Kidney Flashcards
Kidney with diffuse mesangial expansion with increased matrix, thickening of the glomerular basement membrane (GBM), and most distinctively, nodular mesangial sclerosis (‘Kimmelstiel-Wilson nodules’) Hyaline arteriolosclerosis, affecting both afferent and efferent arterioles is also highly characteristic.
Diabetic nephropathy
Differential diagnosis:
Renal amyloidosis
Plan:
Correlate with clinical history and radiology
Correlate with findings on EM and IF
Special stains: Congo red, silver stain, PAS
Kidney tumour or metastasis with clear to granular eosinophilic cytoplasm, delicate distinct cell membranes, in sheets and packets divided by network of thin walled vessels. Areas of necrosis, hemorrhage, cystic degeneration, and fibrosis are all common.
Clear cell renal cell carcinoma
Differential diagnosis:
MCRNLMP (if entirely low grade and cystic)
Clear cell papillary renal cell tumour
Chromophobe RCC
Genetically defined RCC subtypes (e.g. MiT family translocation RCCs)
Plan:
Correlate with clinical history and radiology (?familial syndrome)
Examine further blocks (e.g. for total size, relation to margins, vein invasion, areas of high grade features)
IPX to support Dx: CD10, PAX8, CAIX (expect positive, with cup-like CAIX staining)
IPX to discount DDx: CK7, CD117, AMACR
Next steps: Synoptic report, discuss at MDT
Advice to clinician: Usually sporadic, but may be assiociated with VHL syndrome. Clinical correlation is required.
Renal tumour with pushing, circumscribed but unencapsulated border, with tortuous thick walled hyalinised blood vessels, smooth muscle which appears to originate from vessel walls, and mature fat cells without atypia
Angiomyolipoma
Plan:
Correlate with clinical history and radiology
IPX to support Dx: SMA, HMB45, MelanA
Advice to clinician: Can be sporadic or assiociated with tuberous sclerosis. Clinical correlation is required
Nongranulomatous, necrotizing inflammation of medium sized and small arteries of kidney with neutrophils and lymphocytes, without assiociated glomerulonephritis. May be areas of kidney infarction.
Polyarteritis nodosa (PAN)
Differential diagnosis:
Other forms of vasculitis (e.g. ANCA vasculitis, SLE)
Plan:
Correlate with clinical history and radiology (?autoimmune serology ?systemic involvement ?inflammatory markers ?HepB or C ?Familial syndrome)
Examine further blocks
Special stains: Elastic stain (assess elastic lamina of arteries)
Advice to clinician (urgent via phone): This is a potentially life threatening vasculitis. Patient should be investigated and treated in hospital.
Well circumscribed renal tumour with tubules and papillae lined by small cuboidal cells with scant lightly basophilic cytoplasm (imparting overall ‘blue’ appearance at low power), containing foamy histiocytes. Other classic features are hemosiderin deposition and psammoma bodies.
Papillary renal cell carcinoma (low grade, formerly type 1)
Differential diagnosis:
Clear cell papillary renal cell tumour
Metanephric adenoma
Plan:
Correlate with clinical history and radiology
Examine further blocks (e.g. for size, relation to margins, areas of high grade features)
IPX to support Dx: CK7, AMACR (Racemase)
IPX to discount DDx: CAIX, WT1, CD57
Next steps: Synoptic report, discuss at MDT
Renal tumour with tubules and papillae lined by large eosinophilic cells with prominent nucleoli. May have containing foamy histiocytes within papillary cores, hemosiderin deposition and psammoma bodies.
Papillary renal cell carcinoma (high grade, formerly type 2)
Differential diagnosis:
FH deficient RCC
MiT family translocation RCC
Plan:
Correlate with clinical history and radiology
Examine further blocks (e.g. for size, relation to margins, areas of differing morphology)
IPX to support Dx: CK7, AMACR (Racemase)
IPX to discount DDx: FH and 2SC, TFE3 and Cathepsin K
Next steps: Synoptic report, discuss at MDT
Solid growth with nests and sheets of cells of variable shapes and sizes, with sharply defined cell borders that impart an appearance like plant cells. Nuclei are raisinoid (like koilocytes), and binucleation is common. Cytoplasm ranges from clear to granular pink to deep oncocytic pink, classically with perinuclear clearing.
Chromophome renal cell carcinoma
Differential diagnosis:
Clear cell RCC
Oncocytoma
Plan:
Correlate with clinical history and radiology (?Birt-Hogg-Dube syndrome)
Examine further blocks (e.g. for total size, relation to margins)
Special stains to support Dx: Hale’s colloidal iron
IPX to support Dx: CK7, CD117 CKIT
IPX to discount DDx: Vimentin, CAIX, S100A1
Next steps: Synoptic report, discuss at MDT
Advice to clinician: May be sporadic or assiociated with Birt-Hogg-Dube syndrome. Clinical correlation is required.
Small solid nests set within a loose hyalinized or myxoid stroma. Cells are round to polygonal with densely eosinophilic granular cytoplasm and round uniform nuclei with small nucleolus. Mitoses are rare.
Oncocytoma
Differential diagnosis:
Oncocytic chromophobe RCC
Oncocytic clear cell RCC
SDH deficient RCC
Papillary RCC (type 2)
Plan:
Correlate with clinical history and radiology (?Birt-Hogg-Dube syndrome)
Examine further blocks (e.g. for total size, relation to margins, areas of differing morphology)
Special stains to discount DDx: Hale’s colloidal iron (expect negative)
IPX to support Dx: CK7, S100A1
IPX to discount DDx: CD117 KIT, vimentin and CAIX, SDHB, AMACR
Next steps: Synoptic report
Advice to clinician: Benign. May be sporadic or assiociated with Birt-Hogg-Dube syndrome. Clinical correlation is required.
Densely cellular ‘blue’ renal tumour, composed of embryonal cells with small round nuclei and scant cytoplasm, forming tightly packed tubules and serpiginous gland-like structures. Mitoses are rare. Stroma is typically hyalinized and paucicellular, and psammoma bodies are common.
Metanephric adenoma
Differential diagnosis
Papillary renal cell carcinoma (low grade)
Epithelial predominant Wilm’s tumour (if paediatric)
Plan:
Correlate with clinical history and radiology
Examine further sections (e.g. for size, relation to margins, areas of differing morphology)
IPX to support Dx: WT1, CD57, BRAFV600E
IPX to discount DDx: CK7, AMACR
No specific further action required for this benign diagnosis
