Test 2: lab 4 Flashcards
Give the morphologic diagnosis of the black mass on the first specimen:
What is the typical behavior of this pigmented lesion?
Malignant oral melanoma.
They are highly aggressive with both local invasion and widespread metastasis. They are the most frequently occurring malignant tumor in the oral cavity of dogs and have a poor prognosis. Amelanotic (non-pigmented) melanomas also occur and require histology for diagnosis, but, even then, the diagnosis can sometimes be challenging.
Describe
Morphologic diagnosis of this lesion:
There is marked proliferation of the gingiva surrounding the lower incisors and canine teeth. The proliferating tissue is pale tan and is nearly obscuring the incisors.
Severe locally extensive chronic fibrogingival hyperplasia
Name two other proliferative lesions of the canine mouth that occur along the gingival margin in dogs:
Peripheral odontogenic fibroma (POF) or acanthomatous ameloblastoma.
fibrogingival hyperplasia
Describe the behavioral differences between POF and AA and FGH
Fibrogingival hyperplasia is a reactive lesion, POF is a benign neoplasm, and acanthomatous ameloblastoma is a locally aggressive neoplasm that does not metastasize but can still lead to euthanasia due to extensive damage to the jaw and a tendency to recur even after surgery.
DOG STOMACH History: Older dog with inappetence, hematemesis (vomiting blood), melena (dark, tarry feces due to partially digested blood).
Description:
Morphologic diagnosis:
The stomach has a large, deep, focal ulcer approximately 4 cm X 3 cm X 0.5 cm extending to the serosal surface. There is an approximately 2 mm full-thickness perforation at the base of the ulcer. Surrounding the ulcer is an approximately 1.5 cm rim of very firm white tissue expanding the wall of the stomach (noticeable on palpation of the specimen in lab).
Gastric adenocarcinoma with ulcer and focal acute perforation
Other tissues that may be involved with Gastric adenocarcinoma ?
Gastric adenocarcinoma can metastasize to the local lymph nodes, lungs, and liver.
Other common causes of gastric ulcers include NSAIDS via inhibition of prostaglandin synthesis leading to reduced secretion of mucus and HCO3-, reduced blood flow, and decreased cell turnover. Stress associated with concurrent disease, transport, or irregular feeding intervals (performance horses!) causes release of endogenous corticosteroids that can also inhibit prostaglandin with similar effects. Mast cell tumors have also been associated with gastric ulcers, especially in dogs, since the neoplastic mast cells can produce excess circulating histamine, which increases gastric acid production. The ulcers often arise within the pyloric antrum and proximal duodenum.
What are the translucent foci in image (iii
Necrotic (“Punched-Out”) Peyer’s Patches
Given the history and these lesions, propose a likely morphologic diagnosis and etiology for the cat intestines:
This cat (photos I, ii, iii) had vomiting and severe diarrhea with severe depletion of all WBC lineages on CBC (complete blood count).
what is the pathogensis
necrotizing enteritis with GALT depletion; Feline Panleukopenia virus.
Crypt cell necrosis→ loss/reduced replacement of villus epithelium→ villus blunting and fusion→ crypt regeneration→ epithelial attenuation (immature enterocytes populating villus tips) → malabsorption/maldigestion→ osmotic draw → diarrhea
Propose a common bacterial pathogen that could cause these changes in both of these species:
Salmonella sp.
Given the histologic features showing capillary fibrin thrombi and necrosis involving mucosal epithelium and lamina propria, what do you propose is the primary mechanism of diarrhea in these specimens?
Exudation/Effusion (note the exudation/effusion will cause a secondary osmotic draw of fluid into the lumen with secondary malabsorption/maldigestion
Small intestine from an emaciated adult dairy cow experiencing a recent drop in milk production with the development
of watery diarrhea. The cow maintains an excellent appetite.
Description:
Morphologic diagnosis:
Description: The mucosa is diffusely thickened with a corrugated texture.
Morphologic diagnosis: Severe diffuse chronic granulomatous enteritis
Name the causative agent of Johne’s
Johne’s Disease; Mycobacterium avium, subsp. paratuberculosis
What is the primary mechanism of diarrhea in Johne’s
Effusion/exudation. Malabsorption/maldigestion and dysmotility are also a contributing factors.
This cat had intermittent diarrhea, vomiting, loss of appetite and weight loss.
Description:
Likely diagnosis:
Both the mucosa/submucosa and muscular wall of the small intestine are markedly thickened with a narrowed lumen.
The changes are characteristic of eosinophilic enteritis with muscular hypertrophy, a specific form of inflammatory bowel disease (IBD). A good morphologic diagnosis would be “severe diffuse chronic eosinophilic enteritis with smooth muscle hypertrophy.”
Histologically, there is diffuse mucosal and submucosal infiltration by eosinophils (can also have lymphocytes and plasma cells) with mural smooth muscle hypertrophy. The markedly thickened wall is associated with dysmotility which contributes to the diarrhea. Although this is a primary inflammatory lesion, it can produce secondary segmental obstruction.
This dog presented for vomiting and inappetence.
Description:
Diagnosis:
A red-purple segment of small intestine is expanded by invagination and telescoping of the proximal segment of intestine into the distal segment.
Intussusception.
Without surgical intervention, the passive congestion within the intussusceptum (the invaginated proximal segment of small intestine) will lead to ischemic necrosis and infarct. Translocation of bacteria through the compromised intestinal barrier will lead to septic peritonitis.
string in intestine will cause
If an ingested string or other linear foreign object becomes immobilized, (e.g., caught at the base of the tongue or pylorus), the intestine will “gather up” or “plicate” along its length. Peristalsis results in progressive mucosal erosion to ulceration as the string (arrow) acts as Gigli wire, leading to perforation and peritonitis.
Small intestine from a 11-year-old dog with a history of progressive weight loss, lethargy, diarrhea, and blood in the stool.
Description:
The wall of a 7 cm segment of small intestine is markedly expanded by pale tan to white tissue that forms a discrete nodular mass that expands and effaces the wall. The mesenteric lymph node is also enlarged and bulges on cut surfac
Prior to fixation, the tissue within this mass was soft and bulged on cut section. Cytologic impression smears showed atypical round cells with large round nuclei and scant basophilic cytoplasm. Based on these findings and the gross appearance, what is your morphologic diagnosis?
Small intestinal lymphoma with lymph node involvement. Intestinal lymphomas are seen in cats, dogs, and horses. Alimentary lymphomas are less than 10% of all canine lymphomas.
FERRET LIVER
This liver is from an overweight ferret with a week-long history of anorexia.
Description:
Diagnosis:
The liver is severely diffused enlarged with rounded lobar margins. The tissue is diffusely yellow and friable. Sections of the tissue float in water.
Hepatic lipidosis
This liver is from an overweight ferret with a week-long history of anorexia.
Likely pathogenesis in this case:
Anorexia → negative energy balance → increased mobilization of peripheral fat stores → rate of entry of fatty acids (FAs) into hepatocytes exceeds export from hepatocytes → accumulation of lipid vacuoles in cytoplasm of hepatocytes (hepatic lipidosis).
This liver is from a 10-year-old German shepherd dog.
Description (hint: consider the size of an adult German shepherd dog):
Name the condition:
The liver is severely diffusely small with irregular loss of tissue. All lobes consist of multiple round, brown nodules varying in size from 0.3 cm to 1.5 cm in diameter. These round nodules are separated by firm bands of tan fibrosis.
Cirrhosis
Given only the gross appearance of this liver, can you accurately predict the initial cause of liver injury
No, this is a non-specific chronic change to the liver. Cirrhosis is the final and irreversible result of many types of liver disease, including chronic inflammation or chronic exposure to hepatotoxins or hepatotoxic medications.
This liver is from a dog.
Description:
Morphologic diagnoses:
The liver is mottled tan to brown with many small depressed foci up to 0.3 cm in diameter of tissue loss and hemorrhage.
Severe multifocal acute hepatitis with hepatocellular necrosis and hemorrhage
DOG GALLBLADDER Gallbladder from a Shetland sheepdog. This dog presented for anorexia, vomiting, and diarrhea. The eyes and mucous membranes were discolored yellow. Bloodwork showed a bilirubin of 4.0 mg/dl (normal is less than 1.0
mg/dl).
Description:
Morphologic diagnosis
The gallbladder is distended and filled by shiny dark green-black gelatinous material containing lamellar striations.
Severe mucocele with distention of the gallbladder.
Gallbladder mucoceles may lead to obstruction of bile outflow and rupture of the gallbladder. Severe prolonged distention can progress to infarction of the gall bladder wall. Histologically, there is typically hyperplasia of the mucus-secreting glands of the mucosa. Impaired gallbladder motility and changes in cholesterol and lipid metabolism appear to play a role in pathogenesis. Dogs with hyperadrenocorticism have a greatly increased risk of gallbladder mucocele formation.
CAT LIVER
Description:
What is your main differential for a mass with this appearance in a cat?
Approximately 80% of the right lateral liver lobe is replaced by a tan, soft to firm, multilobulated, cystic mass.
Biliary cystadenoma
What are some other nodular masses that may be found in the liver?
DOG LIVER
Description:
Diagnosis
The liver parenchyma is effaced by numerous coalescing, firm, pale tan nodules ranging in diameter from 0.5 – 3.0 cm. Several of the nodules have depressed centers (umbilicated). The intervening liver tissue is compressed and discolored yellow to brown. In fresh specimens some nodules may appear green (like bile).
Cholangiocellular carcinoma
Cholangiocellular carcinoma
What makes the tissue firm?
Cholangiocellular carcinomas are associated with an abundant amount of dense fibrous connective tissue (desmoplasia). Robust desmoplasia, large numbers of pale tan nodules involving multiple lobes, and central necrosis with collapse (umbilication) of nodules are all common findings of cholangiocellular carcinomas that are not seen as often with hepatocellular neoplasms. Cholangiocellular carcinomas are highly infiltrative with metastatic spread throughout the liver, to regional lymph nodes, and within the peritoneal cavity (carcinomatosis). They may spread to other organs as well
DOG PANCREAS Tissue from a mixed-breed dog that got into the owners’ fast-food takeout dinner when they weren’t looking. A normal
tissue specimen has been included for reference.
Description of the affected pancreas (hint: the darker areas would be red in a fresh specimen):
Diagnosis
A portion of the pancreas is severely swollen, firm, and reddened, with hemorrhage and edema extending into the surrounding tissue.
Moderate acute regional pancreatic necrosis (necrotizing pancreatitis).
