the time of necropsy, there was over 150 mL of serosanguinous fluid in the thorax cavity (hydrothorax). Describe how the respiratory distress and hydrothorax developed in this cat?

Answer 39

The lymphoma most likely grew large enough to obstruct lymphatic flow, compressed the trachea, and compressed the heart and lungs. The obstruction of the lymphatic vessels most likely resulted in the hydrothorax

Question 40

Describe this lesion.

Answer 40

Right forelimb, coronary band: On the lateral aspect of the right front coronary band, there was a large, firm, lobulated, raised, mottled dark red to tan, soft tissue mass (consistent with exuberant granulation tissue). On cut surface the mass was solid, mottled dark red to tan, contained areas of mineralization and extended to the dorsal aspect of P3.

Question 41

The histoologic appearance of this mass shows well vascularized fibrous connected tissue infiltrated with large numbers of nuetrophils and granulation tissue. Provide a histopathologic diagnosis.

Answer 41

Right forelimb, coronary band: chronic, focal, severe exuberant granulation tissue (proud flesh)