Jan 012000
 

In our diagnostic challenges, 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 1-2 months. 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 the diagnostic challenges (yet!).

Dec 072019
 

Mass on the left hind foot of a cat

Case information

A fine needle aspirate was obtained from a mass lesion on the left hind foot of a nine year old male castrated domestic longhair cat. Smears of the aspirate were submitted to the Animal Health Diagnostic Center at Cornell University for examination. The mass was located over the lateral aspect of the metatarsophalangeal joint. The mass was first noted approximately 2.5 months before sampling. At that time, the owner reported a “pea-sized” mass on the lateral aspect of the paw. The mass grew slowly over the next several weeks and measured 2.3 x 1.4 cm at the time of sampling. The mass was described as a rounded, raised, poorly haired to alopecic, soft to slightly firm, movable, non-painful mass with no deep attachments. The patient did not appear to be bothered by the lesion. The mass was non-painful on physical examination and no lameness or altered grooming behavior were reported.

Examine the provided images from the aspirate of the mass, then answer the following questions:

  1. What general lineage would you assign to these cells?  
  2. What are your differential diagnoses for the mass?

 

Figure 1: Photomicrograph of a mass on the foot of a cat (with calipers)

Figure 2: Aspirate of a foot mass in a cat (Wright’s stain, 100x objective)

Figure 3: Aspirate of a foot mass in a cat (Wright’s stain, 50x objective)

Figure 4: Aspirate of a foot mass in a cat (Wright’s stain, 50x objective)

 

Figure 5: Aspirate of a foot mass in a cat (Wright’s stain, 100x objective)

Answers on the next page

Nov 142019
 

Pleural fluid from a horse

 

Case Information

A 19 year old Arabian stallion presented for evaluation for the cause of a pleural effusion. A large amount of pleural fluid was identified on thoracic ultrasonographic examination and the fluid was sampled for analysis. The fluid was dark yellow in color and slightly cloudy. Cell counts were low (800 nucleated cells/μL) with a small amount of blood (15.2 thousand RBCs/μL). Total protein by refractometry was mildly increased at 2.7 g/dL. Cytospin preparations of the fluid were prepared for cytological evaluation and were stained with a modified Wright’s stain.

Examine the provided images of the pleural fluid, then answer the following questions:

  1. How would you classify this effusion as to mechanism of formation?
  2. What other stains might you consider applying to this sample?
  3. What is your cytologic diagnosis?

Figure 1: Pleural fluid from a horse (Wright’s stain, 10x objective)

Figure 2: Pleural fluid from a horse (Wright’s stain, 50x objective)

Figure 3: Pleural fluid from a horse (Wright’s stain, 100x objective)

Figure 4: Pleural fluid from a horse (Wright’s stain, 100x objective)

 

Figure 5: Pleural fluid from a horse (Wright’s stain, 100x objective)

Answers on the next page

Oct 152019
 

Bone marrow aspirate from a horse with hyperglobulinemia

 

Case Information

A 22-year-old Thoroughbred gelding presented for an approximately 3-week history of neurologic signs and neck stiffness. In addition, the horse was described to be pancytopenic and hyperproteinemic (8.3 g/dL; reference interval [RI]: 5.6 – 7.9 g/dL), due to a mild to moderate hyperglobulinemia (5.5 g/dL; RI: 2.4 – 4.7 g/dL). The albumin concentration was within the reference interval (2.9 g/dL; RI: 1.9 – 3.2 g/dL). The pancytopenia was characterized by a mild anemia (HCT: 22 %; RI: 30.0 – 47.0 %), leukopenia (3.7 K/μL; RI: 4.9 – 11.1 K/μL) due to a neutropenia (2.4 K/μL; RI: 2.5 – 6.9 K/μL) and moderate thrombocytopenia (49 K/μL; RI: 100 – 250 K/μL).

Upon re-examination by the veterinarian, a repeat complete blood count (CBC) was performed and results were as follows (Table 1):

Given the CBC findings, a bone marrow aspirate and core biopsy was performed and submitted to the Animal Health Diagnostic Center (AHDC) at Cornell University. Direct smears of the freshly collected marrow were also prepared and submitted along with an EDTA-anticoagulated marrow sample.

Provided below re representative images of the bone marrow aspirate.

Figure 1: Bone marrow aspirate from a horse, 10x Wright’s stain.

Figure 2: Bone marrow aspirate from a horse, 50x Wright’s stain.

Figure 3: Bone marrow aspirate from a horse, 100x Wright’s stain.

Using the provided information, answer the following questions:

  1. What is the main mechanism for the persistent anemia in this horse?
  2. Which is the predominant cell population in the provided images?
  3. What additional test would you recommend?

Answers on the next page.

Aug 152019
 

Liver aspirate from a 2 year old cat

 

Case Information

A 2 year old spayed female domestic longhair cat presented for evaluation of chronic upper respiratory disease. The cat was depressed but not inappetent. Increased activities of alanine aminotransferase (ALT, 966 U/L, reference interval, 28-109 U/L)  and alkaline phosphatase (ALP, 111 U/L, reference interval, 11-49 U/L) were noted on a screening biochemical panel. The cat also had a high total bilirubin concentration (0.7 mg/dL, reference interval, 0-0.1 mg/dL). Abdominal ultrasonographic examination showed a diffusely coarse liver and a hyperechoic gall bladder wall (inflammation, presumptive). A liver aspirate was taken and submitted to the Animal Health Diagnostic Center at Cornell University for examination.

Examine the provided images from the liver aspirate, then answer the following questions:

  1. What abnormalities can you identify in the aspirate?
  2. What additional tests are indicated?

Figure 1: Liver aspirate (Diff-quik, 100x objective)

Figure 2: Liver aspirate (Wright’s stain, 100x objective)

Figure 3: Liver aspirate (Wright’s stain, 100x objective)

Answers on the next page

Jun 102019
 

Peritoneal fluid from a goat

Case information

An 8 year old female goat was presented to the Cornell University Farm Animal Hospital for a 10 day history of lethargy and dullness. The goat was also intermittently febrile with temperatures as high as 104.8F. Treatments of Banamine, calcium, and vitamin B complex on the farm resulted in minimal improvement.

On presentation to Cornell, the goat was quiet, alert, and responsive. The animal demonstrated periods of dullness and shaking, particularly of the head. Vital signs were slightly abnormal (temperature: 102.3F, pulse: 110 bpm, and respiration: 42 bpm). Point of care bloodwork revealed a mildly increased lactate concentration. Abdominal ultrasonographic examination revealed severe peritoneal effusion and an abnormal/hyperechoic gastrointestinal tract. Initial empiric treatments included intravenous fluids, antibiotics, thiamine, and vitamin B. An abdominocentesis was performed to submit a sample for cytology and fluid analysis.

The fluid was light yellow and slightly cloudy. Total protein by refractometry was <2.5 g/dL. Direct smears were prepared from the submitted fluid. In addition, a squash preparation was made from visible “clots” in the fluid. Representative images from the latter are provided below.

Examine the provided images, and answer the following questions:

  1. What cells can you identify? 
  2. What is your cytologic interpretation of the effusion? 
  3. What are your differential diagnoses?

Figure 1

Figure 1: Peritoneal fluid from a goat (Wright’s stain, 10x objective)

Figure 2

Figure 2: Peritoneal fluid from a goat (Wright’s stain, 20x objective)

Figure 3

Figure 3: Peritoneal fluid from a goat (Wright’s stain, 50x objective)

Figure 4

Figure 4: Peritoneal fluid from a goat (Wright’s stain, 100x objective)

Figure 5

Figure 5: Peritoneal fluid from a goat (Wright’s stain, 100x objective)

 

Answer on next page


May 182019
 

Pleural fluid from a 2 year old dog

 

Case Information

Computerized tomography image of the mass

Figure 2: Abdominal CT

Ultrasound of challenge #5

Figure 1: Abdominal US

A 2 year old intact female mixed breed dog presented for evaluation of a bicavitory (pleural and peritoneal) effusion after showing mildly reduced activity. The dog was clinically healthy up until this time but had suffered from abnormal heats (increased frequency, prolonged, split heats). Routine hemogram, biochemical and coagulation testing did not reveal any abnormalities. On abdominal ultrasonographic examination, the uterus was enlarged and dilated and a 5.8 x 4.6 cm mass was noted next to the right cranial uterine horn (Figure 1). The left ovary was normal in appearance. Computerized tomography of the abdomen and thorax revealed a large amount of peritoneal and pleural fluid. A large cavitated nodular mass (10 x 11 x 14 cm, Figure 2), contiguous with the dilated right uterine horn, was seen caudal to the right kidney and mesenteric lymph nodes were enlarged. There was a concurrent nodular spiral pattern in the omentum. In the thorax, a large mass (6 x 9 x 9 cm) was noted in the left mediastinum, along with a focal alveolar infiltrate in the right cranial lung lobe and enlarged sternal lymph nodes.  The pleural fluid was aspirated and mailed into the Animal Health Diagnostic Center for cytologic examination (a direct smear was also provided with the fluid). The fluid was medium red and opaque, with a total nucleated cell count of 10,300/μL, red blood cell count of 234,000/μL and a total protein by refractometer of 2.7 g/dL. Sediment smears were prepared from the fluid and stained with modified Wright’s stain. 

Examine the provided images from the stained sediment smears of the fluid, then answer the following questions:

  1. What cells can you identify in the smears?
  2. What is your cytologic diagnosis?
  3. How do you relate these findings to the identified abdominal mass? 

DC5_2019Fig1

Figure 3: Pleural fluid from a 2 year old dog with bicavitory effusion (50x, Wright’s stain)

DC5_2019Fig2

Figure 4: Pleural fluid from a 2 year old dog with bicavitory effusion (50x, Wright’s stain)

DC5_2019Fig3

Figure 5: Pleural fluid from a 2 year old dog with bicavitory effusion (50x, Wright’s stain)

DC5_2019Fig4

Figure 6: Pleural fluid from a 2 year old dog with bicavitory effusion (50x, Wright’s stain)

Answers on the next page

Apr 102019
 

Bone marrow from a dog

Case information

A 3-year-old spayed female Golden Retriever was presented to Cornell University Animal Hospital’s (CUHA) Internal Medicine Department for evaluation of lethargy and pancytopenia. The patient had displayed intermittent lethargy for approximately one month prior to presentation with one episode of collapse for which the dog had been presented by the owner to the primary care veterinarian. Physical examination at that time revealed a mild fever of 102.9°F but was otherwise unremarkable. Routine laboratory tests demonstrated a pancytopenia, hypoalbuminemia and hypocholesterolemia. A resting cortisol was performed and was within reference intervals, excluding hypoadrenocorticism. A tick-borne disease panel was negative except for a positive polymerase chain reaction result for Lyme disease.  Leptospira antibody titers were also negative. A course of doxycycline was instituted but there was minimal improvement in the dog’s demeanor or laboratory results. As a result, the was referred to CUHA. The patient was up to date with vaccinations and was receiving routine heartworm, flea and tick preventatives.

Upon physical examination, the patient was mildly febrile with a temperature of 102.8°F and had mild lymphadenopathy of the prescapular and right popliteal lymph nodes, in addition to a few petechaie under the tongue. Otherwise, the rest of the physical examination was unremarkable.

A complete blood count (CBC) and chemistry panel were submitted. The CBC revealed a nonregenerative normocytic normochromic anemia (hematocrit 16%; reference interval [RI], 41-58%), leukopenia (leukocytes 3.3 thous/µL; RI 5.7-14.2 thous/µL) due primarily to a severe neutropenia (0.6 thous/µL; RI 2.7-9.4 thous/µL), and profound thrombocytopenia (7 thous/µL; RI 186-545 thous/µL). The chemistry panel demonstrated mild hypoalbuminemia (2.9 g/dL; RI 3.2-4.1 g/dL) and moderate to marked hypocholesterolemia (57 mg/dL; RI 136-392 g/dL) along with some other minor, clinically insignificant abnormalities. Urinalysis was unremarkable with a urine specific gravity of 1.024. Due to the low hematocrit, blood typing was performed and a packed red cell transfusion administered. Thoracic radiographs were unremarkable and abdominal ultrasonography revealed mild uniform splenomegaly. The patient was sedated and a bone marrow aspiration performed. Representative cytologic images from the bone marrow are shown below.

Figure 1. Bone marrow aspirate from a pancytopenic dog (Wright’s stain, 50x objective).

Figure 2. Bone marrow aspirate from a pancytopenic dog (Wright’s stain, 100x objective).

Figure 3. Bone marrow aspirate from a pancytopenic dog (Wright’s stain, 100x objective).

Using the provided information, answer the following questions;

  1. What are your differential diagnoses for the cells labeled with the arrows?
  2. What additional diagnostic tests would you recommend to elucidate the cell of origin?
  3. What are your proposed mechanisms for the biochemical abnormalities?

Answers are provided on the next page.

Mar 072019
 

Facial mass on a goat

Case information

A 7-year-old male Nigerian Dwarf Goat presented with a mass on the left cheek. The owner reported the mass had been present for about two years, but had recently begun to increase in size. The lesion was described as a 2 cm round dermal mass. A fine needle aspirate of the mass was performed and smears were submitted to the Animal Health Diagnostic Center (AHDC) at Cornell University. The slides were stained in the laboratory and representative images are provided below.

Provided below are representative images of the fine needle aspirate.

Figure 1: Left cheek mass in a goat (Wright’s stain, 10x objective)

Figure 2: Left cheek mass in a goat (Wright’s stain, 50x objective)

Figure 3: Left cheek mass in a goat (Wright’s stain, 50x objective)

Figure 4: Left cheek mass in a goat (Wright’s stain, 100x objective)

Using the provided information, answer the following questions;

  1. What are your differential diagnoses for the pink background material in the images?
  2. What term is used to describe the arrangement of the red blood cells in this sample?
  3. What cellular features can be used to narrow down the differential diagnostic list?

Answers are provided on the next page.

Feb 012019
 

Synovial fluid from a horse

Case Information

A 13 year old Draft mix gelding presented with a 2 week history of left front limb lameness. On physical examination, there was moderate joint effusion of the fetlock joint.

Synovial fluid was aseptically collected into a plain red top tube (without anticoagulant) and a purple top tube (with EDTA anticoagulant) and submitted for fluid analysis and culture to the Animal Health Diagnostic Center (AHDC) at Cornell University. Prior to submission, direct smears from the freshly collected fluid were made and submitted along with the fluid. The results of the fluid analysis are provided below.

Provided below are representative images of the joint fluid.

Figure 1: Synovial fluid from a horse (Wright’s stain, 20x objective)

Figure 2: Synovial fluid from a horse (Wright’s stain, 50x; inset, 100x)

Figure 3: Synovial fluid from a horse (Wright’s stain, 100x objective)

Using the provided information, answer the following questions;

  1. What are the cell populations in the fluid and which population is dominating?
  2. How would you interpret the joint fluid based on the nucleated cell count, total protein concentration and the provided images?
  3. What would be your differential diagnoses?

Answers on the next page.

Jan 012019
 

Peripheral blood from a cat

 

Case Information

A 1 year-old, female spayed, Domestic Short Hair cat presented to the primary veterinarian after being missing outside for 3 weeks.  The cat was lethargic, inappetent, and had a painful left hind limb along with pale mucous membranes, and a temperature of 94.6ºF.  In-house bloodwork revealed a severe anemia (hematocrit, 9%).  The patient was stabilized and then referred to the Cornell University Hospital for Animals Emergency and Critical Care department for a blood transfusion.  Upon presentation, the patient was quiet, alert, and responsive, had generalized flea dirt, an abscess on the medial aspect of the left hock, pale mucous membranes, weak pulses, and an increased respiratory rate.  The patient was initially stabilized and a complete blood count was sent to the Clinical Pathology laboratory the next day.  A complete blood count (CBC) revealed a severe anemia (hematocrit 12%, reference interval 31-48%) with a moderate inflammatory leukogram, including a moderate neutrophilia (20.3 thou/μL, reference interval 2.3-11.6 thou/μL) with a mild left shift (1.7 thou/μL, reference interval 0.0-0.1 thou/μL) and mild toxic change, and a moderate thrombocytopenia (100 thou/μL, reference interval 195-624 thou/μL).  A blood smear was also evaluated as part of the CBC.

After viewing the figures of the blood smear below, answer the provided questions.

  1. What red blood cell morphologic changes can you glean from these images?
  2. Based on the red blood cell changes, what is the mechanism of the anemia in this cat?
  3. Can you identify a cause of the anemia?

Jan2018COM_Fig1

Figure 1: Blood smear from a cat (Wright’s stain, 50x objective)

Jan2018COM_Fig2

Figure 2: Blood smear from a cat (Wright’s stain 100x objective)

Answers on the next page

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