Kidney tumor

Adult renal cell carcinoma - rare

Mucinous tubular and spindle cell carcinoma

Last author update: 1 June 2017
Last staff update: 17 March 2023 (update in progress)

Copyright: 2003-2023,, Inc.

PubMed Search: Mucinous tubular spindle cell carcinoma kidney

Nicole K. Andeen, M.D.
Maria Tretiakova, M.D., Ph.D.
Page views in 2022: 7,423
Page views in 2023 to date: 1,851
Cite this page: Andeen NK, Tretiakova M. Mucinous tubular and spindle cell carcinoma. website. Accessed March 24th, 2023.
Definition / general
  • Renal epithelial neoplasm characterized by "tubular formations merging with bland spindle cells and a myxoid stroma" (WHO 2016)
  • Low grade polymorphic renal epithelial neoplasm with variable components of tubular architecture, extracellular basophilic mucinous material and spindle cell areas
  • First described in 2001 - 2002 (Hum Pathol 2001;32:506, Mod Pathol 2002;15:1162); prior cases classified as sarcomatoid papillary renal cell carcinoma or unclassified
Essential features
  • Usually bland renal epithelial neoplasm with tubules merging with bland spindle cells in a myxoid stroma; behavior generally indolent
  • May share immunohistochemical (CK7+, AMACR+) and morphologic features with papillary renal cell carcinoma but genetically distinct
  • Previously called low grade tubular mucinous renal neoplasm, low grade collecting duct carcinoma, low grade myxoid renal epithelial neoplasm with distal nephron differentiation
Clinical features
Case reports
  • Resection; additional therapy may be indicated
Gross description
    • Well circumscribed, 2 - 10 cm (mean 4 cm)
    • Confined to kidney; grayish white to tan to yellow glistening cut surface; may have focal hemorrhage; no renal vein invasion
Gross images

Images hosted on other servers:

Cut surface with focal hemorrhage

Microscopic (histologic) description
  • Long tubular profiles or cord-like growth pattern of uniform, bland, low cuboidal cells with eosinophilic, focally vacuolated cytoplasm which transition to anastomosing spindle cells
  • Stroma is myxoid and bubbly with abundant extracellular mucin; focal clusters of foamy macrophages
  • Well circumscribed with partial surrounding rim of compressed fibrous tissue
  • Some cases may be mucin poor (highlighted by Alcian blue)
  • May have well formed papillae, clear cells, foamy macrophages, necrosis (Am J Surg Pathol 2006;30:1554, Ann Diagn Pathol 2007;11:13) or rarely neuroendocrine differentiation (Am J Clin Pathol 2006;125:99)
  • Rare high grade nuclei and sarcomatoid change have been described
  • Generally no desmoplasia, no inflammation, no infiltrative growth, no hobnail epithelium, no cysts
Microscopic (histologic) images

Contributed by Nicole K. Andeen, M.D. and Maria Tretiakova, M.D., Ph.D.

Mucinous tubular and spindle cell carcinoma

Contributed by Dr. Constantina Petraki and the Genitourinary Pathology Society (Case #501)


Images hosted on other servers:

Long cords and
tubules with bland
nuclear features
in myxoid stroma

Case with sarcomatoid growth

Myxoid stroma is Alcian blue+

Cytology description
Positive stains
Negative stains
  • RCC Ma (positive in 7%), villin, Ki67 highlights low proliferative rate (< 1%)
Electron microscopy description
  • Moderate amount of mitochontria, rough endoplasmic reticulum, dense core granules and focal microvilli
  • No renin granules or glycogen (Pathol Int 2004;54:201)
Molecular / cytogenetics description
  • Hypodiploid with multiple chromosomal losses (-1, -4, -6, -8, -9, -13, -14, -15, -22), some hypertriploid but no identifiable pattern (Mod Pathol 2006;19:186)
  • No trisomies 7 / 17 or loss of Chr Y
Molecular / cytogenetics images

Images hosted on other servers:


Differential diagnosis
  • Collecting duct carcinoma: high nuclear grade, desmoplasia and infiltrative features; mucinous tubular and spindle cell carcinoma is usually low grade and well circumscribed
  • Metanephric adenoma: lacks spindled cells and mucinous stroma; positive for WT1 and CD57, negative for AMACR and CK7
  • Papillary renal cell carcinoma (PRCC): both papillary renal cell carcinoma and mucinous tubular and spindle cell carcinoma may have papillae, mucin, low grade features, foam cells, AMACR and CK7 expression
    • look for more prominent mucinous tubular and spindle cell carcinoma biphasic features of anastomosing tubules with spindle cells in mucinous stroma
    • PRCC diffusely express CD10 and has classic trisomy 7 / 17 genomic signature (Am J Surg Pathol 2008;32:1353, Mod Pathol 2006;19:488)
  • Sarcomatoid renal cell carcinoma: infiltrative, usually a high degree of nuclear pleomorphism, areas of more typical renal cell carcinoma subtypes
  • Smooth muscle tumor: more distinct fascicular architecture, absence of tubular areas
Board review style question #1
If necessary, one reliable feature to distinguish mucinous tubular and spindle cell carcinoma from papillary renal cell carcinoma in a challenging case is:

  1. Clinical and radiographic evaluation
  2. Genomic evaluation
  3. Immunohistochemistry
  4. Morphologic features of papillary growth and foam cells
Board review style answer #1
B. The papillary genomic signature of +7, +17 and loss of chromosome Y is not shared with mucinous tubular and spindle cell carcinoma

Comment Here

Reference: Mucinous tubular and spindle cell carcinoma
Back to top
Image 01 Image 02