Kidney - prev exam q Flashcards
1
Q
oncocytoma
histo variants
A
- Classic
- tubulocystic
- mixed
2
Q
A
3
Q
Describe classic histo pattern of oncycytoma
A
- Organoid pattern with well-defined nests of tumor cells
- Edematous, myxoid, or hyalinized stroma
- Confluent nests of tumor cells can be seen at the periphery of the lesion; nests of tumor cells should be outlined by interlacing framework of thin fibrous septa
4
Q
Describe
- Tubulocytsic oncocytoma
- Mixed oncocytoma
A
Tubulocystic
- Variably sized tubular and cystic structures
- Spaces often contain eosinophilic secretion
Mixed pattern
- Composed of both organoid and tubular architecture
5
Q
Cytological features oncocytoma
A
- Tumor cells have finely granular eosinophilic cytoplasm
- Round nuclei with smooth, regular contour and evenly distributed chromatin
- Presence of nucleoli is variable; may be absent or prominent
- Absence of mitotic figures
- Focally cells with hyperchromatic, smudged nuclei may be seen
Other unusual features
- Focal extension into perirenal fat, which has no adverse effect on the prognosis
- Focal cytoplasmic clearing, especially in scarred area
6
Q
Features that are inconsistent with a diagnosis of Oncocytoma
A
- Gross extension into perirenal adipose tissue or gross vascular invasion
- Papillary architecture
- Sarcomatous or spindle cell areas
- Atypical mitotic figures
- Positive for colloidal iron stain
7
Q
IPX oncocytoma
A
- Cytokeratin 7 stains single cells or clusters of cells
- Vimentin: negative
- S100A1: positive
- Hale’s colloidal iron stain: negative or only stains luminal cytoplasm
- E-cadherin and kidney specific cadherin: positive
- Claudin 8: positive cytoplasmic staining
8
Q
ONCOCYTOMA PEARLS (4)
A
- Believed to arise from the intercalated cells of collecting ducts
- Oncocytomas are benign tumors; previous reports of malignant oncocytomas are almost certain RCC misdiagnosed as oncocytomas
- Most common histologic features include well-defined nests of eosinophilic tumor cells separated by fine, delicate fibrous bands and a central fibrous scar
- Hybrid oncocytic tumors with features of both oncocytoma and chromophobe RCC (HOCT) can be seen in patients with Birt-Hogg-Dube syndrome
9
Q
DDX oncocytoma
A
- Eosinophilic variant of clear cell RCC
- Chromophobe RCC, eosinophilic variant
- Renal oncocytosis
10
Q
RCC WITH EOSINOPHILIC CYTOPLASM
A
- Eosinophilic cytoplasm can be seen in high-grade clear cell RCC, but presence of clear cells or papillary structures precludes the diagnosis of oncocytoma
- Nuclear grade is usually high and mitosis readily identifiable
- Cytokeratin 7 negative, but vimentin positive
- E-cadherin: negative
11
Q
CHROMOPHOBE RCC, EOSINOPHILIC VARIANT
A
- Sheetlike compact growth pattern
- “Raisinoid” nuclei and perinuclear halos
- Cytokeratin 7 diffusely positive; Hale’s colloidal iron positive
- E-cadherin: positive
- S100A1: negative
- Claudin 8: positive membranous staining
12
Q
RENAL ONCOCYTOSIS
A
- Renal parenchyma diffusely involved by numerous oncocytic nodules and oncocytic changes: infiltrative growth of oncocytic cells, cortical cysts with oncocytic features, oncocytic changes in non-neoplastic tubules
- Unilateral or bilateral
- May occur in a sporadic form or associated (1/2) with chronic renal failure/long-term hemodialysis
13
Q
Clinical Angiomyolipoma
A
1/5 are assoc with tuberous sclerosis
Sporatic cases are single, unilateral
TS cases are multpile, bilateral
Sharply demarcated leson, unencapsulated
Varigated cuts surface: vascular and adipose tissue and grey white solid areas corresponding to the smooth muscle component
14
Q
histopathology of AML
A
- Triphasic tumor consisting of smooth muscle, mature adipose tissue, and thick-walled hyalinized blood vessels in varying proportion
- One component may predominate
- Atypical features may occasionally be seen, including nuclear pleomorphism and mitosis
- Smooth muscle areas may show epithelioid differentiation with cells having abundant eosinophilic cytoplasm and large nuclei with prominent nucleoli
15
Q
IPX AML
A
- Melanocytic markers: positive
- Smooth muscle markers: positive in smooth muscle component
- Epithelial markers: negative