Neoplastic and aging diseases of mice

Question 1

thymic LSA has a _____ incidence in ____ and ____ mice strains by 1 year and a high incidence in SCID mice

Answer 1

• near 100%
• AKR
• C58

Question 2

Which mouse strain has a high incidence of multicentric lymphoma

Answer 2

BALB/c mice

Question 3

Histiocytic sarcoma
- Predisposed strains

• Cell type of origin

Answer 3

• Aged B6 and SJL mice
• Kupffer cells and tissue macrophages

Question 4

Gross findings of histiocytic sarcoma in mice

Answer 4

• enlargement and nodularity to spleen, liver, uterus, vagina, kidney, lung, and/or ovaries

Question 5

Associated findings of histiocytic sarcoma

Answer 5

• erythrophagocytosis in HS arising from the liver
• Eosinophilic inclusions in renal tubular epithelium

Question 6

Rat mammary tumors are often ___-containing, while mouse mammary tumors are made up of

Answer 6

• collagen
• epithelial cells

Question 7

Gross findings of mammary neoplasia in mice

Answer 7

• often multicentric and multinodular, well-circumscribed (even if malignant)
• pale tan, firm, and may have areas of hemorrhage
• overlying skin may be ulcerated
• pulmonary metastasis possible

Question 8

Histopath findings of mammary neoplasia in mice

Answer 8

• variably sized cystic structures lined by neoplastic glandular epithelium
• cells are pleomorphic

Question 9

Strain susceptibility to Mammary neoplasia

Answer 9

• susceptible: C3H
• Resistant: BALB/c

Question 10

predisposing factors to Mammary neoplasia

Answer 10

• MMTV, chemical carcinogens, and hormones influence incidence
• Prolactin, progesterone, and estrogens influence development
• Multiparous FVB mice are prone to mammary tumors
• Stress induces mammary neoplasia in C3H/He mice

Question 11

Pulmonary neoplasia
- cell type of origin

• How do you classify adenoma vs. carcinoma
• clinical signs

Answer 11

• Arise from type II pneumocytes or Clara (club) cells
• classification based on tumor size
• usually no clinical signs

Question 12

Strain susceptibility

Answer 12

• near 100% incidence in A strain mice by 18-24 mos.

Question 13

Predisposing factors to pulmonary neoplasia

Answer 13

• enhanced incidence via Sendai virus or chemical carcinogens

Question 14

Hepatocellular neoplasias are usually _________ or _____

What types are noted on histopath

Answer 14

hepatocellular adenomas or carcinomas

Note that there are trabecular or solid types on histopath

Question 15

Strains predisposed to hepatocellular neoplasia

Answer 15

• A and DBA strains

Question 16

Predisposing factors to Hepatocellular neoplasia

Answer 16

Helicobacter associated with earlier onset and higher prevalence in A strain mice

Question 17

Harderian gland tumor
- Gross findings

• histopath findings
• behavior of neoplasm

Answer 17

gross:
- protrusion of the eye, porphyrin staining of periocular fur

Histopath
- lobulated, usually of papillary cystadenoma or solid adenoma morphology
- relatively well-differentiated epithelial cells with vacuolated cytoplams

behavior:
- adenocarcinomas are invasive but rare to metastasize

Question 18

• Strains predisposed to osteomas and osteosarcomas
• most common site for vertebral tumors
• what virus can also lead to bone tumors in mice

Answer 18

strains
- NOD mice
- Outbred OF-1 and CF-1 mice develop benign bone tumors

Region:
- lumbosacral region is most common site for vertebral tumors

virus causing bone tumors
- PyV of nude mice

Question 19

Pituitary gland adenomas
- Predisposed strains

• predisposed sex
• hormone produced by tumor

Answer 19

strains:
- common in B6 and Swiss mice
- FVB/N mice are very prone

Predisposed sex: females

• Hormone produce: prolactin

Question 20

Gross findings of pituitary gland adenomas

Histopath findings

Answer 20

• large, pale tan to red, soft, well-demarcated mass, often very hemorrhagic

solid, sinusoidal, or cystic patterns on histopath

behavior: grow expansively with compression of the brain

Question 21

Stain of choice for amyloidosis

Answer 21

Congo red

Question 22

Amyloidosis:
- strains with high prevalence and early onset

• Strains with high prevalence but late onset
• strains that are rarely affected

Answer 22

• A, SJL, and outbred Swiss mice
• B6 and B10 mice
• BALB/C3H, and DBA mice

Question 23

Strains predisposed to Soft tissue calcification

Answer 23

• BALB/c (right ventricular epicardial mineralization)
• C3H (Myocardium and ventricles and IVS, axial skeletal muscles)
• DBA (heart and many other organs)

Question 24

You find acidophilic crystals accumulated with macrophages MNGCs, alveolar spaces, and airways. What is your first thought?

What are these crystals comprised of?

Answer 24

Acidophilic macrophage pneumonia

• Ym1 and Ym2 chitinase, with iron, alpha-1 antitrypsin

Question 25

- Strains predisposed to acidophilic macrophage pneumonia - predisposing factors°°

Answer 25

- B6, 129, and Swiss mice - response to inflammation and/or diminished pulmonary clearance

Question 26

You find similar crystals in the cytoplasm of olfactory, nasal respiratory, middle ear, trachea, lung, stomach, gallbladder, bile duct, and pancreatic duct epithelium. Now what do you call it?

Answer 26

"Epithelial hyalinosis"

Question 27

What are some causes of hair loss in mice

Answer 27

- Barbering and trichotillomania (compulsive behavior/dominance issue) - mechanical muzzle alopecia (improper food/watering tool use) - Alopecia areata in C3H mice (autoimmune response) - Alopecia of B6 mice (multifactorial and behavioral disorder) - Clown syndrome (MHV infection on young mouse caused arrested hair follicle growth)

Question 28

Common cause of Auricular chondritis

Answer 28

- autoimmune disease response to metal ID tagging

Question 29

Causes of Gangrene of ears and limbs

Answer 29

- erosive inflammation and necrosis of pinnal margins (ears) - Sloughing of extremeties due to cotton nesting material (limbs) - frostbite (limbs, nude mice more at risk) Ringtail (caused by low humidity and high temperature)

Question 30

Hydrocephalus is relatively common in _____strains

Answer 30

C57BL strains

Question 31

Acallosity and hypocallosity are common in which strains

Answer 31

- BALB/c and 129 mice

Question 32

Microphthalmia/anophthalmia is common and unique to ____ mice strains _____ are predisposed and it is usually _____, affecting the ______

Answer 32

- C57BL - females - asymmetric - affecting the right eye

Question 33

Which auricle is usually affected by atrial thrombosis what are some predisposing factors which strain is predisposed

Answer 33

the left auricle predisposing factors: - usually 2° to amyloidosis or renal disease predisposed strain - BALB/c

Question 34

Murine Urologic Syndrome affects which strains predominantly

Answer 34

B6C3F1 and ICR strains

Question 35

Pathogenesis of MUS gross findings

Answer 35

proteinaceous plugs of ejaculate lodged in neck of urinary bladder or proximal urethra -> obstructive uropathy urinary bladder distention, possible hydronephrosis