Collecting Duct Carcinoma
Definition
- High grade renal adenocarcinoma arising in medulla of the kidney, with a predominantly invasive tubular growth pattern
- Clearly overlaps morphologically and immunophenotypically with medullary carcinoma but the latter has a distinctive clinicopathologic setting
Alternate/Historical Names
- Bellini duct carcinoma
- Carcinoma of the collecting ducts of Bellini
Diagnostic Criteria
- Metastatic adenocarcinoma must be ruled out in every case
- Collecting duct carcinoma should be considered a diagnosis of exclusion
- Firm mass centered on the renal medulla
- Frequently extends into renal cortex and/or pelvis
- Predominantly tubular pattern
- Can have areas of papillary growth
- Occasionally solid or microcystic
- Usually single layer of cuboidal lining cells with hobnail nuclei
- Cytoiplasm usually pale eosinophilic to clear
- Cytoplasmic mucin may be present
- Signet ring cells seen in rare cases
- Rare sarcomatoid cases
- Defined by presence of a distinct spindle cell component occupying at least one microscopic low-power field (×40)
- Can have areas of papillary growth
- Prominent stromal desmoplasia
- Frequent mixed acute and chronic inflammation
- High grade nuclear atypia
- Equivalent to WHO/ISUP 3 or 4
- Nuclei lare, vesicular and highly pleomorphic with prominent nucleoli
- Frequent mitotic figures
- Dysplastic epithelial lining frequently seen in adjacent collecting duct
- Equivalent to WHO/ISUP 3 or 4
- Infiltrative growth pattern
- Edge of tumor poorly defined with infiltration of adjacent kidney
- Extra-renal and vascular invasion frequent
- Absence of any other renal cell carcinoma pattern or of urothelial carcinoma
- Cases described as low grade collecting duct carcinomas in the past are better classified as one of the following
- Renal medullary carcinoma is considered a separate entity
- Considered by some reports to be a variant of collecting duct carcinoma
- Overlaps histopathologically with collecting duct carcinoma but is separated based on the following features
- Occurrence in young patients
- Association with sickle cell trait
- Lack of INI1 expression (Cheng 2008) vs retention in 85% of collecting duct carcinoma (Elwood 2011)
Kurt Schaberg MD
John P Higgins MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/last update: 1/24/11, 11/2/16
