Jan 012000

Case of the month is our diagnostic challenge. We present cases seen by Cornell University’s Clinical Pathology Laboratory. These cover the gamut of venous blood smears, cytologic specimens and result (CBC, chemistry) interpretation, including those pesky erroneous results (usually due to preanalytical errors). A new case will be presented every month. Test yourself with the questions and photomicrographs and make your own diagnosis! The answer along with explanations and discussion is provided on the following page to see how close you came to the diagnosis.

We also have an index of our previous cases (with answers) if you wish to see a list of all the cases. Please note, that the search tool does not search case of the month (yet!).

Jul 012017

Laboratory data from a jaundiced dog

Case presentation

A 9 year-old female spayed Pomeranian was presented to the Cornell University Hospital for Animals (CUHA) Emergency Service as a referral for markedly increased liver enzymes and cholesterol. The dog presented to the referring veterinarian with a two day history of vomiting, constipation, inappetence, and lethargy. After two days of medical therapy with no improvement, the dog was referred for further diagnostic testing and treatment.

Upon presentation to CUHA, the dog was bright, alert, responsive, and anxious.  Vital signs (temperature, pulse, and respiratory rate) were within normal limits. On physical examination, the dog was uncomfortable on abdominal palpation and the liver was palpably enlarged.  Jaundice of the skin and sclera OU were also observed.  The only other physical examination abnormality was a grade 1/4 luxating right patella.  Blood was collected for a complete blood count (CBC) and serum chemistry panel; relevant results of which are presented below. Evaluate the provided results and answer the questions posed below:

Table 1: Complete hemogram, EDTA
Test Result Reference interval Unit
WBC 15.7 5.7-14.2 thou/ul
Segmented neutrophils 13.0 2.7-9.4 thou/ul
Band neutrophils 0.0 0.0-0.1 thou/ul
Lymphocytes 0.5 0.9-4.7 thou/ul
Monocytes 2.0 0.1-1.3 thou/ul
TP-ref 9.0 5.9-7.8 g/dL
RBC morphology Moderate rouleaux formation
Plasma appearance Marked icterus


Table 2:  Chemistry, serum
Test Result Reference interval Unit
Total protein 5.2 5.3-7.0 g/dL
Albumin 2.8 3.1-4.2 g/dL
Globulin 2.4 1.9-3.6 g/dL
Glucose 142 63-118 mg/dL
ALT 2698 20-98 U/L
AST 564 14-51 U/L
Alkaline phosphatase 3590 17-111 U/L
GGT 309 0-6 U/L
Total bilirubin 16.3 0.0-0.2 mg/dL
Direct bilirubin 14.1 0.0-0.1 mg/dL
Indirect bilirubin 2.2 0.0-0.2 mg/dL
Cholesterol 782 138-332 mg/dL
Creatine kinase 1478 48-261 U/L
Iron 261 78-214 ug/dL
Transferrin saturation 77  23-61 %


  1. What does rouleaux formation of red blood cells (RBCs) indicate? 
  2. What are three explanations for the marked discrepancy between the total protein result on the CBC and chemistry panel in this case? Which result do you think is a better reflection of the patient’s total protein concentration?
  3. What pathologic processes can be identified based on the provided chemistry results? What are your differential diagnoses and what diagnostic test would you recommend?

Answers on next page

Jun 012017

Liver aspirate from a dog


Case information

A 9-year-old male castrated Labrador Retriever presented to the Cornell University Hospital for Animals for a 3-day history of vomiting and anorexia and a 1-day history of diarrhea. The dog had been administered carprofen 3 weeks earlier for progressive right forelimb lameness. The dog was up to date on core vaccinations and received a booster for leptospirosis 3 weeks prior. The patient was bright, alert, and responsive with normal vital parameters. No major abnormalities were noted on physical examination. Blood was taken for a hemogram and biochemistry profile and a voided urine was collected and submitted for urinalysis. The hemogram results were within reference intervals. Relevant results for the biochemistry profile and urinalysis are shown below.

Table 1: Pertinent biochemistry results
Test Results Units Reference interval
ALT 1,469 H U/L  20-98
AST 299 H U/L  14-51
ALP 198 H U/L 17-111
GGT 3 U/Ll 0-6
Total bilirubin* 1.4 H mg/dL 0-0.2
Urea nitrogen 32 mg/dL 10-32
Creatinine 2.1 H mg/dL 0.6-1.4
Glucose 91 mg/dL 63-118
* Mixture of indirect and direct bilirubin


Table 2: Pertinent urinalysis results
Test Results Units
Urine specific gravity 1.020 units
Protein 100 (moderate) mg/dL
Glucose 1000 (large) mg/dL
Bilirubin Small
Casts 1-2 granular /LPF


Abdominal ultrasonographic results did not reveal any abnormalities. Regardless, the liver was aspirated and smears were submitted for cytologic evaluation. Evaluate the representative photomicrographs of the direct smear of the liver aspirate and answer the questions posed below:

  1. How would you interpret the changes in the biochemical panel?
  2. Is a cause for these changes evident in the liver aspirate?
  3. What is going on in the kidney and how do you explain the renal-related results?


Figure 1: Liver aspirate (50x objective)


Figure 2: Liver aspirate (100x objective)


Figure 3: Liver aspirate (50x objective)

Answers on next page

May 012017

Kidney and third eyelid swelling in a dog


Case Information

A 12 year old male neutered mixed breed dog was brought to the Cornell University Veterinary Specialists (Cornell’s satellite clinic in Connecticut) for evaluation of 3 abdominal masses involving the spleen, kidney and mesentery. The dog also had a prominent swelling of the third eyelid that was reported to have a mass-like effect. All four of the lesions were aspirated and submitted for cytological evaluation.

The splenic aspirate contained components of red and white pulp, with no atypical cells or evidence of inflammation. The aspirate of the mesenteric mass contained free lipid admixed with blood. Photomicrographs of the kidney mass (Figure 1) and the swelling in the third eyelid (Figure 2) are shown below.


  1. Which lesion is likely the primary site?
  2. If the third eyelid mass was not present, how would this change the differential diagnosis list?


Figure 1A: Renal aspirate (20x objective)


Figure 1B: Renal aspirate (50x objective)


Figure 2A: Third eyelid (50x objective)


Figure 2B: Third eyelid (50x objective)


Answers on next page.

Apr 012017

Peripheral blood from a cat

Case information

Whole blood from a 3 year old male neutered Himalayan cat was collected into an EDTA tube and submitted to the Animal Health Diagnostic Center at Cornell University for a complete blood count. The submitting hospital provided no clinical history.

Review the pertinent data generated by the automated hematology analyzer (ADVIA 2120) and evaluate the photomicrographs below to answer the following questions:

Complete Blood Count (CBC) – Truncated; Data from analyzer

Analyzer data


  1. For which cell line is the analyzer clearly reporting spuriously decreased results?
  2. What is an artifact on a typical serum biochemistry panel that may be associated with this condition (in dogs), and what other type of specimen could you evaluate to confirm the artifact?
  3. How would you classify the large cells in Figures 2-3?

Figure 1. Peripheral blood smear. (Wright's stain, 20x objective)

Figure 1. Peripheral blood smear (Wright’s stain, 20x objective).

Figure 2. Large cell in the peripheral blood. (Wright's stain, 100x)

Figure 2. Peripheral blood smear (Wright’s stain, 100x objective).

Figure 3. Large cell on a peripheral blood smear. (Wright's stain, 100x)

Figure 3. Peripheral blood smear (Wright’s stain, 100x objective).

Answers on next page.

Mar 012017

Laboratory data from a vomiting painful cat

Case Information

A 3 year old male neutered domestic short haired cat, presented to Cornell University Hospital for Animals Emergency Service with a 24 hour history of inappetence and acting painful when picked up. The cat had also vomited several times but was drinking water.

On presentation, the cat was agitated, alert, responsive and vital parameters (temperature, pulse and respiration) were within normal limits. The cat was extremely painful on caudal abdominal palpation, but appeared to have a large bladder. A complete blood count (CBC) and serum chemistry was summited for analysis. A urinary catheter was passed with some difficulty but urine was obtained and submitted for urinalysis.

Review the laboratory data provided and answer the following questions (only abnormal and pertinent laboratory data has been included).

Complete Blood Count (CBC)Slide1
Serum Chemistry PanelSlide2


  1. How would you interpret the leukogram?
  2. What type of acid-base disturbance(s) can you identify from the serum chemistry panel?
  3. What other diagnostic tests should be performed in this case?

Answers on next page.

Feb 012017

Peritoneal fluid from an alpaca

Case information

A 6 year old female alpaca presented to the Cornell University Large Animal Hospital with a history of recumbency, anorexia, and dull mentation. Initial physical examination and diagnostic testing showed the animal was dehydrated and had clinical signs consistent with a proximal intestinal obstruction (decreased fecal output, significantly distended third gastric compartment, empty small intestine, and a shadowing object in the caudal aspect of the duodenal ampulla on abdominal ultrasonography). The hemogram showed a mild lymphopenia of 0.2 thousand/µL (reference interval, 1.1-5.5 thousand/µL), likely due to stress. Pertinent biochemical results are shown on the table below:

Analyte Result RI Units
Sodium 160 149-157 mEq/L
Chloride 106 106-116 mEq/L
Bicarbonate 41 22-34 mEq/L
AST 1062 119-286 U/L
SDH 117 0-7 U/L
GLDH 540 3-19 U/L
GGT 155 8-35 U/L
Bilirubin 0.1 0-0.1 mg/dL

The patient was taken to surgery for duodenal enterotomy and third gastric compartment gastrotomy. Surgery revealed two bezoars, one partially obstructing the distal third gastric compartment and another obstructing the duodenal ampulla. An increased amount of peritoneal fluid was found adjacent to the obstructed duodenum. The bezoars were surgically removed and a sample of peritoneal fluid was collected and submitted for cytologic evaluation.

The submitted peritoneal fluid was yellow to light-red in color and opaque, with total protein by refractometry of 2.7 g/dL. The total nucleated cell count was 6.5 thousand/µL and a red blood cell count was 65.1 thousand/µL. Direct and sediment smears from the submitted fluid were prepared.

Evaluate the representative photomicrographs of the peritoneal fluid shown below, consider the biochemistry results, and answer the following questions:

  1.  What type of metabolic derangement is present?
  2.  Identify and evaluate the cells labeled as “A” and “B” in Figure 2. 
  3. What additional diagnostic tests would you do in this case?

Fig1. Peritoneal fluid from an alpaca (Wright's stain, 20x objective)

Figure 1. Peritoneal fluid from an alpaca (Wright’s stain, 20x objective)

Fig2. Peritoneal fluid from an alpaca (Wright's stain, 50x objective)

Figure 2. Peritoneal fluid from an alpaca (Wright’s stain, 50x objective)

Figure3. Peritoneal fluid from an alpaca (Wright's stain, 100x objective)

Figure 3. Peritoneal fluid from an alpaca (Wright’s stain, 100x objective)

Figure4. Peritoneal fluid from an alpaca (Gram stain, 100x)

Figure 4. Peritoneal fluid from an alpaca (Gram stain, 100x objective)

 Answers on next page

Jan 012017

Tracheal wash from a horse

Case information

An 8 year old Morgan gelding presented to the Cornell University Hospital for Animals with a 3 week history of serohemorrhagic skin lesions and a 1 week history of a progressively worsening cough. The horse had also recently lost 100 lb. On physical examination, multifocal oozing lesions were present on the left hip, lower aspects of three limbs and neck. No abnormal lung sounds were detected on auscultation with or without a rebreathing bag. Thoracic ultrasonographic and radiographic examination revealed diffuse lung consolidation and pleuritis, with a mixed pulmonary pattern and coalescing nodules, respectively.  Blood samples were taken for a hemogram plus fibrinogen by heat precipitation and chemistry profile.

Hemogram abnormalities included a mild neutrophilia of 7.3 thou/uL (reference interval: 2.7–6.6 thou/uL) and a mild hyperfibrinogenemia of 400 mg/dL (reference interval, 0-200 mg/dL). There was a mild hypoalbuminemia (2.5 g/dL, reference interval: 3.0–3.7 g/dL) and hyperglycemia (141 mg/dL, 71-113 mg/dL) on the biochemical panel.

An endoscopic tracheal wash and blind bronchoalveolar lavage were performed and submitted for cytologic evaluation.

Evaluate the representative photomicrographs of the direct smear of the tracheal wash and answer the questions posed below:

  1. What cell types are present in the smears (how would you characterize the results)?
  2. What are your differential diagnoses for the findings?


Figure 1: Tracheal wash from a horse (10x objective)


Figure 2: Tracheal wash from a horse (50x objective)

Answer on next page

Dec 012016

Joint aspirate from a tortoise

Case information:

An approximately 18 month old, male Hermann’s tortoise presented for raspy breathing, exuberant, pink tissue over the eyes and being less active than normal. On physical examination the tortoise was small for his age, had increased respiratory rate and effort, was 5% dehydrated and would not open his eyes. While the tortoise was fully ambulatory, his left rear leg was swollen in the tarsal region. Whole body radiographs were taken to better assess the animal’s overall health. No abnormalities were seen in the lungs, but extensive bone loss and soft tissue swelling was noted in the region of the left tarsus. The left tarsal joint was aspirated and thick, gritty material was obtained. A portion of this sample was submitted for culture, while the remainder of the sample was assessed cytologically. Evaluate the photomicrographs of the submitted joint material and consider the following questions:


  1. What types of inflammatory cells are present?
  2. What are the structures indicated by the arrows in Figure 3 (also pictured in Figure 1A)?
  3. What is the final diagnosis based on the cytological findings?

Figure 1A. Left tarsus joint aspirate from a tortoise (Wright's stain 500x)

Figure 1A. Left tarsus joint aspirate from a tortoise (Wright’s stain 500x)

Figure 2A. Left tarsus joint aspirate from a tortoise (Wright's stain 500x)

Figure 2A. Left tarsus joint aspirate from a tortoise (Wright’s stain 500x)

Figure 3A. Left tarsus joint aspirate from a tortoise (Wright's stain 1000x)

Figure 3A. Left tarsus joint aspirate from a tortoise (Wright’s stain 1000x)

Answers are on the next page

Nov 012016

Biochemical results from a vomiting dog

Case information:

A 2 year-old male castrated Cane Corso presented to the Cornell University Hospital for Animals for a two-day history of vomiting, hypoglycemia, and bradycardia. Blood-work performed at the referring veterinarian revealed a hyponatremia and hyperkalemia. No abnormalities were found on abdominal radiographs. Prior to referring the dog to the Cornell Emergency service, the rDVM began treatment with a bolus of 50% dextrose and 0.9% NaCl. The dog had a previous history of hospitalization for sepsis, vomiting, and diarrhea that had occurred one week after vaccination for rabies and distemper. Consequently, all vaccine protocols were discontinued and were therefore not up-to-date.

On presentation, the dog was quiet but alert, and hypothermic at 97.3ºF. The remainder of the physical examination was within normal limits. The dog was started on intravenous fluids supplemented with glucose. Rapid in-house assessment tests, venous blood gas analysis, complete blood count, and a full serum chemistry panel were performed. Fluids, supplemented with dextrose, were continued overnight and a constant rate infusion of hydrocortisone was started. A free catch urine and stool sample were also submitted for evaluation.

Review the laboratory data provided, and answer the following interpretive questions. (Abnormal and pertinent laboratory data have been included. Test results not included were within reference intervals.)


Chemistry panel

Blood gases



  1. Given the dog’s clinical history and presentation, what is an unexpected finding in the hemogram results?
  2. What are the differential diagnoses for hypocholesterolemia and which is the most likely in this case?
  3. Presuming the dog’s azotemia resolves with fluid therapy, how would you explain the reduced concentrating ability of the kidney?

Answers are on the next page

Oct 012016

Conjunctival swab from a cat

Case information

A 6 year old male castrated domestic shorthair cat presented to the Cornell University Hospital for Animals (CUHA) emergency service for evaluation of worsening eye pain and inappetance. The cat was previously seen by the ophthalmology service at CUHA one week prior for evaluation of ocular discharge and conjunctival swelling of the left eye. In the latter examination, there was no evidence of penetrating trauma or foreign body. The cat was diagnosed with conjunctivitis and discharged with erythromycin ophthalmic ointment q 8 hours.

Upon presentation to the emergency service, the cat demonstrated blepharospasm in both eyes. No other physical examination abnormalities were noted. A CBC and serum chemistry panel were performed and were largely unremarkable. A swab of the conjunctiva was performed and applied to a slide for cytologic evaluation. Representative images from the Wright’s stained smears are provided.

Evaluate the provided images below and answer the following questions:

  1. What type of inflammation is present? 
  2. Can you identify the cause of the inflammation? 
  3. What additional diagnostic could be performed to confirm the cytologic diagnosis? 

Figure 1: Conjunctival swab from a cat

Figure 1: Conjunctival swab from a cat

Figure 2: Conjunctival swab from a cat

Figure 2: Conjunctival swab from a cat

Figure 3: Conjunctival swab from a cat

Figure 3: Conjunctival swab from a cat

Figure 4: Conjunctival swab from a cat

Figure 4: Conjunctival swab from a cat

Answer on next page