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!).
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;
What are the cell populations in the fluid and which population is dominating?
How would you interpret the joint fluid based on the nucleated cell count, total protein concentration and the provided images?
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.
What red blood cell morphologic changes can you glean from these images?
Based on the red blood cell changes, what is the mechanism of the anemia in this cat?
Can you identify a cause of the anemia?
Figure 1: Blood smear from a cat (Wright’s stain, 50x objective)
Figure 2: Blood smear from a cat (Wright’s stain 100x objective)
Aspirate from a cervical swelling in a Tokay gecko (Gecko gecko)
A captive 11 year old female Tokay gecko presented with a chronic (1 year) slowly progressive bilateral swelling of the upper cervical region (Figure 1). The swelling was more pronounced on the left side and had expanded more rapidly in the preceding 4 weeks. Other than size discrepancies, there were also differences noted between the two sides on palpation; the swelling was soft on the right side versus firm on the left side. Main findings on blood work were anemia (17% packed cell volume, average ÷ standard deviation reference value 30 ± 2% [n=6]1), hypercalcemia (48.4 mg/dL, average ÷ standard deviation reference value, 17.6 ± 0.4 mg/dL [n=2]1) and hypoalbuminemia (0.8 g/dL, reference animal [n=1], 2.7 g/dL1). On radiographs, both sides of the cervical region contained irregular mineralized opacities, however the left region also contained an enlarged diffuse soft tissue opacity with more irregular and lighter mineralized regions.2 The location of the mineralized areas on both sides was compatible with the endolymphatic sac. The swelling on the left cervical region was aspirated and yielded an opaque, white pink-tinged fluid. Removal of the fluid revealed a firm mass, which was also aspirated. Direct smears of the aspirated fluid and smears of the mass were examined and yielded similar cytologic findings (Figures 2-3).
Evaluate the provided cytologic images from the aspirated fluid, then answer the following questions:
What cells and structures can be identified in the direct smears of the aspirates?
What is your cytologic diagnosis?
Do the cytologic results explain the abnormalities in the hematologic and biochemical results?
Figure 1: Left cervical swelling in a captive Tokay gecko (gross)
Figure 2: Aspirate of a left cervical swelling in a gecko (10x)
Figure 3: Aspirate of a left cervical swelling in a gecko (50x)
A 1-year-old intact male English Mastiff was presented to Emergency Medicine at the Cornell University Hospital with a one week history of pollakiuria and stranguria. Four days prior to presentation, the dog had been started on oral prazocin (an α-1 adrenergic blocker) with no improvement. Hematuria, coughing, sneezing, or diarrhea were not reported. The patient had vomited food material and was inappetent in the 2 days prior to presentation. On physical examination, the patient was 5% dehydrated and was noted to be arching the lumbar spine. No abnormalities were noted on abdominal palpation. No abnormalities were detected on a hemogram and mild electrolyte changes (sodium 154 mEq/L, reference interval, 143-150 mEq/L; chloride 115 mEq/L, reference interval, 106-114 mEq/L) were evident on a biochemical panel. Abdominal radiographs were also obtained (Figure 1). Urine collected by cystocentesis was medium yellow, slightly cloudy with a urine specific gravity of 1.014, pH of 8.5, and trace protein on a dipstick. On urine sediment examination, moderate numbers of sperm and the crystals pictured below (Figures 2-3) were seen.
Evaluate the provided cytologic images (Figures 1-3) and answer the following questions:
What differential diagnosis would you have for this patient based on the history and imaging results?
What is your main differential diagnosis based on the crystalluria and what is unusual about the urinalysis in this case?
What additional treatment and tests would you recommend?
Figure 1: Left lateral caudal abdominal radiograph
A 7 year old castrated male mixed breed dog presented with a 9 month history of intermittent watery, mucoid and bloody diarrhea, which was not completely responsive to medical therapy and a hypoallergenic prescription diet. The patient subsequently developed panuveitis and was referred to Cornell University Hospital for Animals after starting treatment with prednisolone acetate eye drops and oral prednisone (5mg twice daily). Upon initial presentation, most of the physical examination was unremarkable, except there was still bilateral panuveitis, with 50 and 100% retinal detachment in the right and left eyes, respectively. A subretinal aspirate was performed of the left eye and submitted for cytologic evaluation.
Evaluate the provided cytologic images (Figures 1-3) and answer the following questions:
What differential diagnoses would you have for this patient based on the history?
What are the rod-like structures within the macrophages and scattered in the background?
What additional tests would you recommend?
Figure 1: Subretinal aspirate from a dog (Wright’s stain, 50x objective)
Figure 2: Subretinal aspirate from a dog (Wright’s stain, 100x objective)
Figure 3: Subretinal aspirate from a dog (Wright’s stain, 100x objective)
Aspirate from a subcutaneous mandibular mass in a cat
An 18 year old male neutered Domestic Shorthair cat presented to the Cornell University Hospital for Animals (CUHA) Emergency Service for evaluation of a subcutaneous left mandibular mass and inappetence. The mass had been previously incised by the primary veterinarian and had yielded purulent material. At that time, treatment with doxycycline was started, however the mass continued to increase in size. At the time of presentation to CUHA, the mass was approximately 2 x 2 x 0.5 cm, not painful on palpation, and not freely movable. Fine needle aspirates were taken from the mass for cytologic examination. Examine the representative images of the smears and answer the questions below:
What are the cells marked by the red and blue arrows in Figure 2?
What are your top differential diagnoses for the structures within the cells in Figures 3 and 4?
What additional testing would you recommend?
Figure 1: Aspirate of a left caudal mandibular mass from a cat (20x objective, Wright’s stain)
Figure 2: Aspirate of a left caudal mandibular mass from a cat (50x objective, Wright’s stain)
Figure 3: Aspirate of a left caudal mandibular mass from a cat (100x objective, Wright’s stain)
Figure 4: Aspirate of a left caudal mandibular mass from a cat (100x objective, Wright’s stain)
Aspirates from an abdominal and cutaneous mass in a dog
A neutered 8 year old Staffordshire Terrier mixed breed dog presented for re-evaluation of skin masses. Two subcutaneous (presumably ultraviolet light-induced) hemangiosarcomas had been surgically excised in the past. On examination, the dog had multiple red cutaneous lesions on the medial aspect of both hindlimbs and similar small lesions on the caudal abdomen. In addition, the dog had a subcutaneous mass on the right lateral distal hindlimb. Imaging for tumor staging revealed an abdominal mass cranial to the bladder. Aspirates were taken from two of the red cutaneous lesions (one on the right medial hind leg, one on the left medial hind leg), the subcutaneous mass on the right lateral distal hind leg and the abdominal mass. Examine the images of the smears from the right lateral distal hind leg and abdominal mass and answer the questions below.
What types of cells are found in the smears from each mass?
What is your cytologic diagnosis for each site?
Do you think the abdominal mass is related to the skin mass?
Figure 1: Aspirate of the right lateral distal hind leg mass (20x objective, Wright’s stain)
Figure 2: Aspirate of the abdominal mass (20x objective, Wright’s stain)
Figure 3: Aspirate of the abdominal mass (20x objective, Wright’s stain).
Figure 4: Aspirate of the abdominal mass (50x objective, Wright’s stain)
Cauliflower-like mass at the base of the penis of a dog
A 2-year-old castrated male mixed breed dog presented to the Cornell University Hospital for Animals (CUHA) Surgery Service for surgical revision of a previously amputated hind limb. The dog was rescued from the streets in Africa a few months prior and had partially amputated and infected right and left hindlimbs. The dog underwent a complete right hindlimb amputation with no complications. During post-operative care, a urinary catheter was placed and a 4.5cm x 3.4cm x 3.4cm cauliflower mass was observed at the base of the penis. The mass was friable, producing a mild serosanguinous discharge. Impression smears of the mass were taken and submitted to Clinical Pathology for microscopic examination.
Evaluate the provided representative images from the mass and answer the following questions:
What is the top differential diagnosis?
What is the significance of the other cells present?
What is the main route of “infection”?
Figure 1: Impression smears from a penile mass in a dog. Wright’s stain, 10x.
Figure 2: Impression smear from a penile mass in a dog. Wright’s stain, 50x.
Figure 3: Impression smear from a penile mass in a dog. Wright’s stain, 100x.
A 7 year old male castrated English Bulldog was presented to Cornell University Veterinary Specialists (CUVS) for further evaluation of an aggressive bone lesion. The dog initially presented to the referring veterinarian for a one week history of lameness. The dog was noted to be painful on palpation of the left elbow and shoulder. Radiographs of the left limb revealed an aggressive lesion in the proximal half of the left humeral diaphysis, distal to the metaphysis, characterized by indistinct / mottled intramedullary and cortical lysis with adjacent periosteal new bone formation on the caudal cortex. There was no apparent soft tissue swelling. Three-view thoracic radiographs were performed, and there was no evidence of metastatic disease. At CUVS, a fine needle aspirate was performed of the bone lesion and submitted for cytologic evaluation.
Evaluate the provided cytologic images and answer the following questions:
1. What are you differential diagnoses for the bone lesion based on the radiographic description?
2. Which of these differentials is favored given your cytologic interpretation?
3. What additional testing is recommended?
Figure 1: Fine needle aspirate of an aggressive bone lesion in a dog. (Wright’s stain, 20x objective)
Figure 2: Fine needle aspirate of an aggressive bone lesion in a dog.(Wright’s stain, 50x objective)
Figure 3: Fine needle aspirate of an aggressive bone lesion in a dog. (Diff-Quik stain, 100x objective)
Figure 4: Fine needle aspirate of an aggressive bone lesion in a dog. (Diff-Quik stain, 50x objective)
A Brown Swiss bull calf presented to Cornell University Equine Farm Animal Hospital for evaluation of a left humeral fracture. On presentation, the calf was obtunded, recumbent and unable to bear weight. The calf had a body condition score of 2/5 with severe muscle atrophy. Capillary refill time was approximately 2 seconds, but mucous membranes were noted to be pale pink. The heart rate and temperature were within normal limits, while the respiratory rate was 18 breaths per minute with bilateral cranioventral harsh lung sounds, increased respiratory effort and crackles.
Thoracic ultrasonographic and radiographic examination revealed severe bilateral cranioventral lung consolidation, and radiographic examination of the left humerus revealed a complete, comminuted, mid-diaphyseal fracture. Blood was collected for a complete blood count and chemistry panel, and a transtracheal wash was performed and submitted for cytologic examination.
Blood work revealed mild inflammation characterized by a reactive thrombocytosis (907 thou/uL; reference interval [RI]: 252-724 thou/uL) and mild hyperfibrinogenemia (700 mg/dL; RI 100-600 mg/dL, by heat precipitation) with an acute phase response represented by a mild hypoalbuminemia (2.4 g/dL; RI: 3.3-4.3 g/dL) and mild decrease in total iron binding capacity (TIBC, 286 ug/dL; 320-490 ug/dL). A mild hypocalcemia (8.7 mg/dL; RI: 8.9-10.9 mg/dL) was attributed to the hypoalbuminemia (decreased protein-bound fraction).
Images of the transtracheal wash are provided. Evaluate the photomicrographs and answer the following questions:
Which is/are the predominant cell(s) population in the tracheal wash?
Based on the images, what are your differential diagnoses?
What further tests should be performed?
Figure 1: Tracheal wash in a bull calf (Wright’s stain, 20x objective)
Figure 2: Tracheal wash in a bull calf (Wright’s stain, 100x objective)
Figure 3: Tracheal wash in a bull calf (Wright’s stain, 100x objective)