Non‐functional metastatic thyroid carcinoma with oesophageal invasion and ulceration in a cat

Abstract

An adult, male, neutered, domestic shorthair cat was presented with a 2‐month history of dysphagia and a movable cervical mass. Cytology of the cervical mass was consistent with carcinoma. Thoracic radiographs revealed pleural effusion, cardiomegaly, diffuse patchy interstitial pattern and pulmonary nodules. Fluid analysis of the pleural effusion was consistent with marked septic neutrophilic inflammation, and Pasteurella multocida was isolated. Contrast‐enhanced cervical and thoracic computed tomography scan revealed a cervical mass in the region of the right thyroid lobe, with circumferential invasion of the oesophageal wall and well‐defined pulmonary nodules consistent with distant metastases. Oesophago‐gastroscopy was performed and revealed a proximal, oesophageal, mural mass causing severe intraluminal obstruction. Humane euthanasia was elected. Postmortem examination with histology and immunohistochemistry confirmed a thyroid carcinoma with oesophageal invasion and pulmonary metastases. The oesophageal mucosa was extensively disrupted and ulcerated by the thyroid carcinoma. Additionally, echocardiogram and postmortem examination confirmed cardiomyopathy and congestive heart failure.