Bilateral Thyroid Follicular Atrophy in a Young Canadian Lynx (Lynx canadensis)

Bilateral Thyroid Follicular Atrophy in a Young Canadian Lynx (Lynx canadensis)

A 1.5 year old intact male Canadian Lynx (Lynx canadensis) presented to the referring veterinarian with a 1 year history of poor appetite, lethargy, and weakness with eventual development of neurologic signs (vestibular signs, ataxia). At necropsy, gross lesions were few and non-specific. The lynx had decreased amounts of subcutaneous adipose stores and decreased skeletal muscle mass. Histologically, the thyroid glands were bilaterally decreased in size and approximately 75% of the thyroid gland was replaced by mature adipocytes. The remaining thyroid follicular cells are cuboidal and form follicles of varying sizes (10 µm-100 µm) with a mild amount of colloid.