Graves disease is the most common cause of endogenous hyperthyroidism. It consists of a cluster of clinical findings - diffuse functional hyperplasia of the thyroid, infiltrative ophthalmopathy (exophthalmos), and a localized dermopathy. The peak incidence is between 20 and 40 yrs. of age and female:male ratio is 10:1. This autopsy photograph shows symmetric enlargement of the thyroid gland due to diffuse hypertrophy and hyperplasia. Image Courtesy of : Ed Uthman, MD, Houston, Texas.