Kidney tumor - adult malignancies
Adult renal cell carcinoma
Mucinous tubular and spindle cell carcinoma

Author: Sean Williamson, M.D. (see Authors page)

Revised: 1 February 2017, last major update June 2012

Copyright: (c) 2003-2017,, Inc.

PubMed Search: Mucinous tubular spindle cell carcinoma kidney

Cite this page: Mucinous tubular and spindle cell carcinoma. website. Accessed May 29th, 2017.
Definition / general
  • Low grade polymorphic renal epithelial neoplasm with variable components of tubular architecture, extracellular mucinous material and spindle cell areas
  • Also called low grade tubular mucinous renal neoplasm, low grade collecting duct carcinoma, low grade myxoid renal epithelial neoplasm with distal nephron differentiation
  • First described in 2001 - 2002 (Hum Pathol 2001;32:506, Mod Pathol 2002;15:1162), prior cases were classified as sarcomatoid papillary renal cell carcinoma or unclassified
  • Epidemiology: primarily women, 32 - 79 years
  • Origin: tumor cells apparently have differentiation of distal nephron segments
Clinical features
Case reports
Gross description
  • Well circumscribed, 3 - 10 cm, confined to kidney, often with epicenter in renal medulla; yellow / tan / brown / pink cut surface; may have focal hemorrhage; no renal vein invasion
Gross images

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Tan brown cut surface with focal hemorrhage

Microscopic (histologic) description
  • Well circumscribed with partial surrounding rim of compressed fibrous tissue
  • Long tubular profiles or cord-like growth pattern of uniform, low cuboidal cells with eosinophilic, focally vacuolated cytoplasm and spindling, low grade nuclei
  • Stroma is myxoid and bubbly with abundant extracellular mucin; focal clusters of foamy macrophages
  • May have limited mucin (highlighted by Alcian blue), well formed papillae, clear cells, necrosis (Am J Surg Pathol 2006;30:1554)
  • Rarely neuroendocrine differentiation (Am J Clin Pathol 2006;125:99)
  • No desmoplasia, no inflammation, no psammoma bodies, no infiltrative growth, no atypia, no hobnail epithelium, no cysts
Microscopic (histologic) images

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Circumscribed tumor

Long cords and tubules with bland nuclear features in myxoid stroma

Patient with 3 tumors resected at different times

Areas of spindled growth

Various images

Case with sarcomatoid growth

Left: extracellular mucin;
Right: foamy macrophages


Left - Alcian blue+; Right - Hale’s colloidal iron+

Myxoid stroma is Alcian blue+

Peanut agglutinin (PNA)+,
EMA+, CK18+, CK19

Virtual slides

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53 year old woman

Cytology description
Positive stains
Negative stains
  • RCC Ma (positive in 7%), villin, low proliferative rate (< 1%)
Electron microscopy description
  • Tubular structures reminiscent of the loop of Henle or distal convoluted tubule
Molecular / cytogenetics description
  • Multiple chromosomal losses (-1, -4, -6, -8, -9, -13, -14, -15, -22) but no identifiable pattern (Mod Pathol 2006;19:186)
Molecular / cytogenetics images

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H&E and FISH


Differential diagnosis