Aspirate from a pectoral mass in a horse
A 16-year-old Quarter Horse gelding with a history of low thyroid hormone concentrations was being rechecked for possible pituitary pars intermedia dysfunction (PPID). During blood sampling for measurement of adrenocorticotropic hormone (ACTH), insulin, leptin and thyroxine, a large subcutaneous mass was noted in the pectoral region. A fine needle aspirate of the mass was performed and smears of the aspirate were submitted to the Clinical Pathology laboratory in the Animal Health Diagnostic Center at Cornell University for cytologic evaluation. Examine the representative images of the modified Wright’s-stained smears of the aspirate and then answer the questions below.
- What cell types can you identify in the aspirate?
- What are your differential diagnoses for the mass?
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