Case 148 - Discussion

Uploaded: 2007-11-20, Updated: 2007-11-20

 

Renal Cell Carcinoma, Collecting Duct Type

The Key Features

  • Collecting (Bellini's) duct origin; usually located in the medulla;

  • Tubulopapillary structure with striking stromal desmoplasia;

  • Mucin and CK-HMW positive.

CLINICAL FEATURES

 
  • <1% of malignant epithelial renal neoplasms in adults;

  • Tumor differentiates towards collecting (Bellini's) duct;

  • In the WHO classification, it is grouped with RCC and designed as carcinoma of the collecting ducts of Bellini.

GROSS FINDINGS

 
  • Predominantly localized to the medulla but may invade the cortex with distortion of adjacent calyces and the renal pelvis;

  • Gray or pale-gray, glistening or gelatinous cut surface with invasive borders.

  • Hemorrhage, necrosis cystic changes often present.

MICROSCOPIC FINDINGS

 
  • Composed of a mixture of dilated tubules and papillae. In most cases, the predominant pattern is tubular with variable dimensions and a sponge-like appearance.

  • Both tubules and papillae are lined by a single layer of cuboidal to columnar cells that often have a hobnail pattern. The cytoplasm is amphophilic to acidophilic. There is marked nuclear pleomorphism with vesicular to coarse chromatin and single or multiple nucleoli.

  • Sarcomatoid change or signet-ring cells can be seen.

  • Usually infiltration into the adjacent renal parenchyma with a striking desmoplastic response.

  • The adjacent benign renal collecting ducts may show dysplasia.

SUBTYPES

 
  • Classical tubulopapillary type with striking stromal desmoplasia;

  • Lower grade, often partially cystic tumors;

  • Tumor arising from the loop of Henle: parallel or paired sheets of cuboidal cells.

IMMUNOHISTOCHEMISTRY AND SPECIAL STAINS

 
  • Positive: peanut agglutinin, EMA and vinculin; mucin;

  • Variable: cytokeratins 7, 8, 18; and CK-HMW;

  • Negative: RCC.

TREATMENT AND PROGNOSIS

 
  • Usually aggressive.

REFERENCES

 
  • Rosai and Ackerman's Surgical Pathology, 9th edition

  • AFIP, tumor of the kidney, bladder and related urinary structures, series 4