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!).
An 11-month-old Thoroughbred filly presented to the Cornell University Hospital for Animals with a 10 day history of persistent lethargy, intermittent fever, diarrhea and hypodipsia. There was no response to antibiotics and fluids administered by the referring veterinarian.
On physical examination, the filly was quiet, alert and responsive, but in poor condition with a distended “pot-bellied” abdomen and dehydration. Mucous membranes of the oral and vaginal mucosa were hyperemic and the capillary refill time was 3 seconds. There were decreased borborygmi on abdominal auscultation. The filly had high heart and respiratory rates, with increased bronchovesicular sounds, and was afebrile.
Ultrasonographic examination of the thorax and abdomen revealed mild pleural roughening and a markedly enlarged liver that was comprised of several large or multiple coalescing masses, with intraluminal material in portal and splenic veins (suspected thrombosis). A 21 x 25 cm complex mass with a liquid center was noted in the cranial part of the abdomen. Thoracic radiographs did not reveal any abnormalities. Point-of-care testing revealed a packed cell volume of 64% and total protein by refractometer of 8.4 g/dL.
The filly was administered a bolus of 15 liters of intravenous fluids and then was treated with antibiotics and intravenous fluids overnight. The next day, blood was sampled for hematologic and biochemical testing (Tables 1 and 2) and a screening coagulation panel. Coagulation testing revealed a prolonged prothrombin time (27 seconds, reference interval 16-20 seconds) with a normal activated partial thromboplastin time (59 seconds, reference interval 45-66 seconds) and hyperfibrinogenemia (1131 mg/dL, reference interval 175-445 mg/dL). Bile acid testing revealed a high normal concentration (11 μmol/L, reference interval 0-11 μmol/L).
Table 1: Pertinent hematologic results
White blood cells
Total protein by refractometer
Table 2: Pertinent biochemical results
The hepatic mass was biopsied under ultrasonographic guidance and scrapings were made from the submitted tissue, smeared onto slides and stained with modified Wright’s stain. Examine the representative images of the smears, then answer the questions below:
Do most of the cells in the aspirate have features typical of mature hepatocytes?
What is your cytologic diagnosis, incorporating all observed cytologic findings?
Does this diagnosis provide pathophysiologic mechanisms that would explain some of the hematologic and biochemical findings?
A 12 year old male, neutered domestic shorthair cat was presented to the Cornell University Hospital for Animals (CUHA) for an acute onset of paraplegia involving both distal limbs and difficulty breathing. The cat was up to date on all vaccinations. The complete biochemistry panel and blood gas results are shown below:
Biochemistry panel and blood gas results:
What major organ systems are affected in this cat and what do you think is the cause of the parapalegia?
Describe and interpret the cat’s acid base status.
What disease process is the cat at a major risk of developing (if he has not already)?
A 13-yr old female spayed domestic longhair cat presented to the oncology service at Cornell University Hospital for Animals for a renal tumor. The cat presented to the regular veterinarian with a 2-week history of progressive hyporexia, suspected weight loss and intermittent vomiting. On physical examination by regular veterinarian, the cat was noted to have bilateral renal enlargement, hypercalcemia and azotemia. At that time, renal neoplasia was discussed and supportive care was provided. Vomiting resolved with supportive care, but the cat continued to be progressively anorectic and continued to lose weight.
On presentation to Cornell, the cat’s temperature, respiration and heart rate were within normal limits. The cat was quiet, but alert and responsive, with a body condition score of 3/9 (cachectic). On abdominal palpation the right and left kidneys were moderately and mildly enlarged, respectively. A complete blood count revealed a mild normocytic normochromic non-regenerative anemia (RBC 6.5 mill/uL [reference interval 6.9-10.1 mill/uL]; MCV 48 fL [reference interval 40 – 52 fL]; MCHC 33 g/dL [reference interval 32 – 35 g/dL]), consistent with anemia of chronic disease, and a moderate thrombocytopenia (92 thou/uL [reference interval 195-624 thou/uL]). Serum biochemical testing revealed a moderate azotemia (urea nitrogen 74 mg/dL [reference interval 16 – 36 mg/dL]; creatinine 1.8 mg/dL [reference interval 0.6 – 2.0 mg/dL]) interpreted as a renal azotemia, moderate hypercalcemia (16.4 mg/dL [reference interval 9.1-10.9 mg/dL]) with a moderate increase in ionized calcium (2.25 mmol/L [reference interval 1.11-1.38 mmol/L] with a concurrent mild hypophosphatemia (2.6 mg/dL [reference interval 2.7-6.2 mg/dL]), mild proportional hyponatremia and hypochloremia (sodium 150 mEq/L [reference interval 151 – 158 mEq/L]; chloride 112 mEq/L [reference interval 113 – 123 mEq/L]), interpreted as fluid losses (likely renal) with water replenishment through drinking. There was mild evidence of muscle injury (creatine kinase 735 U/L [reference interval 73 – 388 U/L] and AST 65 U/L [reference interval 15 – 44 U/L]). Concurrent liver injury could not be ruled out, particularly as the cat had very mildly alkaline phosphatase activity (85 U/L [reference interval 13 – 83 U/L]).
Abdominal ultrasound revealed a mass in the right kidney and extending into renal vessels, that was lobulated and heterogeneous. A fine needle aspirate of the mass was performed. Evaluate the photomicrographs of the fine needle aspirate and answer the following questions:
Figure 1A: Fine needle aspirate of a renal mass (Wrights stain 20x)
Figure 1B: Fine needle aspirate of a renal mass (Wright’s stain 20x)
Figure 1C: Fine needle aspirate of a renal mass (Wright’s stain 50x)
What uncommon findings are present in the fine needle aspirate of the renal mass?
How would the hypercalcemia be explained in this case?
A 5 year old Thoroughbred-paint gelding presented to the Cornell University Large Animal Hospital with a history of increased respiratory effort, abdominal distention, and depression after turn out to a new pasture. On presentation, the horse was quiet, alert and responsive, and vital signs were within normal limits. Physical examination revealed abdominal distention and pain, decreased intestinal sounds, and abnormal rectal palpation (absence of fecal material, distended cecum, and dilated loops of small intestine). Due to the marked abdominal distention, the cecum was trocharized and some of the gas distention was relieved. The horse was treated with intravenous fluids and 2% lidocaine (250 mL as a constant rate infusion) for pain control and monitored overnight. The day after initial presentation, the horse’s condition had improved and rectal examination revealed normal formed manure and decreased colon distention. The lidocaine infusion was discontinued. On the second day of hospitalization, blood and peritoneal fluid were collected and submitted for a complete blood count and biochemical analysis, and cytologic evaluation, respectively.
Blood work revealed a mild non-regenerative anemia with a hematocrit of 32% (reference interval [RI], 34-46%) interpreted as decreased erythropoiesis in response to inflammation. There was an inflammatory leukogram due to the presence of a mild left shift (0.3 thousand/µL; RI, 0.0-0.1 thousand/µL), and mild toxic change, despite normal total leukocyte (5.5 thousand/µL; RI, 5.2-10.1 thousand/µL) and neutrophil (4.6 thousand/µL; RI, 2.4-6.6 thousand/µL) counts. There was a mild lymphopenia of 0.6 thousand/µL (RI, 1.2-4.9 thousand/µL) supporting concurrent stress (glucocorticoid response). Biochemical results were overall unremarkable.
The submitted peritoneal fluid was light-orange in color and opaque, with a total protein by refractometry of 5.5 g/dL (upper reference limit, <2.5 g/dL). The total nucleated cell count was 1004.6 thousand/µL (RI, <5.0 thousand/µL) and the red blood cell count was 314.2 thousand/µL. Direct smears from the submitted fluid were prepared and examined.
Evaluate the representative photomicrographs of the peritoneal fluid shown below and answer the following questions:
Identify the cells labeled as “A” and “B” in Figure 3.
How would you classify the effusion? Can you identify a cause?
What do you think the prognosis would be for this horse?
Figure 1. Peritoneal fluid from a horse (Wright’s stain, 20x objective)
Figure 2. Peritoneal fluid from a horse (Wright’s stain, 50x objective)
Figure 3. Peritoneal fluid from a horse (Wright’s stain, 100x objective)
Figure 4. Peritoneal fluid from a horse (Wright’s stain, 100x objective)
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
Moderate rouleaux formation
Table 2: Chemistry, serum
What does rouleaux formation of red blood cells (RBCs) indicate?
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?
What pathologic processes can be identified based on the provided chemistry results? What are your differential diagnoses and what diagnostic test would you recommend?
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
* Mixture of indirect and direct bilirubin
Table 2: Pertinent urinalysis results
Urine specific gravity
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:
How would you interpret the changes in the biochemical panel?
Is a cause for these changes evident in the liver aspirate?
What is going on in the kidney and how do you explain the renal-related results?
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.
Which lesion is likely the primary site?
If the third eyelid mass was not present, how would this change the differential diagnosis list?
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
For which cell line is the analyzer clearly reporting spuriously decreased results?
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?
How would you classify the large cells in Figures 2-3?
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)
Serum Chemistry Panel
How would you interpret the leukogram?
What type of acid-base disturbance(s) can you identify from the serum chemistry panel?
What other diagnostic tests should be performed in this case?
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:
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:
What type of metabolic derangement is present?
Identify and evaluate the cells labeled as “A” and “B” in Figure 2.
What additional diagnostic tests would you do in this case?
Figure 1. Peritoneal fluid from an alpaca (Wright’s stain, 20x objective)
Figure 2. Peritoneal fluid from an alpaca (Wright’s stain, 50x objective)
Figure 3. Peritoneal fluid from an alpaca (Wright’s stain, 100x objective)
Figure 4. Peritoneal fluid from an alpaca (Gram stain, 100x objective)