What is the primary feature of Kimmelstiel-Wilson nodules?

Kimmelstiel-Wilson nodules are a characteristic pathological feature associated primarily with diabetic nephropathy, which is a common complication of diabetes mellitus. These nodules are formed in the mesangial matrix of the glomeruli and are associated with the changes that occur due to chronic hyperglycemia.

In diabetic nephropathy, there is an increase in the synthesis of extracellular matrix components, leading to the formation of these nodules. They appear as nodular glomerulosclerosis due to the excessive deposition of mesangial matrix and rearrangement of capillary loops. The presence of Kimmelstiel-Wilson nodules is integral to the diagnosis of diabetic kidney disease, which is why they are primarily noted in the context of diabetes.

The association of Kimmelstiel-Wilson nodules with diabetic nephropathy makes option C the correct choice. The other options, while they represent features seen in various renal pathologies, do not specifically relate to Kimmelstiel-Wilson nodules and their identification in the setting of diabetic changes in the kidneys.