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Question 1

Answer 1

This is nodular glomerulosclerosis (the Kimmelstiel-Wilson lesion) of diabetes mellitus. Nodules of pink hyaline material form in regions of glomerular capillary loops in the glomerulus. This is due to a marked increase in mesangial matrix from damage as a result of non-enzymatic glycosylation of proteins.

Question 2

Answer 2

This is a PAS stain of nodular glomerulosclerosis (Kimmelstiel-Wilson lesions) in a patient with long-standing diabetes mellitus. Note also the markedly thickened arteriole at the lower right which is typical for the hyaline arteriolosclerosis that is seen in diabetic kidneys as well.

Question 3

Answer 3

This PAS stain demonstrates diffuse
standing diabetes mellitus. There is an increase in mesangial matrix, a slight increase in mesangial cellularity and capillary basement membrane thickening. These changes gradually advance until the entire glomerulus is sclerotic.

Question 4

Answer 4

Hyaline arteriolosclerosis affecting the afferent
and efferent arterioles in a patient with diabetes mellitus

Question 5

Answer 5

This is an ascending bacterial infection leading to acute pyelonephritis. Numerous PMN’s are seen filling renal tubules across the center and right of this picture.

Question 6

Answer 6

The urinary tract can be involved by an ascending urinary tract infection. Diabetics are more prone to develop infections in general. Here are seen budding cells with pseudohyphae with Candida albicans on PAS stain in the renal pelvis.

Question 7

Answer 7

The pale white areas involving some or all of many renal papillae are areas of papillary necrosis. This is an uncommon but severe complication of acute pyelonephritis, particularly in persons with diabetes mellitus. Papillary necrosis may also accompany analgesic nephropathy.

Question 8

Answer 8

Arteriole with circumferential intimal hyalin deposition.

Question 9

Answer 9

Small artery with intimal hyalin and arteriole
to left with intimal deposition of hyalin extending toward the media and compressing smooth muscle cells.

Question 10

Answer 10

Interlobular artery with reduplication of the internal elastic lamina.

Question 11

Answer 11

Glomerulus with wrinkling of the GBM accompanied by reduction of capillary lumen diameter.

Question 12

Answer 12

Kidney from a patient who had the malignant phase of essential hypertension.
Note numerous petechial hemorrhages

Question 13

Answer 13

Small artery with mucinous basophilic intimal thickening.

Question 14

Answer 14

Arteriole showing TMA with platelet-fibrin thrombus occluding the lumen. Also note fragmented red blood cells within the vessel wall

Question 15

Answer 15

Fibrin-platelet thrombi in glomerular capillaries

Question 16

Answer 16

Interstitial nephritis in a 66-year-old patient who did not have any identifiable underlying etiology but had peripheral eosinophilia. A: Interstitial mononuclear cell infiltrate with edema. (PAS, ×100.)
B: Focally large numbers of eosinophils were present in the interstitium. (H&E, ×400.)
C: In several foci, the inflammatory cells infiltrated the tubular epithelium (tubulitis). (PAS, ×600.)

Question 17

Answer 17

White cell casts in acute pyelonephritis.

Question 18

Answer 18

Interlobular artery in a renal biopsy specimen from a patient with MPA showing necrotizing arteritis.

Question 19

Answer 19

Focus of granulomatous interstitial inflammation in a renal biopsy specimen
with no apparent relationship to a glomerulus or vessel. There is a central zone of necrosis
surrounded by an admixture of neutrophils and mononuclear leukocytes and a few multinucleated giant cells (arrow).