Kidney Immunos

Question 1

What is the immunoprofile of Clear Cell RCC?

Answer 1

Positive for: CAIX, CD10, EMA

NEGATIVE for: CK7, AMACR, CD117

Question 2

What RCCs are positive for CK7?

Answer 2

Papillary RCC (in low grade, usually lost in high grade)

Clear Cell Papillary (strong, diffuse)

Chromophobe RCC (diffuse)

Oncocytoma (focal)

Question 3

What is the immunoprofile of papillary RCC?

Answer 3

CK7+ (in low grade)

AMACR+

Question 4

Immunos shared by Chromophobe and Onococytoma?

Answer 4

Both are + for C-Kit /CD117

Both can be positive for CK7 (although chromophobe is diffuse)

Both are Vimentin negative

Chromophobe stains with Hale colloidal iron

Question 5

What kidney tumors are positive for Cathepsin K?

Answer 5

Angiomyolipoma (AML)

Translocation-associated RCC (MiTF) +/-

Question 6

What is the immunoprofile of HLRCC?

Answer 6

Loss of Fumarate Hydratase (FH)
2SC+

PAX 8+

All the other usual markers negative
(i.e. negative for Ck7, CAIX, AMACR, Ckit, Cathepsin K, melanocytic)

Question 7

What is the immunoprofile of Angiomyolipoma?

Answer 7

Positive:
Melanocytic markers (HMB 45, Melan-A)

Cathepsin K

SMA, Calponin

Negative:
PAX 8 !!!!!

Question 8

What is the immunoprofile of Clear Cell Papillary RCC?

Answer 8

Positive:
CK7
CAIX cup-like
PAX8

Negative:
AMACR, C-Kit, Cathepsin K, melanocytic markers

Question 9

What immunos would you use to distinguish between a metanephric adenoma, papillary RCC type 1, and a Wilms tumor?

Answer 9

Papillary RCC: CK7+ diffuse, AMACR +

Wilms: WT1 + CD57 -
CK7 & AMACR -

Metanephric Adenoma: WT1 + CD57+, BRAF+
CK7 & AMACR -

Question 10

What is the immunoprofile of SDH-deficient RCC?

Answer 10

PAX8+, loss of SDH-B;

all the other usual immunos negative.

Question 11

What is the immunoprofile of MITF RCC?

Answer 11

TFE3 or TFEB + (but usually need cytogenetic or molecular assay to confirm)
PAX8 +

CK7 negative

May have some (+/-):
CAIX
AMACR
C-kit/CD117
Cathepsin K
Melanocytic markers (HBM45, Melan-A)

Question 12

List 4 immunos useful in the diagnosis of Wilms tumor

Answer 12

Positive:
PAX8
WT1
Keratin
CD56

diffuse strong p53 in anaplasia may contribute