Ch. 15 - Kidney & Adrenal Gland Flashcards
What are some accepted indications for FNA of kidney lesions?
Surgical non-candidacy (metastatic disease, comorbidities)
Equivocal radiologic impression
Suspected infection
What are the possible complications of renal FNA?
Bleeding (hematuria, AV fistula), urinoma. Needle tract seeding is very rare.
What ancillary studies are useful in evaluation of renal FNA?
Cytogenetics (FISH), immunohistochemistry.
What criteria are used for adequacy of renal FNA?
There are NO CONSENSUS CRITERIA for renal FNA.
Describe the morphologic appearance of renal glomeruli.
Highly cellular globular structures lacking atypia and with uneven nuclear distribution (ie, denser at the center). Capillary loops should be present.
Describe the morphologic appearance of proximal and distal tubular cells.
Proximal: Round bland nuclei with abundant granular cytoplasm and poorly defined borders.
Distal: Round bland nuclei with less cytoplasm and better-defined cell borders.
Describe the cytology of renal oncocytoma.
Numerous isolated cells with abundant eosinophilic granular cytoplasm and round nuclei with Fuhrman grade 2 nucleoli. Can have some pleomorphism.
What entities should be considered in the differential of renal oncocytoma, and how are they distinguished?
Hepatocytes: Contain lupofuscin and bile pigment.
Eosinophilic-variant papillary: Contains papillae, macrophages.
Chromophobe: Diffuse staining with HCI, CK7.
What is the role of cytology in diagnosing renal cortical adenoma?
It is indistinguishable from low-grade papillary RCCs; by definition it is <0.5cm and should therefore not be aspirated nor called on FNA.
Describe the pathophysiology of renal angiomyolipoma.
Arises from the perivascular epithelioid cell. Half of cases occur in Tuberous Sclerosis (men + women), half are sporadic in middle-aged women.
Describe the HISTOLOGY of renal angiomyolipoma, including staining.
Mature fat, blood vessels, and smooth muscle cells (which may be atypical). Stains for HMB45, MelanA.
Describe the cytology of renal angiomyolipoma.
Often paucicellular with little adipose tissue (fat-rich lesions are diagnosable by radiology). Atypical spindled to epithelioid smoth muscle and rare vessels.
Describe the presentation of metanephric adenoma.
A benign rare kidney tumor of older women which may manifest with polycythemia.
Describe the HISTOLOGY of metanephric adenoma.
Tight, uniform tubules lined by bland cells. May contain psammoma bodies.
Describe the cytology of metanephric adenoma.
Short tubules, tight balls, and loose sheets of bland cells with scant cytoplasm.
What is the role of cytology in diagnosing cystic nephroma?
Cystic nephromas can look solid on radiology but have extremely variable cytology and are not appropriate for FNA diagnosis.
What features are seen in FNA of xanthogranulomatous pyelonephritis?
Histiocytes and multinucleated giant cells which should lack atypia. Consider malakoplakia.
What benign entities may sometimes have atypical cells?
Cystic nephroma Renal abscess, XGP Infarct Atypical cysts Angiomyolipoma
How are renal cysts triaged for FNA eligibility? What patients especially benefit?
“Bosniak” scoring system based on radiologic features. Useful in patients on dialysis, or with PKD (both develop cysts and are also at high risk of malignancy)
What is the annual incidence and mortality due to renal cell carcinomas? What is the epidemiology?
65k per year, with 13k deaths. Men are affected more than women, and most cases are associated with tobacco smoking and obesity.
What are the most common renal cell carcinomas?
- Clear cell
- Papillary
- Chromophobe
- Sarcomatoid
- Rare stuff (collecting duct, translocation, mucinous tubular)
Describe the cytology of clear cell RCC.
Lots of blood. Large cohesive groups of cells with abundant vacuolated cytoplasm and eccentric nuclei. May see fibrillary basement membrane material or vessels.
Describe the cytology of papillary RCC.
True papillae distended with foamy macrophages. Cells resemble distal tubular cells and may also have intracytoplasmic hemosiderin.
What is the immunostaining profile of papillary RCC?
Stains EMA, LMWKs (CK7), and is negative for 34BE12 and WT-1.
Describe the cytology of chromophobe RCC.
Less cohesive cells with fluffy cytoplasm and marked nuclear variation (binucleation, grooves, pseudoinclusions). Koilocytoid.
Describe the cytology of sarcomatoid RCC. Staining?
High-grade spindled to epithelioid lesion with keratin or EMA reactivity.
What are some distinct features of collecting duct carcinoma?
Medullary location, poor definition, prominent desmoplasia. Stains 34BE12.
What are some distinct features of Xp11.2 translocation associated RCC?
Pediatric population, TFE3 gene rearrangement, frequent calcifications.
What are some distinct features of mucinous tubular and spindle cell carcinoma?
Rare incidence, excelelnt prognosis. Biphasic cell population (tubular and spindle cells in mucoid matrix).
What percentage of renal tumors are urothelial? What are its associations?
5-10%. Associated with tobacco use, phenacetin, thorium contrast material.
Describe the cytology of urothelial carcinoma.
Large cells with dark hyperchromatic nuclei and smooth cytoplasm. Sometimes elongated or cercariform with a long tail and intracytoplasmic vacuole.
What stains can distinguish RCC from UCC?
34BE12, CK20, GATA3, CEA (UCC)
CD10, RCCma, PAX2, PAX8 (RCC)
What is the most common cancer metastasis to kidney?
Lung
Describe the cytology of Wilms tumor.
Triphasic tumor (at least two components must be present). Blastema (SRBCs), tubules, and stroma.
What entities shouold be kept in the differential for Wilms tumor?
Metanephric adenoma, mesoblastic nephroma, clear cell sarcoma, rhabdoid tumors
What is the role of FNA in the evaluation of adrenal masses?
Mostly to identify metastatic disease (do not FNA without a history of primary disease elsewhere).
Describe the cytology and differential diagnosis of myelolipoma.
Fat and hematopoietic elements. Consider angiomyolipoma (throw melanocytic markers).
Describe the cytology of adrenal cortical adenomas.
Numerous naked nuclei, frothy granular background, and some intact bubbly cells. Note: Indistinguishable from hyperplastic nodule.
Describe the cytology of adrenal cortical carcinomas.
Isolated cells with nuclear atypia, mitoses, and necrosis…nonspecific. Need staining?
What are the rules of 10 in pheochromocytoma?
10% are malignant, 10% are familial, 10% are extra-adrenal, 10% are bilateral.
Describe the cytology of pheochromocytoma.
Highly cellular with clusters and isolated cells with neuroendocrine features. Pseudoinclusions, prominent nucleoli, granular cytoplasm.
What are the most common metastases in adrenal?
Lung cancer, melanoma, RCC.
What are some adrenal cortical stains?
SF1 (NR5A1), inhibin, Melan-A, calretinin
