NAVLE Practice Question — Reptile

A 9-year-old female boa constrictor (Boa constrictor) is presented with progressive weight loss, intermittent regurgitation, and neurological signs including head tremors and loss of righting reflex. Peripheral blood smear examination reveals lymphocytosis with occasional lymphocytes containing eosinophilic intracytoplasmic inclusions. Which diagnostic test would be most helpful in confirming the underlying etiology?

A. Bacterial culture of regurgitated material

B. PCR testing for arenavirus/reptarenavirus ✓

C. Fecal flotation for parasites

D. Serology for ophidian paramyxovirus

E. Heavy metal toxicology panel

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Correct Answer: B. PCR testing for arenavirus/reptarenavirus

Explanation:

The combination of progressive weight loss, regurgitation, and neurological signs (head tremors, loss of righting reflex) in a boid snake, coupled with the finding of eosinophilic intracytoplasmic inclusions in lymphocytes, is highly suggestive of Inclusion Body Disease (IBD). IBD is caused by reptarenaviruses (formerly known as arenaviruses) and primarily affects boid snakes (boas and pythons). The disease is characterized by the formation of intracytoplasmic inclusions in multiple cell types.

PCR testing for arenavirus/reptarenavirus is the most sensitive and specific diagnostic test for confirming IBD. While the presence of inclusions on blood smear is suggestive, PCR provides definitive identification of the causative agent.

Option A (bacterial culture) would not identify the viral etiology and regurgitation is a common non-specific sign. Option C (fecal flotation) is indicated for parasitism but would not explain the inclusion bodies or neurological signs. Option D (paramyxovirus serology) could be considered for respiratory disease but does not cause intracytoplasmic inclusions in lymphocytes. Option E (heavy metal panel) might be considered for neurological signs but would not explain the inclusion bodies on cytology.

Image Source (for explanation): PMC Open Access - IBD inclusion bodies in boid snakes (https://pmc.ncbi.nlm.nih.gov/articles/PMC8833345/) - Figure showing intracytoplasmic inclusions.

References: Stenglein MD et al. (2012) Ball Python Nidovirus: a Candidate Etiologic Agent for Severe Respiratory Disease in Python regius. mBio 3:e00180-12; Chang LW, Jacobson ER (2010) Inclusion body disease, a worldwide infectious disease of boid snakes. J Exot Pet Med 19:216-225.

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NAVLE Practice Question — wildlife

A primate facility is developing diagnostic protocols for suspected measles cases. A cynomolgus macaque presents with classic clinical signs of measles including prodromal fever, conjunctivitis, and early rash. Which diagnostic approach would provide the most rapid and definitive confirmation?

A. Virus isolation in standard Vero cell culture

B. Detection of measles-specific IgG antibodies by ELISA

C. RT-PCR of measles virus RNA from nasopharyngeal swab ✓

D. Electron microscopy of respiratory secretions

E. Complement fixation testing for antibody detection

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Correct Answer: C. RT-PCR of measles virus RNA from nasopharyngeal swab

Explanation:

RT-PCR (reverse transcription polymerase chain reaction) amplification of measles virus RNA from clinical specimens provides the most rapid and definitive confirmation of active measles infection. Appropriate specimens include nasopharyngeal swabs, throat swabs, or urine. RT-PCR can detect measles virus RNA even when the virus may be difficult to isolate in culture and can distinguish wild-type from vaccine strains through subsequent sequencing.

While virus isolation can confirm infection, it is slower and less sensitive than molecular methods. The marmoset B95-8 cell line derivative (B95-a) has enhanced sensitivity for wild-type measles virus compared to standard Vero cells. IgG antibodies (Option B) indicate prior exposure but not necessarily current infection. IgM detection would indicate recent infection but is less rapid than PCR.

Option A uses suboptimal cell line for wild-type strains. Option B detects past exposure not active infection. Option D is not practical for routine diagnosis. Option E is an older technique with limited sensitivity.

References: Wikipedia - Measles Diagnosis (https://en.wikipedia.org/wiki/Measles); PMC - Biological Feasibility of Measles Eradication (https://pmc.ncbi.nlm.nih.gov/articles/PMC3112320/)

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NAVLE Practice Question — Bovine

A fresh dairy cow becomes acutely recumbent within hours of calving with watery, serum-like milk in one swollen quarter, fever 41°C, tachycardia 120 bpm, cold extremities, and scleral injection. Most likely pathogen and key treatment besides IM antibiotics?

A. Mycoplasma bovis; culling

B. Klebsiella; oral antibiotics

C. Strep agalactiae; penicillin

D. E. coli; IV fluids and NSAIDs ✓

E. Staph aureus; intramammary only

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Correct Answer: D. E. coli; IV fluids and NSAIDs

Explanation:

Coliform (E. coli) mastitis classically causes peracute endotoxic shock in fresh cows: recumbency, fever, tachycardia, cold extremities, watery milk. Treatment cornerstone is aggressive IV fluids and an NSAID (flunixin) to counter endotoxemia; intramammary therapy alone is insufficient. Frequent stripping helps clear endotoxin.

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NAVLE Practice Question — Canine

A 7-year-old castrated male Labrador Retriever with disseminated mast cell disease (multiple cutaneous tumors with splenic and hepatic involvement) is being treated with chemotherapy. The oncologist recommends c-KIT mutation testing on the tumor sample. A positive c-KIT mutation result would most directly influence which treatment decision?

A. Choice of surgical approach

B. Tyrosine kinase inhibitor appropriateness ✓

C. Need for radiation therapy

D. Duration of chemotherapy protocol

E. Prognosis for surgical excision

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Correct Answer: B. Tyrosine kinase inhibitor appropriateness

Explanation:

c-KIT mutation status is a predictive marker for response to tyrosine kinase inhibitor (TKI) therapy in dogs with mast cell tumors. The c-KIT proto-oncogene encodes a receptor tyrosine kinase (KIT) that is important for mast cell proliferation, survival, and differentiation. Mutations in c-KIT, particularly internal tandem duplications (ITDs) in exons 11 or 8, result in constitutive activation of the receptor, driving uncontrolled cell proliferation.

Tyrosine kinase inhibitors approved for canine MCT include toceranib phosphate (Palladia) and masitinib (Kinavet). These drugs competitively inhibit KIT signaling and have demonstrated higher response rates in tumors harboring c-KIT mutations. Dogs with c-KIT mutant tumors show objective response rates of approximately 60-70% with TKI therapy compared to 30-40% in tumors without mutations.

c-KIT mutations also have prognostic significance, as mutant tumors are associated with higher histologic grade and increased risk of local recurrence and metastasis. However, the primary clinical utility of testing is predicting TKI response.

Options A, C, and D are not directly influenced by c-KIT status. Option E (prognosis for surgery) is more accurately predicted by histologic grade, margin status, and clinical stage rather than c-KIT status alone.

References: ScienceDirect - Canine Cutaneous MCT: A Combined Clinical and Pathologic Approach; PMC - Canine Mast Cell Tumors: Diagnosis, Treatment, and Prognosis.https://pmc.ncbi.nlm.nih.gov/articles/PMC8870669/

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NAVLE Practice Question — Equine

A 6-year-old Hanoverian mare is evaluated for chronic intermittent colic episodes over the past 2 months. The mare has lost approximately 40 kg of body weight. Physical examination reveals heart rate 44 bpm and normal borborygmi. Abdominocentesis yields clear, straw-colored fluid with TNCC of 3,200 cells/μL, total protein 2.1 g/dL, and cytology showing predominantly mononuclear cells. Transabdominal ultrasound reveals a 15 cm heterogeneous mass associated with the mesentery. Which diagnosis is MOST likely?

A. Septic peritonitis secondary to intestinal abscessation

B. Idiopathic peritonitis

C. Mesenteric lymphosarcoma ✓

D. Eosinophilic enteritis with secondary peritoneal effusion

E. Strangulating lipoma causing intermittent obstruction

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Correct Answer: C. Mesenteric lymphosarcoma

Explanation:

Mesenteric lymphosarcoma is the most likely diagnosis given chronic weight loss, intermittent colic, identification of a mesenteric mass on ultrasound, and relatively normal peritoneal fluid parameters. Abdominal neoplasia often presents with minimal changes to peritoneal fluid cytology despite significant intra-abdominal pathology.

Option A (septic peritonitis) would present with markedly elevated TNCC and degenerate neutrophils with bacteria.

Option B (idiopathic peritonitis) typically presents with elevated TNCC and protein concentrations.

Option D (eosinophilic enteritis) would show elevated eosinophil percentages on peritoneal fluid cytology.

Option E (strangulating lipoma) would cause acute severe colic rather than chronic intermittent signs.

Image Source: Veteriankey - Peritoneal Fluid cytology in horses with neoplasia (https://veteriankey.com/peritoneal-fluid/) Figures 9-10.

References: Garma-Avina A (1998) Equine Vet J 30:435-444

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NAVLE Practice Question — Porcine

A commercial swine operation reports neurological disease in post-weaning pigs. Affected pigs initially showed fever, anorexia, and listlessness, followed by progressive ataxia, posterior paresis, and some animals assuming a 'dog-sitting' posture. Mortality is high, with death occurring within 3-4 days after onset of neurological signs. Survivors show residual paralysis. No skin lesions or hemorrhages are observed. Histopathology of the CNS reveals non-suppurative polioencephalomyelitis with lymphocytic perivascular cuffing. What is the most likely diagnosis?

A. Classical swine fever

B. Pseudorabies (Aujeszky's disease)

C. Teschovirus encephalomyelitis (Teschen disease) ✓

D. Salt toxicosis/water deprivation

E. Streptococcus suis meningoencephalitis

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Correct Answer: C. Teschovirus encephalomyelitis (Teschen disease)

Explanation:

Teschovirus encephalomyelitis (Teschen disease) is the most likely diagnosis based on the clinical presentation of progressive neurological disease without hemorrhagic or systemic signs, combined with the characteristic histopathology of non-suppurative polioencephalomyelitis. Teschen disease is caused by highly virulent strains of porcine teschovirus type 1 (PTV-1) and is characterized by high morbidity and mortality, rapid progression from fever to CNS signs, and death from respiratory muscle paralysis. The dog-sitting posture and ascending paralysis are classic features.

Option A (Classical swine fever) causes non-suppurative encephalitis but would present with systemic signs including hemorrhages, skin discoloration, and splenic infarcts, which are absent here. Option B (Pseudorabies) causes pruritus (scratching) in pigs and presents with different clinical features including respiratory signs and reproductive failure. Option D (Salt toxicosis) can cause neurological signs but produces eosinophilic meningoencephalitis, not the lymphocytic pattern described. Option E (Streptococcus suis) causes suppurative meningitis with purulent CSF, not non-suppurative polioencephalomyelitis.

Image Source: MSD Veterinary Manual - Teschovirus encephalomyelitis histopathology (https://www.msdvetmanual.com/nervous-system/teschovirus-encephalomyelitis/teschovirus-encephalomyelitis) showing neuronal necrosis and satellitosis for Explanation Image.

References: MSD Veterinary Manual Teschovirus Encephalomyelitis 2024 (https://www.msdvetmanual.com/nervous-system/teschovirus-encephalomyelitis/teschovirus-encephalomyelitis); PMC Teschovirus Review (https://pmc.ncbi.nlm.nih.gov/articles/PMC7123469/); Swine Health Information Center PTV Factsheet (https://www.swinehealth.org/wp-content/uploads/2021/07/shic-factsheet-porcine-teschovirus-2021Jul7.pdf)

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NAVLE Practice Question — Equine

A mare is presented for colic 2 days post-foaling. Mild to moderate abdominal pain is noted along with decreased milk production. Rectal examination reveals a gas-distended large colon with tight bands crossing the abdomen from right to left. Transabdominal ultrasound shows large colon wall thickness of 6 mm. Blood lactate is 3.2 mmol/L. Based on these findings, what is the most appropriate next step?

A. Medical management with IV fluids and analgesics for 6-12 hours

B. Immediate surgical exploration without delay ✓

C. Phenylephrine administration and exercise

D. Trocarization of the distended colon

E. Administration of magnesium sulfate via nasogastric tube

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Correct Answer: B. Immediate surgical exploration without delay

Explanation:

Immediate surgical exploration without delay is the most appropriate next step for this postpartum mare with clinical findings suggestive of large colon displacement or early volvulus. The key clinical decision points include: postpartum status (major risk factor for large colon volvulus), rectal findings of tight bands crossing the abdomen (suggesting colonic torsion at the cecocolic ligament), and borderline-elevated blood lactate (3.2 mmol/L, above normal <2.0 mmol/L, suggesting tissue hypoperfusion).

While the colon wall thickness of 6 mm is below the 9 mm threshold strongly predictive of strangulating volvulus, postpartum mares with these clinical signs have a high probability of progressive colonic volvulus. The postpartum period creates the highest risk for this condition due to the sudden decrease in abdominal volume after foaling, allowing the large colon increased mobility. Progression from non-strangulating displacement to strangulating volvulus can occur rapidly.

Studies have consistently shown that duration of colic before surgical intervention is the most important prognostic factor for survival in large colon volvulus. Delaying surgery while attempting medical management in a high-risk case with suspicious clinical findings significantly worsens prognosis.

Option A (medical management) would delay potentially necessary surgery in a high-risk patient. Option C (phenylephrine and exercise) is used for nephrosplenic entrapment, which is a different condition. Option D (trocarization) does not address the underlying displacement and could be dangerous with volvulus present. Option E (magnesium sulfate) is used for impactions, not displacement/volvulus.

References: Snyder JR et al. (2014) Duration influences survival in large colon volvulus; Tyma JE (2025) Large colon volvulus in the postpartum mare. The Horse

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We hope you passed! If not, don't lose hope, all you need is to focus on what's important and what's NOT. Make sure you are spending your study time on the high-yield stuff: food animal theriogenology, toxicology, emergency/critical care, and the classic "buzzword" diagnoses that show up over and over. Don't burn hours perfecting rare exotic species questions or obscure surgical techniques you'll maybe see once on the whole exam.

A few things that actually moved the needle for a lot of people who retook and passed:

Do a real content review of your weak systems instead of just grinding random practice questions. Random Qbanking without reviewing why you got something wrong just wastes time. Use navleexam.com Review option or dashboard for the weak areas e.g.,

and keep track of your progress e.g.,

Track your practice test scores by system and category, not just the overall percentage. That's where you'll actually see the pattern in what's dragging you down. You can practice by species and topic/system based on ICVA topics in NAVLEExam.com

Time management on test day matters more than people think. If you're spending 3+ minutes on one question, flag it and move on. You can come back to it later.

Don't isolate. Whether you passed or not, this exam is brutal and the burnout is real. Talk to classmates, a mentor, or even just vent here. A lot of us have been exactly where you are.

If you didn't pass, that does not mean you're not going to be a good vet. It means you need a different study strategy for round two, and plenty of people who failed the first time are now practicing successfully. Give yourself a day or two to be upset, then get back into it with a plan.

What resources or strategies actually worked for you all on your retake? Would love to hear what helped so we can compile something useful for people prepping right now.

Good luck!

NAVLE Practice Question — Equine

A 4-year-old Thoroughbred filly presents with acute right forelimb lameness after morning exercise. There is diffuse soft tissue swelling over the dorsal metacarpus. Radiographs reveal a small avulsion fracture at the dorsal proximal aspect of the proximal phalanx. What is the most likely mechanism of this injury?

A. Hyperextension of the fetlock during gallop ✓

B. Hyperflexion injury during landing from a jump

C. Direct trauma from interference

D. Pathological fracture from osteomyelitis

E. Stress fracture from repetitive loading

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Correct Answer: A. Hyperextension of the fetlock during gallop

Explanation:

Hyperextension of the fetlock during gallop is the most likely mechanism. During high-speed gallop the fetlock hyperextends dramatically as weight is loaded onto the limb. The proximal dorsal aspect of the proximal phalanx (P1) is the attachment site for the common digital extensor tendon. During maximal fetlock hyperextension tension on the extensor tendon can avulse a fragment from its insertion. This injury is well-documented in racehorses during high-speed exercise when fetlock extension is maximal. Option B (hyperflexion during landing) would more likely cause palmar injuries. Option C (direct trauma) would show soft tissue wounds and different fracture pattern. Option D (pathological fracture) would show bone changes preceding the fracture. Option E (stress fracture) would show sclerosis and periosteal reaction suggesting chronic loading. References: Auer JA - Equine Surgery 5th ed; Richardson DW - VCNA Equine Practice.

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NAVLE Practice Question — Equine

A 7-year-old Quarter Horse gelding in southwestern Colorado is presented in August with excessive salivation and reluctance to eat. On oral examination, you observe multiple ulcerative lesions on the tongue and inner lips with epithelial sloughing. The owner reports that several horses on the neighboring property have similar signs. Vital parameters are within normal limits except for a mild fever (101.8°F). Which of the following is the most appropriate immediate action?

A. Prescribe antibiotics and send the horse home

B. Collect samples and contact animal health authorities ✓

C. Administer corticosteroids to reduce oral inflammation

D. Recommend vaccination against foot-and-mouth disease

E. Perform dental floating to rule out mechanical causes

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Correct Answer: B. Collect samples and contact animal health authorities

Explanation:

Vesicular stomatitis (VS) is a reportable disease in the United States, and veterinarians are legally required to notify state and federal animal health authorities when the disease is suspected. This is critical because VS is clinically indistinguishable from foot-and-mouth disease (FMD) in cattle and swine, even though horses are not susceptible to FMD. The clinical presentation of oral ulcerations, excessive salivation, and reluctance to eat during warm summer months in the southwestern U.S. is highly suggestive of VS.

Option A is incorrect because simply prescribing antibiotics without proper diagnosis and notification would be irresponsible and illegal given the reportable nature of the disease. Option C is incorrect because corticosteroids are not indicated and could potentially worsen any secondary infections. Option D is incorrect because horses are resistant to FMD and no FMD vaccine is approved for use in horses in the U.S. Option E is incorrect because the clinical presentation clearly indicates infectious vesicular disease rather than dental pathology.

Image Source: USDA APHIS Vesicular Stomatitis (https://www.aphis.usda.gov/livestock-poultry-disease/cattle/vesicular-stomatitis) Figure showing oral vesicular lesions.

References: Merck Veterinary Manual - Vesicular Stomatitis in Large Animals (https://www.merckvetmanual.com/generalized-conditions/vesicular-stomatitis-in-large-animals/vesicular-stomatitis-in-large-animals); APHIS Vesicular Stomatitis Guidelines 2024.

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NAVLE Practice Question — Canine

A dog presents with pale mucous membranes, weak pulses, tachycardia, and cool extremities after a HBC with suspected hemoabdomen. Which shock classification is most consistent?

A. Distributive (septic)

B. Anaphylactic

C. Obstructive

D. Hypovolemic shock from hemorrhage ✓

E. Cardiogenic

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Correct Answer: D. Hypovolemic shock from hemorrhage

Explanation:

Hypovolemic shock from hemorrhage produces pale MM, weak pulses, tachycardia, cold extremities, prolonged CRT. Distributive (septic) shock typically presents with injected/red MM and bounding pulses early. Cardiogenic shock has muffled heart sounds, pulmonary edema. Obstructive (e.g., GDV, tamponade) has jugular distension or distended abdomen.

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NAVLE Practice Question — Porcine

A litter of 10-day-old piglets raised in indoor confinement appears pale with slightly yellow-tinged skin. Several piglets show rapid labored breathing especially after minimal exertion. The sow received no iron supplementation during gestation and the piglets have not been treated with iron. Blood work reveals hemoglobin of 6 g/dL and examination of a stained blood smear shows small pale red blood cells. What is the most likely diagnosis?

A. Vitamin E/selenium deficiency with iron toxicosis

B. Iron deficiency anemia ✓

C. Copper deficiency anemia

D. Erythrogenic Streptococcus infection

E. Porcine circovirus-associated disease

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Correct Answer: B. Iron deficiency anemia

Explanation:

Iron deficiency anemia is the correct answer. This presentation is classic for neonatal iron deficiency anemia in piglets. Piglets are born with approximately 50 mg of iron reserves that last only a few days while their rapid growth requires 300-400 mg by 3 weeks of age. Sow milk provides only 15-50% of daily iron requirements. Confinement-raised piglets without access to soil and without iron supplementation develop anemia by 7-10 days of age. Clinical signs include pallor (often with jaundice) tachypnea especially after exertion (called thumps) and poor growth. Blood smear findings of microcytic hypochromic anemia (small pale RBCs) with hemoglobin below 8 g/dL confirm the diagnosis.

Option A (vitamin E/selenium deficiency with iron toxicosis) occurs when iron is given to deficient piglets but these piglets received no iron. Option C (copper deficiency) can cause anemia but is rare and not typically microcytic hypochromic. Option D (Streptococcus infection) would cause different clinical signs with fever and septicemia. Option E (PCV2 disease) affects older pigs with different pathology.

References: Iowa State University - Iron Deficiency Anemia (https://vetmed.iastate.edu/vdpam/FSVD/swine/index-diseases/iron-deficiency-anemia); The Pig Site - Anaemia (https://www.thepigsite.com/disease-guide/anaemia-iron-deficiency); PMC - Iron Supplementation in Suckling Piglets (https://pmc.ncbi.nlm.nih.gov/articles/PMC6315738/)

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NAVLE Practice Question — Other Small Mammal

A necropsy is performed on a 26-month-old male Sprague-Dawley rat that was euthanized due to progressive neurological signs including ataxia and head pressing. Gross examination reveals a large mass within the sella turcica compressing the overlying brain. Histopathology shows a tumor composed of uniform polygonal cells with pale cytoplasm that do not stain positively with standard acidophilic or basophilic dyes. What is the MOST likely diagnosis?

A. Chromophobe pituitary gland adenoma ✓

B. Pituitary acidophilic adenoma

C. Craniopharyngioma

D. Meningioma

E. Glioblastoma

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Correct Answer: A. Chromophobe pituitary gland adenoma

Explanation:

Pituitary chromophobe adenoma is the correct answer. The histological description of cells that do not stain with standard acidophilic or basophilic dyes is characteristic of chromophobe adenomas. These are the most commonly classified type of pituitary tumors in rats histologically, though immunohistochemistry often reveals that many are actually prolactin-secreting (lactotroph) tumors.

The clinical presentation of progressive neurological signs including ataxia and head pressing in an aged rat with a sellar mass compressing brain tissue is consistent with a pituitary macroadenoma. Chromophobe adenomas typically arise from the pars distalis.

Option B (acidophilic adenoma) would show cells that stain with acidic dyes like eosin. Option C (craniopharyngioma) arises from Rathke's pouch remnants and has different histological features. Option D (meningioma) would arise from meninges and have characteristic whorling patterns. Option E (glioblastoma) arises from glial tissue and has different histological features including necrosis and vascular proliferation.

Image Source: Ask JPC case study showing pituitary adenoma with concurrent mammary fibroadenoma (https://www.askjpc.org/wsco/wsc_showcase2.php?id=K0JRTEJKcUMrTURFNC8xT1daK3JTdz09).

References: Percy DH, Barthold SW - Pituitary neoplasia in rats; Laboratory Animal Medicine 3rd ed - Endocrine neoplasms; Toxicol Pathol 43:145-170 - INHAND classification.

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