Table 5 Key pathologic and immunohistochemical features contrasting oncocytoma, chromophobe renal cell carcinoma, and succinate dehydrogenase-deficient renal cell carcinoma

Cytoplasmic vacuoles

Rare—often empty-appearing

Absent—diffuse or perinuclear flocculent or cleared cytoplasm

Present—large flocculent, eosinophilic or cleared inclusions, some displacing nucleus

Nested growth dispersed in myxohyaline stroma

Often present

Sometimes present

Inconspicuous stroma

Prominent cell borders and perinuclear clearing

Absent

Present

Absent

Large nuclei with degenerative atypia or smudged chromatin

Sometimes present

Sometimes present

Absent

Intratumoral mast cells

Typically inconspicuous

Typically inconspicuous

Sometimes prominent

Entrapped non-neoplastic tubules

Often present

Rarely present

Often present

Colloidal iron

Negative

Positive

Negative

KIT (CD117)

Often positive

Often positive

Negative, but highlights intratumoral mast cells

CK7

Typically scattered single cells

Often positive

Typically negative

S100A1

Typically positive

Typically negative

Highly variable

Vimentin

Negative

Negative

Rarely positive, but highlights intratumoral mast cells

HNF1B

Retained

Lost

Retained

SDHB

Retained

Retained

Lost

SDHA

Retained

Retained

Rarely lost