PA27.17 | Kidney Disease & Tumour Morphology — Practical — Summary & Reflection

REFLECT

Take 3 minutes to write (or think through) answers to these:

1. You are shown a slide with abundant clear cytoplasm cells arranged in sheets around thin-walled vascular sinusoids. You also see areas of haemorrhage. The patient is a 55-year-old with a history of haematuria. Walk through your systematic approach — compartment, pattern, diagnosis.

1. A slide shows tubules that look like thyroid follicles with pale, homogeneous pink casts. There is periglomerular fibrosis but the glomerular tufts themselves look relatively intact. What is the diagnosis, and what would the gross specimen show?

1. Which two renal lesions can only be confirmed (or primarily diagnosed) by EM rather than H&E? What does EM show in each?

(Review your answers after completing the Summary block. There are no 'wrong' responses — the goal is to notice gaps in your reasoning before exam day.)

KEY TAKEAWAYS

Core framework: Gross (size/surface/cysts/mass) → Compartment (glomerular/tubular/interstitial/vascular) → Pattern → Diagnosis.

Glomerular:
• KW nodules + efferent hyalinosis → Diabetic nephropathy
• Cellular crescents in Bowman's space → Crescentic GN
• Spike-and-dome on silver stain → Membranous nephropathy
• Normal LM + foot process effacement (EM) → MCD

Tubulointerstitial:
• Muddy-brown casts + tubular necrosis → ATN
• WBC casts + microabscesses → Acute pyelonephritis
• Thyroidisation + calyceal blunting + periglomerular fibrosis → Chronic pyelonephritis

Vascular:
• Hyaline arteriolosclerosis + finely granular kidney → Benign nephrosclerosis
• Onion-skin + fibrinoid necrosis → Malignant nephrosclerosis

Gross kidneys:
• Finely granular contracted → End-stage (look at micro for cause)
• Massively enlarged bilateral cysts → ADPKD
• Dilated calyces, thin parenchymal rim → Hydronephrosis

Tumours:
• Golden-yellow cortical mass, clear cells, chicken-wire vessels → Clear-cell RCC
• Child, triphasic blastema+stroma+epithelium → Wilms
• Papillary pelvic mass, transitional cells → Urothelial carcinoma

Special stains: PAS for GBM/KW; silver (Jones) for spike-and-dome; Congo red for amyloid.

EM-only diagnoses: MCD (foot process effacement) and membranous nephropathy (subepithelial deposits confirmed on EM in early/equivocal cases).