08/01/2026
AI Cytology Called It “Inflammation.” Histopathology Called It a “Malignant Tumor.” An Oregon Veterinary Hospital Is Now Suing Zoetis
(Important note: The following summary is based on reporting by The Oregonian/OregonLive and The Independent. The reports describe allegations made in the complaint, which represent only one side of the dispute. The case has not yet been tried, and the court has made no findings of fact. According to the reports, Zoetis had not responded to media inquiries at the time of publication.)
[News Summary]
Columbia Veterinary Hospital in The Dalles, Oregon, filed a lawsuit against Zoetis in Wasco County last Thursday, alleging fraud and violations of Oregon’s Unlawful Trade Practices Act. The hospital is seeking at least $50,000 in damages.
According to the complaint, an 11-year-old Belgian Tervuren was evaluated for a rapidly enlarging mass on the neck. In October 2025, the hospital submitted a cytology sample for analysis using Zoetis’s Vetscan Imagyst platform. The complaint alleges that the AI system detected mast cells and spindle cells but ultimately classified the lesion as inflammatory rather than neoplastic.
Based on that interpretation, the veterinarian surgically removed the mass. Subsequent histopathologic evaluation by the Oregon State University Veterinary Diagnostic Laboratory reportedly identified the lesion as an invasive malignant tumor.
The plaintiff alleges that the dog’s death was directly related to the need for a second invasive surgery, performed within a very short period, to achieve complete tumor removal. The complaint further argues that the second surgery would not have been necessary if Imagyst had initially identified the lesion as malignant, as the plaintiff believes Zoetis’s marketing led users to expect.
The lawsuit claims that Zoetis promoted Imagyst as “the world’s most capable veterinary AI analyzer,” leading the hospital to believe that the system would provide diagnostic results comparable to those of an expert.
The complaint also alleges that Zoetis modified the original AI interpretation report after being notified of the alleged misclassification. According to the filing, Zoetis requested a conference call after the hospital reported the case. During that call, company representatives allegedly apologized, acknowledged fault, and stated that other Imagyst users had experienced similar incidents.
[My Perspective]
Cytology is not, and has never been, 100% accurate. Mast cells can also be present in small numbers within inflammatory lesions. Without reviewing the original cytology slides, I cannot determine whether the interpretation was unreasonable or whether the diagnostic limitations were adequately communicated.
That said, if an incorrect cytologic interpretation alone is sufficient grounds for taking legal actions, the concern would extend beyond AI systems. Even board-certified veterinary clinical pathologists could potentially face similar claims. The difference is that few specialists would describe themselves as “the world’s most capable veterinary clinical pathologist.”
Regardless of the eventual legal outcome, this dispute highlights a meaningful gap between how companies market veterinary AI services and how veterinarians understand the capabilities, limitations, and appropriate clinical use of those systems.
This is why teaching AI literacy to veterinary professionals is so important!
Sources:
The Oregonian/OregonLive. “Oregon veterinary hospital sues tech company, claims AI misdiagnosis led to dog’s death.” July 2026.
The Independent. “Oregon vet sues AI company saying misdiagnosis of cancer tumor led to 11-year-old dog’s death.” July 2026.
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