A 12-year-old Quarter Horse gelding presents with multiple nodular masses on the medial thighs. The horse previously had multiple nodular proliferations removed from the muzzle. No previous diagnostics were performed.
Clinical description: Multiple flat, raised masses on the medial aspect of both thighs caudal to the sheath.
FIGURES
Figure 2. H&E, 20x magnification
Figure 3. H&E, 100x magnification
Figure 4. H&E, 400x magnification
Figure 5. Immunohistochemistry for CD3
Figure 6. Immunohistochemistry for CD20
November 2025 - What is the most likely diagnosis?
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