Renal tumors-1 Renal tumors-1 Dr. Abdelaty ShawkyDr. Abdelaty Shawky

Assistant professor of pathologyAssistant professor of pathology

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* Classification of Renal tumors:

I. Benign tumors:I. Benign tumors:

•Cortical adenoma.

•Oncocytoma.

II. Malignant tumors:II. Malignant tumors:

•Renal cell carcinoma.

•Wilms tumor.

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• With the exception of oncocytoma, benign tumors

rarely cause clinical problems.

• Malignant tumors, on the other hand, are of great

importance clinically and deserve considerable

emphasis.

• By far the most common of these malignant tumors is

renal cell carcinoma that affects adults, followed by

Wilms tumor, which is found in children

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Renal cortical adenomaRenal cortical adenoma

* Clinical Features:

•Usually an incidental finding.

•Often seen in patients receiving long-term

hemodialysis, also more common in kidneys

scarred from chronic pyelonephritis.

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* Gross examination:

•The tumor is smaller than 5 mm.

•Soft, well-circumscribed mass with yellow to

gray cut surface surrounded by compressed

adjacent kidney parenchyma

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* Microscopic examination:

•They are composed of papillomatous structures,

tubules, and glands.

•The cells are cuboidal in shape and have small

central nuclei, scanty cytoplasm, and no atypia.

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Renal adenoma

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Renal oncocytoma

* Clinical Features:

•Most cases are asymptomatic, although flank

pain may be a presenting complaint; hematuria

may be seen.

•CT or MRI may identify a central scar.

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* Gross Pathology:•Well-circumscribed, homogeneous cortical tumor

•Mahogany-brown cut surface.

•Often shows a central, irregular fibrous scar.

•Bilateral or multicentric in 2% to 3% of cases

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Renal Renal oncocytomaoncocytoma

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• On microscopic examination: the

tumor consists of large, eosinophilic cells

having small nuclei that have large nucleoli.

The cells are arranged in nests separated by

edematous and hyalinized fibrous stroma.

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Renal oncocytomaRenal oncocytoma

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Renal cell carcinomaRenal cell carcinoma

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* Epidemiology:

•Renal cell carcinomas represent about 1% to 3% of all

visceral cancers and account for 85% of renal malignancy in

adults.

•The tumors occur most often in older individuals, usually

in the sixth and seventh decades of life, showing a male

preponderance in the ratio of 3:1.

•Most renal cancer is sporadic, but unusual forms are a

familial. 14

* Risk factors for RCC:1. Cigarette smoking is the most significant risk

factor.2. Obesity (particularly in women).3. Hypertension. 4. Unopposed estrogen therapy.5. Exposure to asbestos, petroleum products,

and heavy metals.6. Acquired polycystic kidney disease secondary

to dialysis15

* Clinical presentation of RCC:1. Hematuria.

2. Flank pain.

3. Flank lump.

• This triad is seen in only 10% of cases. The most reliable

of the three is hematuria, but it is usually intermittent

and may be microscopic; thus, the tumor may remain

silent until it attains a large size.

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• Renal cell carcinoma tends to produce a diversity

of systemic symptoms not related to the kidney

termed paraneoplastic syndromes, ascribed to

abnormal hormone production including;

– Polycythemia.

–Hypercalcemia.

–Hypertension.

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–Hepatic dysfunction.

– Feminization or masculinization.

–Cushing syndrome.

– Leukemoid reactions.

–Amyloidosis.

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• One of the common characteristics of this tumor is its tendency to metastasize widely before giving rise to any local symptoms or signs.

• In 25% of patients with renal cell carcinoma, there is radiologic evidence of metastases at the time of presentation.

• The most common locations of metastasis are the lungs (more than 50%) and bones (33%), followed in order by the regional lymph nodes, liver and adrenals, and brain.

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* Classification of Renal Cell Carcinoma:

1. Clear cell RCC.1. Clear cell RCC.

2. Papillary RCC.2. Papillary RCC.

3. Chromophobe RCC. 3. Chromophobe RCC.

4. Collecting duct carcinoma.4. Collecting duct carcinoma.

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1. Clear cell RCC.1. Clear cell RCC.• This is the most common type, accounting for

70% to 80% of RCC.* Gross Pathology:• Solitary renal cortical mass• Bilaterality and multifocality more common in

familial cases.• Well-circumscribed, lobulated with golden-yellow

cut surface.• Cystic change, hemorrhage, necrosis, and

calcification often present21

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* Histopathology:•Nests of clear cells interspersed by delicate vascular network.

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References:Robbins and Cotran’s:

Pathologic Basis of Disease. Seventh edition.

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