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!).
A 1-year-old intact male dog was presented on an emergency basis to the Cornell University Hospital for Animals (CUHA) after a blunt traumatic episode. The dog was quiet, alert and responsive upon physical examination. Multiple cutaneous abrasions were noted around the right hind leg and inguinal region. The mucous membranes were tacky and pale pink. The dog was tachycardic (190 beats per minute) and no overt murmurs or arrhythmias were auscultated. Decreased bronchovesicular sounds were auscultated bilaterally, but there were no crackles or wheezes. The dog was ambulatory in the front legs with paraparesis of the hind legs due to multiple pelvic fractures, which were confirmed on lateral and ventrodorsal radiographs. There was a bloody preputial discharge and hematuria.
Abbreviated blood work performed in-house revealed a mild hyperglycemia (136 mg/dL; reference interval [RI]: 60 – 120 mg/dL) and hyperlactatemia (4.4 mmol/L; RI: < 2.0 mmol/La) with a normal hematocrit (45%; RI: 41 – 58%) and total solids (7.2 g/dL; RI: 5.9 – 7.8 g/dL). Initial abdominal FAST scan ultrasound showed no abnormalities. A repeat heparinized plasma biochemical analysis, performed after treatment and fluid therapy, showed a persistent hyperglycemia (167 mg/dL; RI: 68 – 104 mg/dL) and mild increases in aspartate aminotransferase (AST: 103 U/L; RI: 18 – 56 U/L) and creatine kinase (CK: 3760 U/L; RI: 64 – 314 U/L) activities. There were no evidence of azotemia (urea nitrogen: 21 mg/dL [RI: 9 – 26 mg/dL]; creatinine: 0.8 mg/dL [RI: 0.6 – 1.4 mg/dL]). Approximately 15-hours post-hospitalization, there was a small amount of abdominal fluid. The fluid was aspirated into an EDTA (purple top) tube and submitted to the laboratory for peritoneal fluid analysis.
Provided are the results and representative images from direct and cytospin smears of the peritoneal fluid.
Figure 1: Peritoneal fluid from a dog, direct smear, 20x, Wright’s stain.
Figure 2: Peritoneal fluid from a dog, cytospin smear, 50x, Wright’s stain.
Figure 3: Peritoneal fluid from a dog, cytospin smear, 100x, Wright’s stain.
Using the provided information answer the following questions,
What is the predominant cell population in the sample?
What is your cytologic diagnosis?
What additional test could be considered to further support your diagnosis?
Answers on the next page.
a: Mathews, K.A. (2012). ‘Monitoring Fluid Therapy and Complications of Fluid Therapy’, in DiBartola, S.P. Fluid, Electrolyte, and Acid-Base Disorders in Small Animal Practice. St. Louis, Missouri: Saunders Elsevier Inc. pp:386–404.
An 8 year old male neutered domestic shorthair cat was presented to an emergency hospital with a 4 day history of vomiting and inappetence. The vomiting was partially responsive to Cerenia® (Maropitant). The owner had also noticed purple mucous membranes. The cat was an indoor cat and may have had access to the bathroom cabinet. On physical examination, the cat had cyanotic mucous membranes, and was hypothermic (97.7ºF), equivocally tachycardic (the heart rate was at upper end of normal limits at 220 beats/minute) and panting (respiratory rate of 100 breaths per minute). A venous blood sample was taken for an automated hemogram and biochemical profile and was observed to be brown. Results are shown below (Figures 1-3).
Figure 1: Hemogram
Figure 2: Automated dotplots
Figure 3: Biochemical panel
The blood was then sent to the Animal Health Diagnostic Laboratory for a blood smear examination and was received 5 days after collection. Examine the images of the Wright’s-stained smear then answer the posed questions.
What abnormalities are evident in the blood smear?
What additional stain can be applied to confirm your observation?
Given the history, what is the likely diagnosis?
What additional testing would you consider?
How would you treat the cat?
Figure 4: Venous blood from a cat (Wright’s stain, 20x)
Figure 5: Venous blood from a cat (Wright’s stain, 100x)
Figure 6: Venous blood from a cat (Wright’s stain, 100x)
A 9 year-old, neutered male American pit bull terrier presented to a private veterinary practice for re-evaluation of a swelling within the interdigital space of P3 and P4 on the left front paw. The swelling was noted 6 weeks before, at which time it was oozing a hemorrhagic, purulent material. The swelling was initially thought to be an interdigital cyst and was treated with an course of antibiotics and a tapering dose of prednisone. The swelling seemed to shrink with treatment but did not resolve completely. At the re-evaluation, the veterinarian performed a fine needle aspirate of the swelling and submitted the smears of the aspirate to the Animal Health Diagnostic Center at Cornell University for examination. Examine the image from the smears below, then answer these questions:
What broad category of tissue cells are present in the sample?
Based on your answer for question 1, what would be your top differential diagnosis for the cause of the mass?
What additional finding is evident in the smears that supports your answer to question 2?
Figure 1: Aspirate of an interdigital swelling (Wright’s stain, 20x objective)
Figure 2: Aspirate of an interdigital swelling (Wright’s stain, 50x objective)
Figure 3: Aspirate of an interdigital swelling (Wright’s stain, 50x objective)
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:
What general lineage would you assign to these cells?
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)
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:
How would you classify this effusion as to mechanism of formation?
What other stains might you consider applying to this sample?
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)
Bone marrow aspirate from a horse with hyperglobulinemia
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:
What is the main mechanism for the persistent anemia in this horse?
Which is the predominant cell population in the provided images?
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:
What abnormalities can you identify in the aspirate?
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:
What cells can you identify?
What is your cytologic interpretation of the effusion?
What are your differential diagnoses?
Figure 1: Peritoneal fluid from a goat (Wright’s stain, 10x objective)
Figure 2: Peritoneal fluid from a goat (Wright’s stain, 20x objective)
Figure 3: Peritoneal fluid from a goat (Wright’s stain, 50x objective)
Figure 4: Peritoneal fluid from a goat (Wright’s stain, 100x objective)
Figure 5: Peritoneal fluid from a goat (Wright’s stain, 100x objective)
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:
What cells can you identify in the smears?
What is your cytologic diagnosis?
How do you relate these findings to the identified abdominal mass?
Figure 3: Pleural fluid from a 2 year old dog with bicavitory effusion (50x, Wright’s stain)
Figure 4: Pleural fluid from a 2 year old dog with bicavitory effusion (50x, Wright’s stain)
Figure 5: Pleural fluid from a 2 year old dog with bicavitory effusion (50x, Wright’s stain)
Figure 6: Pleural fluid from a 2 year old dog with bicavitory effusion (50x, Wright’s stain)
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;
What are your differential diagnoses for the cells labeled with the arrows?
What additional diagnostic tests would you recommend to elucidate the cell of origin?
What are your proposed mechanisms for the biochemical abnormalities?