Renal tumors-1

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Renal tumors-1

• Dr. Abdelaty Shawky
• Assistant professor of pathology

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Classification of Renal tumors

• I. Benign tumors
• Cortical adenoma.
• Oncocytoma.
• 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 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 complex, branching,
  papillomatous structures. The cells may also grow
  as tubules, glands, and cords.
• The cells are cuboidal to polygonal in shape and
  have regular, small central nuclei, scanty
  cytoplasm, and no atypia.

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Renal adenoma
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Renal oncocytoma

• Clinical Features
• Most 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 (in
  about
• 40 of cases).
• Bilateral or multicentric in 2 to 3 of cases

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Renal oncocytoma
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• On microscopic examination the tumor consists of
  large, eosinophilic cells having small, round,
  benign-appearing nuclei that have large nucleoli.
  The cells are arranged in nests separated by
  edematous and hyalinized fibrous stroma.

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Renal oncocytoma
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Renal 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 31.
  

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• Because of their gross yellow color and the
  resemblance of the tumor cells to clear cells of
  the adrenal cortex, they were at one time called
  hypernephroma. It is now clear that all these
  tumors arise from tubular epithelium and are
  therefore renal adenocarcinomas.
• Most renal cancer is sporadic, but unusual forms
  of autosomal-dominant familial cancers occur,
  usually in younger individuals.

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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
   dialysis

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Clinical presentation of RCC

• Hematuria.
• Flank pain.
• 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.
• 2. Papillary RCC.
• 3. Chromophobe RCC.
• 4. Collecting duct carcinoma.

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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 present

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

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References Robbins and Cotrans Pathologic
Basis of Disease. Seventh edition.