Buffalo Hump:  An abnormal accumulation of adipose tissue (fat) in the upper back and lower neck, most often seen in patients with excess cortisol production from Cushing’s syndrome or Cushing’s disease (an ACTH-secreting pituitary adenoma).  In patients with Cushing’s disease, other abnormal accumulations of fatty tissue can occur in the area between the neck and shoulders (supraclavicular fat pads) and in the trunk and abdominal area. Learn more.